2016-07-29 12:34:07

by Michał Narajowski

[permalink] [raw]
Subject: [PATCH BlueZ v2] monitor/l2cap: Fix buffer overflow when printing UUIDs

> ACL Data RX: Handle 76 flags 0x02 dlen 18 [hci0] 22.985107
ATT: Read By Group Type Response (0x11) len 13
Attribute data length: 6
Attribute group list: 2 entries
Handle range: 0x0001-0x0007
UUID: Generic Access Profile (0x1800)
Handle range: 0x0008-0x000b
UUID: Generic Attribute Profile (0x1801)
< ACL Data TX: Handle 76 flags 0x00 dlen 11 [hci0] 22.985304
ATT: Read By Group Type Request (0x10) len 6
Handle range: 0x000c-0xffff
Attribute group type: Primary Service (0x2800)
> HCI Event: Number of Completed Packets (0x13) plen 5 [hci0] 23.051113
Num handles: 1
Handle: 76
Count: 1
> ACL Data RX: Handle 76 flags 0x02 dlen 26 [hci0] 23.115103
ATT: Read By Group Type Response (0x11) len 21
Attribute data length: 20
Attribute group list: 1 entry
Handle range: 0x000c-0x0010
*** buffer overflow detected ***: monitor/btmon terminated

==14384== Process terminating with default action of signal 6 (SIGABRT)
==14384== at 0x4E6F418: raise (raise.c:54)
==14384== by 0x4E71019: abort (abort.c:89)
==14384== by 0x4EB1729: __libc_message (libc_fatal.c:175)
==14384== by 0x4F5289B: __fortify_fail (fortify_fail.c:37)
==14384== by 0x4F5089F: __chk_fail (chk_fail.c:28)
==14384== by 0x4F4FE08: _IO_str_chk_overflow (vsprintf_chk.c:31)
==14384== by 0x4EB55DF: _IO_default_xsputn (genops.c:455)
==14384== by 0x4E87DBF: vfprintf (vfprintf.c:1631)
==14384== by 0x4F4FE93: __vsprintf_chk (vsprintf_chk.c:82)
==14384== by 0x4F4FDEC: __sprintf_chk (sprintf_chk.c:31)
==14384== by 0x422826: sprintf (stdio2.h:33)
==14384== by 0x422826: print_uuid (l2cap.c:2014)
==14384== by 0x423373: print_group_list (l2cap.c:2334)
==14384== by 0x423373: att_read_group_type_rsp (l2cap.c:2348)
---
monitor/l2cap.c | 2 +-
monitor/uuid.h | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/monitor/l2cap.c b/monitor/l2cap.c
index 59a3206..f4b54af 100644
--- a/monitor/l2cap.c
+++ b/monitor/l2cap.c
@@ -1999,7 +1999,7 @@ static void print_hex_field(const char *label, const uint8_t *data,
static void print_uuid(const char *label, const void *data, uint16_t size)
{
const char *str;
- char uuidstr[36];
+ char uuidstr[MAX_LEN_UUID_STR];

switch (size) {
case 2:
diff --git a/monitor/uuid.h b/monitor/uuid.h
index 6ffc0ee..22d2363 100644
--- a/monitor/uuid.h
+++ b/monitor/uuid.h
@@ -24,6 +24,8 @@

#include <stdint.h>

+#define MAX_LEN_UUID_STR 37
+
const char *uuid16_to_str(uint16_t uuid);
const char *uuid32_to_str(uint32_t uuid);
const char *uuidstr_to_str(const char *uuid);
--
2.7.4



2016-08-12 19:51:57

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: Re: [PATCH BlueZ v2] monitor/l2cap: Fix buffer overflow when printing UUIDs

Hi Michał,

On Fri, Jul 29, 2016 at 3:34 PM, Michał Narajowski
<[email protected]> wrote:
>> ACL Data RX: Handle 76 flags 0x02 dlen 18 [hci0] 22.985107
> ATT: Read By Group Type Response (0x11) len 13
> Attribute data length: 6
> Attribute group list: 2 entries
> Handle range: 0x0001-0x0007
> UUID: Generic Access Profile (0x1800)
> Handle range: 0x0008-0x000b
> UUID: Generic Attribute Profile (0x1801)
> < ACL Data TX: Handle 76 flags 0x00 dlen 11 [hci0] 22.985304
> ATT: Read By Group Type Request (0x10) len 6
> Handle range: 0x000c-0xffff
> Attribute group type: Primary Service (0x2800)
>> HCI Event: Number of Completed Packets (0x13) plen 5 [hci0] 23.051113
> Num handles: 1
> Handle: 76
> Count: 1
>> ACL Data RX: Handle 76 flags 0x02 dlen 26 [hci0] 23.115103
> ATT: Read By Group Type Response (0x11) len 21
> Attribute data length: 20
> Attribute group list: 1 entry
> Handle range: 0x000c-0x0010
> *** buffer overflow detected ***: monitor/btmon terminated
>
> ==14384== Process terminating with default action of signal 6 (SIGABRT)
> ==14384== at 0x4E6F418: raise (raise.c:54)
> ==14384== by 0x4E71019: abort (abort.c:89)
> ==14384== by 0x4EB1729: __libc_message (libc_fatal.c:175)
> ==14384== by 0x4F5289B: __fortify_fail (fortify_fail.c:37)
> ==14384== by 0x4F5089F: __chk_fail (chk_fail.c:28)
> ==14384== by 0x4F4FE08: _IO_str_chk_overflow (vsprintf_chk.c:31)
> ==14384== by 0x4EB55DF: _IO_default_xsputn (genops.c:455)
> ==14384== by 0x4E87DBF: vfprintf (vfprintf.c:1631)
> ==14384== by 0x4F4FE93: __vsprintf_chk (vsprintf_chk.c:82)
> ==14384== by 0x4F4FDEC: __sprintf_chk (sprintf_chk.c:31)
> ==14384== by 0x422826: sprintf (stdio2.h:33)
> ==14384== by 0x422826: print_uuid (l2cap.c:2014)
> ==14384== by 0x423373: print_group_list (l2cap.c:2334)
> ==14384== by 0x423373: att_read_group_type_rsp (l2cap.c:2348)
> ---
> monitor/l2cap.c | 2 +-
> monitor/uuid.h | 2 ++
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/monitor/l2cap.c b/monitor/l2cap.c
> index 59a3206..f4b54af 100644
> --- a/monitor/l2cap.c
> +++ b/monitor/l2cap.c
> @@ -1999,7 +1999,7 @@ static void print_hex_field(const char *label, const uint8_t *data,
> static void print_uuid(const char *label, const void *data, uint16_t size)
> {
> const char *str;
> - char uuidstr[36];
> + char uuidstr[MAX_LEN_UUID_STR];
>
> switch (size) {
> case 2:
> diff --git a/monitor/uuid.h b/monitor/uuid.h
> index 6ffc0ee..22d2363 100644
> --- a/monitor/uuid.h
> +++ b/monitor/uuid.h
> @@ -24,6 +24,8 @@
>
> #include <stdint.h>
>
> +#define MAX_LEN_UUID_STR 37
> +
> const char *uuid16_to_str(uint16_t uuid);
> const char *uuid32_to_str(uint32_t uuid);
> const char *uuidstr_to_str(const char *uuid);
> --
> 2.7.4

Applied, thanks.

--
Luiz Augusto von Dentz