2017-12-20 16:27:51

by Luiz Augusto von Dentz

Subject: [PATCH BlueZ] shared/att: Fix possible crash when security is changed

From: Luiz Augusto von Dentz <[email protected]>

When resending a PDU due to secure change the timeout_id shall also be
removed otherwise the following crash may occur:

Invalid read of size 8
at 0x489639: timeout_cb (att.c:405)
by 0x49417C: timeout_callback (timeout-glib.c:34)
by 0x4E84AB2: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
by 0x4E84049: g_main_context_dispatch (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
by 0x4E843EF: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
by 0x4E84711: g_main_loop_run (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
by 0x40B51F: main (main.c:770)
Address 0x6ce5830 is 32 bytes inside a block of size 192 free'd
at 0x4C2EDEB: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
by 0x48A89D: disconnect_cb (att.c:593)
by 0x493D54: watch_callback (io-glib.c:170)
by 0x4E84049: g_main_context_dispatch (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
by 0x4E843EF: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
by 0x4E84711: g_main_loop_run (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
by 0x40B51F: main (main.c:770)
---
src/shared/att.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/src/shared/att.c b/src/shared/att.c
index 8d58156c1..0aab246d6 100644
--- a/src/shared/att.c
+++ b/src/shared/att.c
@@ -642,6 +642,12 @@ static bool handle_error_rsp(struct bt_att *att, uint8_t *pdu,
if (!change_security(att, rsp->ecode))
return false;

+ /* Remove timeout_id if outstanding */
+ if (op->timeout_id) {
+ timeout_remove(op->timeout_id);
+ op->timeout_id = 0;
+ }
+
util_debug(att->debug_callback, att->debug_data,
"Retrying operation %p", op);

--
2.13.6

2017-12-20 19:58:50

by Szymon Janc

Subject: Re: [PATCH BlueZ] shared/att: Fix possible crash when security is changed

Hi Luiz,

On Wednesday, 20 December 2017 17:27:51 CET Luiz Augusto von Dentz wrote:
> From: Luiz Augusto von Dentz <[email protected]>
>
> When resending a PDU due to secure change the timeout_id shall also be
> removed otherwise the following crash may occur:
>
> Invalid read of size 8
> at 0x489639: timeout_cb (att.c:405)
> by 0x49417C: timeout_callback (timeout-glib.c:34)
> by 0x4E84AB2: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2)
> by 0x4E84049: g_main_context_dispatch (in
> /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2) by 0x4E843EF: ??? (in
> /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2) by 0x4E84711:
> g_main_loop_run (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2) by
> 0x40B51F: main (main.c:770)
> Address 0x6ce5830 is 32 bytes inside a block of size 192 free'd
> at 0x4C2EDEB: free (in
> /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) by 0x48A89D:
> disconnect_cb (att.c:593)
> by 0x493D54: watch_callback (io-glib.c:170)
> by 0x4E84049: g_main_context_dispatch (in
> /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2) by 0x4E843EF: ??? (in
> /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2) by 0x4E84711:
> g_main_loop_run (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4800.2) by
> 0x40B51F: main (main.c:770)
> ---
> src/shared/att.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/src/shared/att.c b/src/shared/att.c
> index 8d58156c1..0aab246d6 100644
> --- a/src/shared/att.c
> +++ b/src/shared/att.c
> @@ -642,6 +642,12 @@ static bool handle_error_rsp(struct bt_att *att,
> uint8_t *pdu, if (!change_security(att, rsp->ecode))
> return false;
>
> + /* Remove timeout_id if outstanding */
> + if (op->timeout_id) {
> + timeout_remove(op->timeout_id);
> + op->timeout_id = 0;
> + }
> +
> util_debug(att->debug_callback, att->debug_data,
> "Retrying operation %p", op);

Applied, thanks.

--
pozdrawiam
Szymon Janc