From: Richard Palethorpe <rpalethorpe@suse.com>
To: linux-can@vger.kernel.org
Cc: Richard Palethorpe <rpalethorpe@suse.com>,
Kees Cook <keescook@chromium.org>,
netdev@vger.kernel.org, security@kernel.org, wg@grandegger.com,
mkl@pengutronix.de, davem@davemloft.net
Subject: [PATCH v2] slcan: Don't transmit uninitialized stack data in padding
Date: Wed, 1 Apr 2020 12:06:39 +0200 [thread overview]
Message-ID: <20200401100639.20199-1-rpalethorpe@suse.com> (raw)
struct can_frame contains some padding which is not explicitly zeroed in
slc_bump. This uninitialized data will then be transmitted if the stack
initialization hardening feature is not enabled (CONFIG_INIT_STACK_ALL).
This commit just zeroes the whole struct including the padding.
Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
Fixes: a1044e36e457 ("can: add slcan driver for serial/USB-serial CAN adapters")
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: linux-can@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: security@kernel.org
Cc: wg@grandegger.com
Cc: mkl@pengutronix.de
Cc: davem@davemloft.net
---
V2: Reviewed by Kees and Fixes tag added.
As mentioned in V1; The following unfinished test can reproduce the bug:
https://github.com/richiejp/ltp/blob/pty-slcan/testcases/kernel/pty/pty04.c
drivers/net/can/slcan.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
index a3664281a33f..4dfa459ef5c7 100644
--- a/drivers/net/can/slcan.c
+++ b/drivers/net/can/slcan.c
@@ -148,7 +148,7 @@ static void slc_bump(struct slcan *sl)
u32 tmpid;
char *cmd = sl->rbuff;
- cf.can_id = 0;
+ memset(&cf, 0, sizeof(cf));
switch (*cmd) {
case 'r':
@@ -187,8 +187,6 @@ static void slc_bump(struct slcan *sl)
else
return;
- *(u64 *) (&cf.data) = 0; /* clear payload */
-
/* RTR frames may have a dlc > 0 but they never have any data bytes */
if (!(cf.can_id & CAN_RTR_FLAG)) {
for (i = 0; i < cf.can_dlc; i++) {
--
2.24.0
next reply other threads:[~2020-04-01 10:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-01 10:06 Richard Palethorpe [this message]
2020-04-01 10:08 ` [PATCH v2] slcan: Don't transmit uninitialized stack data in padding Marc Kleine-Budde
2020-04-01 18:23 ` David Miller
2020-04-01 19:41 ` Oliver Hartkopp
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