On 01/04/2020 12.06, Richard Palethorpe wrote:
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@xxxxxxxx>
Fixes: a1044e36e457 ("can: add slcan driver for serial/USB-serial CAN adapters")
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: linux-can@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Cc: security@xxxxxxxxxx
Cc: wg@xxxxxxxxxxxxxx
Cc: mkl@xxxxxxxxxxxxxx
Cc: davem@xxxxxxxxxxxxx
Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
---
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++) {
