In isotp_rcv_ff() 32 bit of data received over the network is assigned
to struct tpcon::len. Later in that function the length is checked for
the maximal supported length against MAX_MSG_LENGTH.
As struct tpcon::len is an "int" this check does not work, if the
provided length overflows the "int".
Later on struct tpcon::idx is compared against struct tpcon::len.
To fix this problem this patch converts both struct tpcon::{idx,len}
to unsigned int.
Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Link: https://lore.kernel.org/all/20220105132429.1170627-1-mkl@xxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Reported-by: syzbot+4c63f36709a642f801c5@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
net/can/isotp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/can/isotp.c b/net/can/isotp.c
index df6968b28bf4..02cbcb2ecf0d 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -119,8 +119,8 @@ enum {
};
struct tpcon {
- int idx;
- int len;
+ unsigned int idx;
+ unsigned int len;
u32 state;
u8 bs;
u8 sn;
--
2.34.1
