syzbot is able to produce a nasty WARN_ON() in tcp_verify_left_out()
with following C-repro :
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_TCP, TCP_REPAIR, [1], 4) = 0
setsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [-1], 4) = 0
bind(3, {sa_family=AF_INET, sin_port=htons(20002),
sin_addr=inet_addr("0.0.0.0")}, 16) = 0
sendto(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1242, MSG_FASTOPEN, {sa_family=AF_INET, sin_port=htons(20002),
sin_addr=inet_addr("127.0.0.1")}, 16) = 1242
setsockopt(3, SOL_TCP, TCP_REPAIR_WINDOW,
"\4\0\0@+\205\0\0\377\377\0\0\377\377\377\177\0\0\0\0", 20) = 0
writev(3, [{"\270", 1}], 1) = 1
setsockopt(3, SOL_TCP, TCP_REPAIR_OPTIONS,
"\10\0\0\0\0\0\0\0\0\0\0\0|\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 386) = 0
writev(3,
[{"\210v\r[\226\320t\231qwQ\204\264l\254\t\1\20\245\214p\350H\223\254;\\\37\345\307p$"...,
3144}], 1) = 3144
The 3rd system call looks odd :
setsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [-1], 4) = 0
This patch makes sure bound checking is using an unsigned compare.
Fixes: ee9952831cfd ("tcp: Initial repair mode")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
---
net/ipv4/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index
4b18ad41d4df354b151ef2a05e771cce48dcb5b7..44be7f43455e4aefde8db61e2d941a69abcc642a
100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2674,7 +2674,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
case TCP_REPAIR_QUEUE:
if (!tp->repair)
err = -EPERM;
- else if (val < TCP_QUEUES_NR)
+ else if ((unsigned int)val < TCP_QUEUES_NR)
tp->repair_queue = val;
else
err = -EINVAL;
--
2.17.0.441.gb46fe60e1d-goog
