Commit 47f42ff521b4 for kernel
commit 47f42ff521b4eeb46e82f9a46a4783a99f7570d7
Author: Cen Zhang (Microsoft) <blbllhy@gmail.com>
Date: Mon Jul 20 17:41:03 2026 -0400
tipc: fix integer overflow in tipc_recvmsg() and tipc_recvstream()
In tipc_recvmsg(), the copy length is computed as:
copy = min_t(int, dlen - offset, buflen);
buflen is size_t but min_t(int, ...) casts it to int. When buflen
exceeds INT_MAX (e.g. 0xFFFFFFFF via io_uring provided buffers), it
wraps negative, wins the comparison, and the negative copy length
propagates to simple_copy_to_iter() where int-to-size_t promotion
makes it SIZE_MAX, triggering a WARN_ON. tipc_recvstream() has the
same pattern.
Kernel panic - not syncing: kernel: panic_on_warn set ...
RIP: 0010:simple_copy_to_iter+0x9e/0xd0 (net/core/datagram.c:521)
Call Trace:
__skb_datagram_iter+0x123/0x8b0 (net/core/datagram.c:402)
skb_copy_datagram_iter+0x77/0x1a0 (net/core/datagram.c:534)
tipc_recvmsg+0x3d7/0xe80 (net/tipc/socket.c:1934)
io_recvmsg+0x47e/0xda0
Fix by changing min_t(int, ...) to min_t(size_t, ...) in both
functions. The result is always <= (dlen - offset), which is bounded
by TIPC maximum message size (0x1ffff bytes), so the implicit
narrowing on assignment to int copy is always safe.
Fixes: e9f8b10101c6 ("tipc: refactor function tipc_sk_recvmsg()")
Fixes: ec8a09fbbeff ("tipc: refactor function tipc_sk_recv_stream()")
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Cen Zhang (Microsoft) <blbllhy@gmail.com>
Reviewed-by: Tung Nguyen <tung.quang.nguyen@est.tech>
Link: https://patch.msgid.link/20260720214103.47732-1-blbllhy@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 55e695748332..185c24003b82 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1936,7 +1936,7 @@ static int tipc_recvmsg(struct socket *sock, struct msghdr *m,
if (likely(!err)) {
int offset = skb_cb->bytes_read;
- copy = min_t(int, dlen - offset, buflen);
+ copy = min_t(size_t, dlen - offset, buflen);
rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy);
if (unlikely(rc))
goto exit;
@@ -2068,7 +2068,7 @@ static int tipc_recvstream(struct socket *sock, struct msghdr *m,
/* Copy data if msg ok, otherwise return error/partial data */
if (likely(!err)) {
offset = skb_cb->bytes_read;
- copy = min_t(int, dlen - offset, buflen - copied);
+ copy = min_t(size_t, dlen - offset, buflen - copied);
rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy);
if (unlikely(rc))
break;