kernel/linux.git/net/x25, branch v6.6.148

net/x25: fix use-after-free in x25_kill_by_neigh()

2026-08-03T09:15:30+00:00

commit 5499e0602d2faafd42c580d25f615903c3fbe11b upstream. x25_kill_by_neigh() walks the global X.25 socket list looking for sockets attached to a terminating neighbour. x25_list_lock protects list membership while the lookup is in progress, but it does not pin a socket's lifetime after the lock is dropped. The function currently drops x25_list_lock before calling lock_sock(s). A concurrent close can run x25_release(), remove the same socket from x25_list, and drop the last socket reference in that window. The neighbour teardown path can then lock or inspect a freed struct sock/struct x25_sock. Take sock_hold(s) while x25_list_lock still proves that the list entry is live, then drop the temporary reference after the socket has been locked, rechecked, and released. Recheck x25_sk(s)->neighbour after lock_sock(), because another path may have disconnected the socket before this path acquired the socket lock. Restart the list walk after each disconnect because the list lock was dropped and the previous iterator state may no longer be valid. A QEMU/KASAN run against origin/master reproduced a slab-use-after-free in x25_kill_by_neigh(). Fixes: 7781607938c8 ("net/x25: Fix null-ptr-deref caused by x25_disconnect") Cc: stable@vger.kernel.org Signed-off-by: David Lee Assisted-by: Codex:gpt-5.5 Acked-by: Martin Schiller Link: https://patch.msgid.link/20260713104752.241175-1-david.lee@trailofbits.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

net/x25: Fix overflow when accumulating packets

2026-04-11T12:19:24+00:00

[ Upstream commit a1822cb524e89b4cd2cf0b82e484a2335496a6d9 ] Add a check to ensure that `x25_sock.fraglen` does not overflow. The `fraglen` also needs to be resetted when purging `fragment_queue` in `x25_clear_queues()`. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Suggested-by: Yiming Qian Signed-off-by: Martin Schiller Link: https://patch.msgid.link/20260331-x25_fraglen-v4-2-3e69f18464b4@dev.tdt.de Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net/x25: Fix potential double free of skb

2026-04-11T12:19:24+00:00

[ Upstream commit d10a26aa4d072320530e6968ef945c8c575edf61 ] When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at line 48 and returns 1 (error). This error propagates back through the call chain: x25_queue_rx_frame returns 1 | v x25_state3_machine receives the return value 1 and takes the else branch at line 278, setting queued=0 and returning 0 | v x25_process_rx_frame returns queued=0 | v x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb) again This would free the same skb twice. Looking at x25_backlog_rcv: net/x25/x25_in.c:x25_backlog_rcv() { ... queued = x25_process_rx_frame(sk, skb); ... if (!queued) kfree_skb(skb); } Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Martin Schiller Link: https://patch.msgid.link/20260331-x25_fraglen-v4-1-3e69f18464b4@dev.tdt.de Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net/x25: fix incorrect parameter validation in the x25_getsockopt() function

2024-03-26T22:19:41+00:00

[ Upstream commit d6eb8de2015f0c24822e47356f839167ebde2945 ] The 'len' variable can't be negative when assigned the result of 'min_t' because all 'min_t' parameters are cast to unsigned int, and then the minimum one is chosen. To fix the logic, check 'len' as read from 'optlen', where the types of relevant variables are (signed) int. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Gavrilov Ilia Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES)

2023-06-24T22:50:13+00:00

Remove ->sendpage() and ->sendpage_locked(). sendmsg() with MSG_SPLICE_PAGES should be used instead. This allows multiple pages and multipage folios to be passed through. Signed-off-by: David Howells Acked-by: Marc Kleine-Budde # for net/can cc: Jens Axboe cc: Matthew Wilcox cc: linux-afs@lists.infradead.org cc: mptcp@lists.linux.dev cc: rds-devel@oss.oracle.com cc: tipc-discussion@lists.sourceforge.net cc: virtualization@lists.linux-foundation.org Link: https://lore.kernel.org/r/20230623225513.2732256-16-dhowells@redhat.com Signed-off-by: Jakub Kicinski

net/x25: Fix to not accept on connected socket

2023-01-25T09:51:04+00:00

When listen() and accept() are called on an x25 socket that connect() succeeds, accept() succeeds immediately. This is because x25_connect() queues the skb to sk->sk_receive_queue, and x25_accept() dequeues it. This creates a child socket with the sk of the parent x25 socket, which can cause confusion. Fix x25_listen() to return -EINVAL if the socket has already been successfully connect()ed to avoid this issue. Signed-off-by: Hyunwoo Kim Signed-off-by: David S. Miller

net/x25: Fix skb leak in x25_lapb_receive_frame()

2022-11-16T04:22:19+00:00

x25_lapb_receive_frame() using skb_copy() to get a private copy of skb, the new skb should be freed in the undersized/fragmented skb error handling path. Otherwise there is a memory leak. Fixes: cb101ed2c3c7 ("x25: Handle undersized/fragmented skbs") Signed-off-by: Wei Yongjun Acked-by: Martin Schiller Link: https://lore.kernel.org/r/20221114110519.514538-1-weiyongjun@huaweicloud.com Signed-off-by: Jakub Kicinski

net/x25: fix call timeouts in blocking connects

2022-08-09T03:48:51+00:00

When a userspace application starts a blocking connect(), a CALL REQUEST is sent, the t21 timer is started and the connect is waiting in x25_wait_for_connection_establishment(). If then for some reason the t21 timer expires before any reaction on the assigned logical channel (e.g. CALL ACCEPT, CLEAR REQUEST), there is sent a CLEAR REQUEST and timer t23 is started waiting for a CLEAR confirmation. If we now receive a CLEAR CONFIRMATION from the peer, x25_disconnect() is called in x25_state2_machine() with reason "0", which means "normal" call clearing. This is ok, but the parameter "reason" is used as sk->sk_err in x25_disconnect() and sock_error(sk) is evaluated in x25_wait_for_connection_establishment() to check if the call is still pending. As "0" is not rated as an error, the connect will stuck here forever. To fix this situation, also check if the sk->sk_state changed form TCP_SYN_SENT to TCP_CLOSE in the meantime, which is also done by x25_disconnect(). Signed-off-by: Martin Schiller Link: https://lore.kernel.org/r/20220805061810.10824-1-ms@dev.tdt.de Signed-off-by: Jakub Kicinski

x25: remove redundant pointer dev

2022-05-10T09:59:22+00:00

Pointer dev is being assigned a value that is never used, the assignment and the variable are redundant and can be removed. Also replace null check with the preferred !ptr idiom. Cleans up clang scan warning: net/x25/x25_proc.c:94:26: warning: Although the value stored to 'dev' is used in the enclosing expression, the value is never actually read from 'dev' [deadcode.DeadStores] Signed-off-by: Colin Ian King Link: https://lore.kernel.org/r/20220508214500.60446-1-colin.i.king@gmail.com Signed-off-by: Paolo Abeni

net: remove noblock parameter from skb_recv_datagram()

2022-04-06T12:45:26+00:00

skb_recv_datagram() has two parameters 'flags' and 'noblock' that are merged inside skb_recv_datagram() by 'flags | (noblock ? MSG_DONTWAIT : 0)' As 'flags' may contain MSG_DONTWAIT as value most callers split the 'flags' into 'flags' and 'noblock' with finally obsolete bit operations like this: skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &rc); And this is not even done consistently with the 'flags' parameter. This patch removes the obsolete and costly splitting into two parameters and only performs bit operations when really needed on the caller side. One missing conversion thankfully reported by kernel test robot. I missed to enable kunit tests to build the mctp code. Reported-by: kernel test robot Signed-off-by: Oliver Hartkopp Signed-off-by: David S. Miller