From: Paolo Abeni <pabeni@redhat.com> stable inclusion from stable-v6.6.117 commit 49888b3b457b801282b44c246d289c56e2f2a55b category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8681 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 8e04ce45a8db7a080220e86e249198fa676b83dc ] If a MSG_PEEK | MSG_WAITALL read operation consumes all the bytes in the receive queue and recvmsg() need to waits for more data - i.e. it's a blocking one - upon arrival of the next packet the MPTCP protocol will start again copying the oldest data present in the receive queue, corrupting the data stream. Address the issue explicitly tracking the peeked sequence number, restarting from the last peeked byte. Fixes: ca4fb892579f ("mptcp: add MSG_PEEK support") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Geliang Tang <geliang@kernel.org> Tested-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-2-38ffff5a9ec8@k... Signed-off-by: Jakub Kicinski <kuba@kernel.org> [ Adjust context ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Li Xiasong <lixiasong1@huawei.com> --- net/mptcp/protocol.c | 36 +++++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index d720c9f3afee..9517f7d79884 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1957,19 +1957,35 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied); static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, struct msghdr *msg, - size_t len, int flags, + size_t len, int flags, int copied_total, struct scm_timestamping_internal *tss, int *cmsg_flags) { struct sk_buff *skb, *tmp; + int total_data_len = 0; int copied = 0; skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { - u32 offset = MPTCP_SKB_CB(skb)->offset; + u32 delta, offset = MPTCP_SKB_CB(skb)->offset; u32 data_len = skb->len - offset; - u32 count = min_t(size_t, len - copied, data_len); + u32 count; int err; + if (flags & MSG_PEEK) { + /* skip already peeked skbs */ + if (total_data_len + data_len <= copied_total) { + total_data_len += data_len; + continue; + } + + /* skip the already peeked data in the current skb */ + delta = copied_total - total_data_len; + offset += delta; + data_len -= delta; + } + + count = min_t(size_t, len - copied, data_len); + if (!(flags & MSG_TRUNC)) { err = skb_copy_datagram_msg(skb, offset, msg, count); if (unlikely(err < 0)) { @@ -1986,22 +2002,19 @@ static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, copied += count; - if (count < data_len) { - if (!(flags & MSG_PEEK)) { + if (!(flags & MSG_PEEK)) { + msk->bytes_consumed += count; + if (count < data_len) { MPTCP_SKB_CB(skb)->offset += count; MPTCP_SKB_CB(skb)->map_seq += count; - msk->bytes_consumed += count; + break; } - break; - } - if (!(flags & MSG_PEEK)) { /* we will bulk release the skb memory later */ skb->destructor = NULL; WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize); __skb_unlink(skb, &msk->receive_queue); __kfree_skb(skb); - msk->bytes_consumed += count; } if (copied >= len) @@ -2225,7 +2238,8 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, while (copied < len) { int err, bytes_read; - bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); + bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, + copied, &tss, &cmsg_flags); if (unlikely(bytes_read < 0)) { if (!copied) copied = bytes_read; -- 2.34.1