diff options
author | Jakub Kicinski <kuba@kernel.org> | 2021-09-01 10:55:51 -0700 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2021-09-01 10:55:51 -0700 |
commit | 36e784a60b85eb41a34b3232e95bf111931b9b09 (patch) | |
tree | 306543d6fd15ed7268a931143ea5c74c77a46eb4 | |
parent | 780aa1209f88fd96d40572b62df922662f2b896d (diff) | |
parent | bfd862a7e9318dd906844807a713d27cdd1a72b1 (diff) | |
download | linux-36e784a60b85eb41a34b3232e95bf111931b9b09.tar.bz2 |
Merge branch 'mptcp-prevent-tcp_push-crash-and-selftest-temp-file-buildup'
Mat Martineau says:
====================
mptcp: Prevent tcp_push() crash and selftest temp file buildup
These are two fixes for the net tree, addressing separate issues.
Patch 1 addresses a divide-by-zero crash seen in syzkaller and also
reported by a user on the netdev list. This changes MPTCP code so
tcp_push() cannot be called with an invalid (0) mss_now value.
Patch 2 fixes a selftest temp file cleanup issue that consumes excessive
disk space when running repeated tests.
====================
Link: https://lore.kernel.org/r/20210901171537.121255-1-mathew.j.martineau@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r-- | net/mptcp/protocol.c | 76 | ||||
-rwxr-xr-x | tools/testing/selftests/net/mptcp/simult_flows.sh | 4 |
2 files changed, 37 insertions, 43 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index ade648c3512b..a4c6e37e07c9 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1003,6 +1003,13 @@ static void mptcp_wmem_uncharge(struct sock *sk, int size) msk->wmem_reserved += size; } +static void __mptcp_mem_reclaim_partial(struct sock *sk) +{ + lockdep_assert_held_once(&sk->sk_lock.slock); + __mptcp_update_wmem(sk); + sk_mem_reclaim_partial(sk); +} + static void mptcp_mem_reclaim_partial(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); @@ -1094,12 +1101,8 @@ static void __mptcp_clean_una(struct sock *sk) msk->recovery = false; out: - if (cleaned) { - if (tcp_under_memory_pressure(sk)) { - __mptcp_update_wmem(sk); - sk_mem_reclaim_partial(sk); - } - } + if (cleaned && tcp_under_memory_pressure(sk)) + __mptcp_mem_reclaim_partial(sk); if (snd_una == READ_ONCE(msk->snd_nxt) && !msk->recovery) { if (mptcp_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) @@ -1179,6 +1182,7 @@ struct mptcp_sendmsg_info { u16 limit; u16 sent; unsigned int flags; + bool data_lock_held; }; static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq, @@ -1250,17 +1254,17 @@ static bool __mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) return false; } -static bool mptcp_must_reclaim_memory(struct sock *sk, struct sock *ssk) +static bool mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held) { - return !ssk->sk_tx_skb_cache && - tcp_under_memory_pressure(sk); -} + gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation; -static bool mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk) -{ - if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) - mptcp_mem_reclaim_partial(sk); - return __mptcp_alloc_tx_skb(sk, ssk, sk->sk_allocation); + if (unlikely(tcp_under_memory_pressure(sk))) { + if (data_lock_held) + __mptcp_mem_reclaim_partial(sk); + else + mptcp_mem_reclaim_partial(sk); + } + return __mptcp_alloc_tx_skb(sk, ssk, gfp); } /* note: this always recompute the csum on the whole skb, even @@ -1284,7 +1288,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, bool zero_window_probe = false; struct mptcp_ext *mpext = NULL; struct sk_buff *skb, *tail; - bool can_collapse = false; + bool must_collapse = false; int size_bias = 0; int avail_size; size_t ret = 0; @@ -1304,16 +1308,24 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, * SSN association set here */ mpext = skb_ext_find(skb, SKB_EXT_MPTCP); - can_collapse = (info->size_goal - skb->len > 0) && - mptcp_skb_can_collapse_to(data_seq, skb, mpext); - if (!can_collapse) { + if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) { TCP_SKB_CB(skb)->eor = 1; - } else { + goto alloc_skb; + } + + must_collapse = (info->size_goal - skb->len > 0) && + (skb_shinfo(skb)->nr_frags < sysctl_max_skb_frags); + if (must_collapse) { size_bias = skb->len; avail_size = info->size_goal - skb->len; } } +alloc_skb: + if (!must_collapse && !ssk->sk_tx_skb_cache && + !mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held)) + return 0; + /* Zero window and all data acked? Probe. */ avail_size = mptcp_check_allowed_size(msk, data_seq, avail_size); if (avail_size == 0) { @@ -1343,7 +1355,6 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, if (skb == tail) { TCP_SKB_CB(tail)->tcp_flags &= ~TCPHDR_PSH; mpext->data_len += ret; - WARN_ON_ONCE(!can_collapse); WARN_ON_ONCE(zero_window_probe); goto out; } @@ -1530,15 +1541,6 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags) if (ssk != prev_ssk) lock_sock(ssk); - /* keep it simple and always provide a new skb for the - * subflow, even if we will not use it when collapsing - * on the pending one - */ - if (!mptcp_alloc_tx_skb(sk, ssk)) { - mptcp_push_release(sk, ssk, &info); - goto out; - } - ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); if (ret <= 0) { mptcp_push_release(sk, ssk, &info); @@ -1571,7 +1573,9 @@ out: static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk) { struct mptcp_sock *msk = mptcp_sk(sk); - struct mptcp_sendmsg_info info; + struct mptcp_sendmsg_info info = { + .data_lock_held = true, + }; struct mptcp_data_frag *dfrag; struct sock *xmit_ssk; int len, copied = 0; @@ -1597,13 +1601,6 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk) goto out; } - if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) { - __mptcp_update_wmem(sk); - sk_mem_reclaim_partial(sk); - } - if (!__mptcp_alloc_tx_skb(sk, ssk, GFP_ATOMIC)) - goto out; - ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); if (ret <= 0) goto out; @@ -2409,9 +2406,6 @@ static void __mptcp_retrans(struct sock *sk) info.sent = 0; info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent; while (info.sent < info.limit) { - if (!mptcp_alloc_tx_skb(sk, ssk)) - break; - ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); if (ret <= 0) break; diff --git a/tools/testing/selftests/net/mptcp/simult_flows.sh b/tools/testing/selftests/net/mptcp/simult_flows.sh index fd63ebfe9a2b..910d8126af8f 100755 --- a/tools/testing/selftests/net/mptcp/simult_flows.sh +++ b/tools/testing/selftests/net/mptcp/simult_flows.sh @@ -22,8 +22,8 @@ usage() { cleanup() { - rm -f "$cin" "$cout" - rm -f "$sin" "$sout" + rm -f "$cout" "$sout" + rm -f "$large" "$small" rm -f "$capout" local netns |