static_branch_unlikely(&tcp_md5_needed) is enabled by tcp_alloc_md5sig_pool(), so as long as the code doesn't change tcp_md5sig_pool has been already populated if this code is being executed. In case tcptw->tw_md5_key allocaion failed - no reason to crash kernel: tcp_{v4,v6}_send_ack() will send unsigned segment, the connection won't be established, which is bad enough, but in OOM situation totally acceptable and better than kernel crash. Introduce tcp_md5sig_pool_ready() helper. tcp_alloc_md5sig_pool() usage is intentionally avoided here as it's fast-path here and it's check for sanity rather than point of actual pool allocation. That will allow to have generic slow-path allocator for tcp crypto pool. Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx> --- include/net/tcp.h | 1 + net/ipv4/tcp.c | 5 +++++ net/ipv4/tcp_minisocks.c | 5 +++-- 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 4da22b41bde6..3e5423a10a74 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1672,6 +1672,7 @@ tcp_md5_do_lookup(const struct sock *sk, int l3index, #endif bool tcp_alloc_md5sig_pool(void); +bool tcp_md5sig_pool_ready(void); struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); static inline void tcp_put_md5sig_pool(void) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index b7796b4cf0a0..c0856a6af9f5 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4314,6 +4314,11 @@ bool tcp_alloc_md5sig_pool(void) } EXPORT_SYMBOL(tcp_alloc_md5sig_pool); +bool tcp_md5sig_pool_ready(void) +{ + return tcp_md5sig_pool_populated; +} +EXPORT_SYMBOL(tcp_md5sig_pool_ready); /** * tcp_get_md5sig_pool - get md5sig_pool for this user diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index cf913a66df17..c99cdb529902 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -293,11 +293,12 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) tcptw->tw_md5_key = NULL; if (static_branch_unlikely(&tcp_md5_needed)) { struct tcp_md5sig_key *key; + bool err = WARN_ON(!tcp_md5sig_pool_ready()); key = tp->af_specific->md5_lookup(sk, sk); - if (key) { + if (key && !err) { tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC); - BUG_ON(tcptw->tw_md5_key && !tcp_alloc_md5sig_pool()); + WARN_ON_ONCE(tcptw->tw_md5_key == NULL); } } } while (0); -- 2.33.1