From ee263de7a378e701f15e58879f36fdcfe8742006 Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Mon, 9 Dec 2019 11:53:54 +0100 Subject: conncache: fix multi-thread use of shared connection cache It could accidentally let the connection get used by more than one thread, leading to double-free and more. Reported-by: Christopher Reid Fixes #4544 Closes #4557 --- lib/conncache.h | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'lib/conncache.h') diff --git a/lib/conncache.h b/lib/conncache.h index 58f902409..5fe80b4c8 100644 --- a/lib/conncache.h +++ b/lib/conncache.h @@ -42,6 +42,27 @@ struct conncache { #define BUNDLE_UNKNOWN 0 /* initial value */ #define BUNDLE_MULTIPLEX 2 +#ifdef CURLDEBUG +/* the debug versions of these macros make extra certain that the lock is + never doubly locked or unlocked */ +#define CONN_LOCK(x) if((x)->share) { \ + Curl_share_lock((x), CURL_LOCK_DATA_CONNECT, CURL_LOCK_ACCESS_SINGLE); \ + DEBUGASSERT(!(x)->state.conncache_lock); \ + (x)->state.conncache_lock = TRUE; \ + } + +#define CONN_UNLOCK(x) if((x)->share) { \ + DEBUGASSERT((x)->state.conncache_lock); \ + (x)->state.conncache_lock = FALSE; \ + Curl_share_unlock((x), CURL_LOCK_DATA_CONNECT); \ + } +#else +#define CONN_LOCK(x) if((x)->share) \ + Curl_share_lock((x), CURL_LOCK_DATA_CONNECT, CURL_LOCK_ACCESS_SINGLE) +#define CONN_UNLOCK(x) if((x)->share) \ + Curl_share_unlock((x), CURL_LOCK_DATA_CONNECT) +#endif + struct connectbundle { int multiuse; /* supports multi-use */ size_t num_connections; /* Number of connections in the bundle */ @@ -61,7 +82,8 @@ void Curl_conncache_unlock(struct Curl_easy *data); size_t Curl_conncache_size(struct Curl_easy *data); size_t Curl_conncache_bundle_size(struct connectdata *conn); -bool Curl_conncache_return_conn(struct connectdata *conn); +bool Curl_conncache_return_conn(struct Curl_easy *data, + struct connectdata *conn); CURLcode Curl_conncache_add_conn(struct conncache *connc, struct connectdata *conn) WARN_UNUSED_RESULT; void Curl_conncache_remove_conn(struct Curl_easy *data, -- cgit v1.2.3