From b4ff6f4ae9267620827f7da9b519f4e1b28b10e9 Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Fri, 24 Dec 2021 13:38:49 +0100 Subject: [PATCH] BUG/MEDIUM: peers: properly skip conn_cur from incoming messages The approach used for skipping conn_cur in commit db2ab8218 ("MEDIUM: stick-table: never learn the "conn_cur" value from peers") was wrong, it only works with simple tables but as soon as frequency counters or arrays are exchanged after conn_cur, the stream is desynchronized and incorrect values are read. This is because the fields have a variable length depending on their types and cannot simply be skipped by a "continue" statement. Let's change the approach to make sure we continue to completely parse these local-only fields, and only drop the value at the moment we're about to store them, since this is exactly the intent. A simpler approach could consist in having two sets of stktable_data_ptr() functions, one for retrieval and one for storage, and to make the store function return a NULL pointer for local types. For now this doesn't seem worth the trouble. This fixes github issue #1497. Thanks to @brenc for the reproducer. This must be backported to 2.5. --- src/peers.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/src/peers.c b/src/peers.c index 5cd2f74580..deb5a89f39 100644 --- a/src/peers.c +++ b/src/peers.c @@ -1774,12 +1774,12 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, for (data_type = 0 ; data_type < STKTABLE_DATA_TYPES ; data_type++) { uint64_t decoded_int; unsigned int idx; + int ignore; if (!((1ULL << data_type) & st->remote_data)) continue; - if (stktable_data_types[data_type].is_local) - continue; + ignore = stktable_data_types[data_type].is_local; if (stktable_data_types[data_type].is_array) { /* in case of array all elements @@ -1798,7 +1798,7 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, } data_ptr = stktable_data_ptr_idx(st->table, ts, data_type, idx); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_sint) = decoded_int; } break; @@ -1811,7 +1811,7 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, } data_ptr = stktable_data_ptr_idx(st->table, ts, data_type, idx); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_uint) = decoded_int; } break; @@ -1824,7 +1824,7 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, } data_ptr = stktable_data_ptr_idx(st->table, ts, data_type, idx); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_ull) = decoded_int; } break; @@ -1858,7 +1858,7 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, } data_ptr = stktable_data_ptr_idx(st->table, ts, data_type, idx); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_frqp) = data; } break; @@ -1878,19 +1878,19 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, switch (stktable_data_types[data_type].std_type) { case STD_T_SINT: data_ptr = stktable_data_ptr(st->table, ts, data_type); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_sint) = decoded_int; break; case STD_T_UINT: data_ptr = stktable_data_ptr(st->table, ts, data_type); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_uint) = decoded_int; break; case STD_T_ULL: data_ptr = stktable_data_ptr(st->table, ts, data_type); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_ull) = decoded_int; break; @@ -1917,7 +1917,7 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, } data_ptr = stktable_data_ptr(st->table, ts, data_type); - if (data_ptr) + if (data_ptr && !ignore) stktable_data_cast(data_ptr, std_t_frqp) = data; break; } @@ -1986,7 +1986,7 @@ static int peer_treat_updatemsg(struct appctx *appctx, struct peer *p, int updt, } if (de) { data_ptr = stktable_data_ptr(st->table, ts, data_type); - if (data_ptr) { + if (data_ptr && !ignore) { HA_ATOMIC_INC(&de->refcount); stktable_data_cast(data_ptr, std_t_dict) = de; }