From 61c0b0d0f199589c72bd53e267d797a8e4bf1478 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 14 Aug 2024 20:03:33 +1000 Subject: [PATCH] flow: Don't crash if guest attempts to connect to port 0 Using a zero port on TCP or UDP is dubious, and we can't really deal with forwarding such a flow within the constraints of the socket API. Hence we ASSERT()ed that we had non-zero ports in flow_hash(). The intention was to make sure that the protocol code sanitizes such ports before completing a flow entry. Unfortunately, flow_hash() is also called on new packets to see if they have an existing flow, so the unsanitized guest packet can crash passt with the assert. Correct this by moving the assert from flow_hash() to flow_sidx_hash() which is only used on entries already in the table, not on unsanitized data. Reported-by: Matt Hamilton Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- flow.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/flow.c b/flow.c index 687e9fd..93b687d 100644 --- a/flow.c +++ b/flow.c @@ -561,12 +561,6 @@ static uint64_t flow_hash(const struct ctx *c, uint8_t proto, uint8_t pif, { struct siphash_state state = SIPHASH_INIT(c->hash_secret); - /* For the hash table to work, we need complete endpoint information, - * and at least a forwarding port. - */ - ASSERT(pif != PIF_NONE && !inany_is_unspecified(&side->eaddr) && - side->eport != 0 && side->fport != 0); - inany_siphash_feed(&state, &side->faddr); inany_siphash_feed(&state, &side->eaddr); @@ -586,8 +580,16 @@ static uint64_t flow_hash(const struct ctx *c, uint8_t proto, uint8_t pif, static uint64_t flow_sidx_hash(const struct ctx *c, flow_sidx_t sidx) { const struct flow_common *f = &flow_at_sidx(sidx)->f; - return flow_hash(c, FLOW_PROTO(f), - f->pif[sidx.sidei], &f->side[sidx.sidei]); + const struct flowside *side = &f->side[sidx.sidei]; + uint8_t pif = f->pif[sidx.sidei]; + + /* For the hash table to work, entries must have complete endpoint + * information, and at least a forwarding port. + */ + ASSERT(pif != PIF_NONE && !inany_is_unspecified(&side->eaddr) && + side->eport != 0 && side->fport != 0); + + return flow_hash(c, FLOW_PROTO(f), pif, side); } /**