From 567da5d253cd6b41c6d015adac1af653725bef9d Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 2 Mar 2023 15:50:00 -0800 Subject: [PATCH] bpf: improve regsafe() checks for PTR_TO_{MEM,BUF,TP_BUFFER} Teach regsafe() logic to handle PTR_TO_MEM, PTR_TO_BUF, and PTR_TO_TP_BUFFER similarly to PTR_TO_MAP_{KEY,VALUE}. That is, instead of exact match for var_off and range, use tnum_in() and range_within() checks, allowing more general verified state to subsume more specific current state. This allows to match wider range of valid and safe states, speeding up verification and detecting wider range of equivalent states for upcoming open-coded iteration looping logic. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20230302235015.2044271-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4f71b6b..b071b92 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -14209,13 +14209,17 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold, tnum_in(rold->var_off, rcur->var_off); case PTR_TO_MAP_KEY: case PTR_TO_MAP_VALUE: + case PTR_TO_MEM: + case PTR_TO_BUF: + case PTR_TO_TP_BUFFER: /* If the new min/max/var_off satisfy the old ones and * everything else matches, we are OK. */ return memcmp(rold, rcur, offsetof(struct bpf_reg_state, var_off)) == 0 && range_within(rold, rcur) && tnum_in(rold->var_off, rcur->var_off) && - check_ids(rold->id, rcur->id, idmap); + check_ids(rold->id, rcur->id, idmap) && + check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap); case PTR_TO_PACKET_META: case PTR_TO_PACKET: /* We must have at least as much range as the old ptr -- 2.7.4