From: Florent Revest <revest@chromium.org>
Date: Thu, 22 Apr 2021 23:55:43 +0000 (+0200)
Subject: bpf: Remove unnecessary map checks for ARG_PTR_TO_CONST_STR
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a8fad73e3334151196acb28c4dcde37732c82542;p=linux.git

bpf: Remove unnecessary map checks for ARG_PTR_TO_CONST_STR

reg->type is enforced by check_reg_type() and map should never be NULL
(it would already have been dereferenced anyway) so these checks are
unnecessary.

Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210422235543.4007694-3-revest@chromium.org
---

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 59799a9b014aa..2579f6fbb5c31 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5075,8 +5075,7 @@ skip_type_check:
 		u64 map_addr;
 		char *str_ptr;
 
-		if (reg->type != PTR_TO_MAP_VALUE || !map ||
-		    !bpf_map_is_rdonly(map)) {
+		if (!bpf_map_is_rdonly(map)) {
 			verbose(env, "R%d does not point to a readonly map'\n", regno);
 			return -EACCES;
 		}