[PATCH bpf-next 1/2] bpf: make reg_not_null() true for CONST_PTR_TO_MAP

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When reg->type is CONST_PTR_TO_MAP, it can not be null. However the
verifier explores the branches under rX == 0 in check_cond_jmp_op()
even if reg->type is CONST_PTR_TO_MAP, because it was not checked for
in reg_not_null().

Fix this by adding CONST_PTR_TO_MAP to the set of types that are
considered non nullable in reg_not_null().

Signed-off-by: Ihor Solodrai <isolodrai@xxxxxxxx>
---
 kernel/bpf/verifier.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d5807d2efc92..f5e23ec83ef7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -405,7 +405,8 @@ static bool reg_not_null(const struct bpf_reg_state *reg)
 		type == PTR_TO_MAP_KEY ||
 		type == PTR_TO_SOCK_COMMON ||
 		(type == PTR_TO_BTF_ID && is_trusted_reg(reg)) ||
-		type == PTR_TO_MEM;
+		type == PTR_TO_MEM ||
+		type == CONST_PTR_TO_MAP;
 }
 
 static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg)
-- 
2.47.1






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