Commmits 57a09bf0a416 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers") and 484611357c19 ("bpf: allow access into map value arrays") by themselves are correct, but in combination they make state equivalence ignore 'id' field of the register state which can lead to accepting invalid program.

Fixes 57a09bf0a416 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers")

Fixes 484611357c19 ("bpf: allow access into map value arrays")

Signed-off-by Alexei Starovoitov <[email protected]>

Acked-by Daniel Borkmann <[email protected]>

Acked-by Thomas Graf <[email protected]>

Signed-off-by David S. Miller <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 include/linux/bpf_verifier.h |   14 +++++++-------
 kernel/bpf/verifier.c        |    2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)

include/linux/bpf_verifier.h +7 -7

@@ -18,13 +18,6 @@
 
 struct bpf_reg_state {
 	enum bpf_reg_type type;
-	/*
-	 * Used to determine if any memory access using this register will
-	 * result in a bad access.
-	 */
-	s64 min_value;
-	u64 max_value;
-	u32 id;
 	union {
 		/* valid when type == CONST_IMM | PTR_TO_STACK | UNKNOWN_VALUE */
 		s64 imm;

@@ -40,6 +33,13 @@ struct bpf_reg_state {
 		 */
 		struct bpf_map *map_ptr;
 	};
+	u32 id;
+	/* Used to determine if any memory access using this register will
+	 * result in a bad access. These two fields must be last.
+	 * See states_equal()
+	 */
+	s64 min_value;
+	u64 max_value;
 };
 
 enum bpf_stack_slot_type {

kernel/bpf/verifier.c +1 -1

@@ -2498,7 +2498,7 @@ static bool states_equal(struct bpf_veri
 		 * we didn't do a variable access into a map then we are a-ok.
 		 */
 		if (!varlen_map_access &&
-		    rold->type == rcur->type && rold->imm == rcur->imm)
+		    memcmp(rold, rcur, offsetofend(struct bpf_reg_state, id)) == 0)
 			continue;
 
 		/* If we didn't map access then again we don't care about the

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/bpf-fix-state-equivalence.patch