This is a note to let you know that I've just added the patch titled bpf: fix state equivalence to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-fix-state-equivalence.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sat Mar 18 22:03:25 CST 2017 From: Alexei Starovoitov <ast@xxxxxx> Date: Wed, 7 Dec 2016 10:57:59 -0800 Subject: bpf: fix state equivalence From: Alexei Starovoitov <ast@xxxxxx> [ Upstream commit d2a4dd37f6b41fbcad76efbf63124eb3126c66fe ] 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 <ast@xxxxxxxxxx> Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Acked-by: Thomas Graf <tgraf@xxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/linux/bpf_verifier.h | 14 +++++++------- kernel/bpf/verifier.c | 2 +- 2 files changed, 8 insertions(+), 8 deletions(-) --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -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 { --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -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 ast@xxxxxx are queue-4.9/bpf-fix-state-equivalence.patch