Patch "bpf/verifier: reject invalid LD_ABS | BPF_DW instruction" has been added to the 4.4-stable tree

Patch "bpf/verifier: reject invalid LD_ABS | BPF_DW instruction" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    bpf/verifier: reject invalid LD_ABS | BPF_DW instruction

to the 4.4-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-verifier-reject-invalid-ld_abs-bpf_dw-instruction.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon May 16 11:21:32 PDT 2016
From: Alexei Starovoitov <ast@fb.com>
Date: Tue, 12 Apr 2016 10:26:19 -0700
Subject: bpf/verifier: reject invalid LD_ABS | BPF_DW instruction

From: Alexei Starovoitov <ast@fb.com>

[ Upstream commit d82bccc69041a51f7b7b9b4a36db0772f4cdba21 ]

verifier must check for reserved size bits in instruction opcode and
reject BPF_LD | BPF_ABS | BPF_DW and BPF_LD | BPF_IND | BPF_DW instructions,
otherwise interpreter will WARN_RATELIMIT on them during execution.

Fixes: ddd872bc3098 ("bpf: verifier: add checks for BPF_ABS | BPF_IND instructions")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/bpf/verifier.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1348,6 +1348,7 @@ static int check_ld_abs(struct verifier_
 	}
 
 	if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
+	    BPF_SIZE(insn->code) == BPF_DW ||
 	    (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
 		verbose("BPF_LD_ABS uses reserved fields\n");
 		return -EINVAL;


Patches currently in stable-queue which might be from ast@fb.com are

queue-4.4/samples-bpf-fix-trace_output-example.patch
queue-4.4/bpf-fix-refcnt-overflow.patch
queue-4.4/bpf-verifier-reject-invalid-ld_abs-bpf_dw-instruction.patch
queue-4.4/bpf-fix-check_map_func_compatibility-logic.patch