This is a note to let you know that I've just added the patch titled
arm64: bpf: fix out-of-bounds read in bpf2a64_offset()
to the 4.1-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:
arm64-bpf-fix-out-of-bounds-read-in-bpf2a64_offset.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8eee539ddea09bccae2426f09b0ba6a18b72b691 Mon Sep 17 00:00:00 2001
From: Xi Wang <xi.wang@xxxxxxxxx>
Date: Thu, 25 Jun 2015 05:47:39 -0700
Subject: arm64: bpf: fix out-of-bounds read in bpf2a64_offset()
From: Xi Wang <xi.wang@xxxxxxxxx>
commit 8eee539ddea09bccae2426f09b0ba6a18b72b691 upstream.
Problems occur when bpf_to or bpf_from has value prog->len - 1 (e.g.,
"Very long jump backwards" in test_bpf where the last instruction is a
jump): since ctx->offset has length prog->len, ctx->offset[bpf_to + 1]
or ctx->offset[bpf_from + 1] will cause an out-of-bounds read, leading
to a bogus jump offset and kernel panic.
This patch moves updating ctx->offset to after calling build_insn(),
and changes indexing to use bpf_to and bpf_from without + 1.
Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler")
Cc: Zi Shen Lim <zlim.lnx@xxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Signed-off-by: Xi Wang <xi.wang@xxxxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/net/bpf_jit_comp.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -113,9 +113,9 @@ static inline void emit_a64_mov_i(const
static inline int bpf2a64_offset(int bpf_to, int bpf_from,
const struct jit_ctx *ctx)
{
- int to = ctx->offset[bpf_to + 1];
+ int to = ctx->offset[bpf_to];
/* -1 to account for the Branch instruction */
- int from = ctx->offset[bpf_from + 1] - 1;
+ int from = ctx->offset[bpf_from] - 1;
return to - from;
}
@@ -640,10 +640,11 @@ static int build_body(struct jit_ctx *ct
const struct bpf_insn *insn = &prog->insnsi[i];
int ret;
+ ret = build_insn(insn, ctx);
+
if (ctx->image == NULL)
ctx->offset[i] = ctx->idx;
- ret = build_insn(insn, ctx);
if (ret > 0) {
i++;
continue;
Patches currently in stable-queue which might be from xi.wang@xxxxxxxxx are
queue-4.1/arm64-bpf-fix-endianness-conversion-bugs.patch
queue-4.1/arm64-bpf-fix-out-of-bounds-read-in-bpf2a64_offset.patch
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