* Patch "net: bpf: reject invalid shifts" has been added to the 4.3-stable tree
@ 2016-01-27 6:29 gregkh
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From: gregkh @ 2016-01-27 6:29 UTC (permalink / raw)
To: rabin, ast, daniel, davem, gregkh; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
net: bpf: reject invalid shifts
to the 4.3-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:
net-bpf-reject-invalid-shifts.patch
and it can be found in the queue-4.3 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 Tue Jan 26 21:35:03 PST 2016
From: Rabin Vincent <rabin@rab.in>
Date: Tue, 12 Jan 2016 20:17:08 +0100
Subject: net: bpf: reject invalid shifts
From: Rabin Vincent <rabin@rab.in>
[ Upstream commit 229394e8e62a4191d592842cf67e80c62a492937 ]
On ARM64, a BUG() is triggered in the eBPF JIT if a filter with a
constant shift that can't be encoded in the immediate field of the
UBFM/SBFM instructions is passed to the JIT. Since these shifts
amounts, which are negative or >= regsize, are invalid, reject them in
the eBPF verifier and the classic BPF filter checker, for all
architectures.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-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 | 10 ++++++++++
net/core/filter.c | 5 +++++
2 files changed, 15 insertions(+)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1058,6 +1058,16 @@ static int check_alu_op(struct reg_state
return -EINVAL;
}
+ if ((opcode == BPF_LSH || opcode == BPF_RSH ||
+ opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
+ int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
+
+ if (insn->imm < 0 || insn->imm >= size) {
+ verbose("invalid shift %d\n", insn->imm);
+ return -EINVAL;
+ }
+ }
+
/* pattern match 'bpf_add Rx, imm' instruction */
if (opcode == BPF_ADD && BPF_CLASS(insn->code) == BPF_ALU64 &&
regs[insn->dst_reg].type == FRAME_PTR &&
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -781,6 +781,11 @@ static int bpf_check_classic(const struc
if (ftest->k == 0)
return -EINVAL;
break;
+ case BPF_ALU | BPF_LSH | BPF_K:
+ case BPF_ALU | BPF_RSH | BPF_K:
+ if (ftest->k >= 32)
+ return -EINVAL;
+ break;
case BPF_LD | BPF_MEM:
case BPF_LDX | BPF_MEM:
case BPF_ST:
Patches currently in stable-queue which might be from rabin@rab.in are
queue-4.3/net-filter-make-jits-zero-a-for-skf_ad_alu_xor_x.patch
queue-4.3/net-bpf-reject-invalid-shifts.patch
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2016-01-27 6:29 Patch "net: bpf: reject invalid shifts" has been added to the 4.3-stable tree gregkh
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