2018-01-06 17:13:39 +03:00
|
|
|
From 652c6cabaf30e4c75f7dc2c42a33a8f066d7df2c Mon Sep 17 00:00:00 2001
|
|
|
|
|
From: Jann Horn <jannh@google.com>
|
|
|
|
|
Date: Thu, 4 Jan 2018 08:01:22 -0600
|
2018-01-08 12:25:09 +03:00
|
|
|
Subject: [PATCH 227/241] bpf: fix incorrect sign extension in check_alu_op()
|
2018-01-06 17:13:39 +03:00
|
|
|
MIME-Version: 1.0
|
|
|
|
|
Content-Type: text/plain; charset=UTF-8
|
|
|
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
|
|
|
|
|
|
[ Upstream commit 95a762e2c8c942780948091f8f2a4f32fce1ac6f ]
|
|
|
|
|
|
|
|
|
|
Distinguish between
|
|
|
|
|
BPF_ALU64|BPF_MOV|BPF_K (load 32-bit immediate, sign-extended to 64-bit)
|
|
|
|
|
and BPF_ALU|BPF_MOV|BPF_K (load 32-bit immediate, zero-padded to 64-bit);
|
|
|
|
|
only perform sign extension in the first case.
|
|
|
|
|
|
|
|
|
|
Starting with v4.14, this is exploitable by unprivileged users as long as
|
|
|
|
|
the unprivileged_bpf_disabled sysctl isn't set.
|
|
|
|
|
|
|
|
|
|
Debian assigned CVE-2017-16995 for this issue.
|
|
|
|
|
|
|
|
|
|
v3:
|
|
|
|
|
- add CVE number (Ben Hutchings)
|
|
|
|
|
|
|
|
|
|
Fixes: 484611357c19 ("bpf: allow access into map value arrays")
|
|
|
|
|
Signed-off-by: Jann Horn <jannh@google.com>
|
|
|
|
|
Acked-by: Edward Cree <ecree@solarflare.com>
|
|
|
|
|
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
|
|
|
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
|
|
|
|
|
CVE-2017-16995
|
|
|
|
|
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
|
|
|
|
|
Signed-off-by: Andy Whitcroft <apw@canonical.com>
|
|
|
|
|
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
|
|
|
|
|
(cherry picked from commit 868c88129c7567525dbde3cb6989a5acd478bd80)
|
|
|
|
|
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
|
|
|
|
|
---
|
|
|
|
|
kernel/bpf/verifier.c | 15 +++++++++++----
|
|
|
|
|
1 file changed, 11 insertions(+), 4 deletions(-)
|
|
|
|
|
|
|
|
|
|
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
|
|
|
|
|
index 4321625fe32a..cdfa07a4ef27 100644
|
|
|
|
|
--- a/kernel/bpf/verifier.c
|
|
|
|
|
+++ b/kernel/bpf/verifier.c
|
|
|
|
|
@@ -2048,12 +2048,19 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
|
|
|
|
|
/* case: R = imm
|
|
|
|
|
* remember the value we stored into this reg
|
|
|
|
|
*/
|
|
|
|
|
+ u64 imm;
|
|
|
|
|
+
|
|
|
|
|
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
|
|
|
|
|
+ imm = insn->imm;
|
|
|
|
|
+ else
|
|
|
|
|
+ imm = (u32)insn->imm;
|
|
|
|
|
+
|
|
|
|
|
regs[insn->dst_reg].type = CONST_IMM;
|
|
|
|
|
- regs[insn->dst_reg].imm = insn->imm;
|
|
|
|
|
+ regs[insn->dst_reg].imm = imm;
|
|
|
|
|
regs[insn->dst_reg].id = 0;
|
|
|
|
|
- regs[insn->dst_reg].max_value = insn->imm;
|
|
|
|
|
- regs[insn->dst_reg].min_value = insn->imm;
|
|
|
|
|
- regs[insn->dst_reg].min_align = calc_align(insn->imm);
|
|
|
|
|
+ regs[insn->dst_reg].max_value = imm;
|
|
|
|
|
+ regs[insn->dst_reg].min_value = imm;
|
|
|
|
|
+ regs[insn->dst_reg].min_align = calc_align(imm);
|
|
|
|
|
regs[insn->dst_reg].value_from_signed = false;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
--
|
|
|
|
|
2.14.2
|
|
|
|
|
|
