projects / pve-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 321d628a FG |
1 | From 652c6cabaf30e4c75f7dc2c42a33a8f066d7df2c Mon Sep 17 00:00:00 2001 |
| 2 | From: Jann Horn <jannh@google.com> | |
| 3 | Date: Thu, 4 Jan 2018 08:01:22 -0600 | |
| e4cdf2a5 | 4 | Subject: [PATCH 227/241] bpf: fix incorrect sign extension in check_alu_op() |
| 321d628a FG |
5 | MIME-Version: 1.0 |
| 6 | Content-Type: text/plain; charset=UTF-8 | |
| 7 | Content-Transfer-Encoding: 8bit | |
| 8 | ||
| 9 | [ Upstream commit 95a762e2c8c942780948091f8f2a4f32fce1ac6f ] | |
| 10 | ||
| 11 | Distinguish between | |
| 12 | BPF_ALU64|BPF_MOV|BPF_K (load 32-bit immediate, sign-extended to 64-bit) | |
| 13 | and BPF_ALU|BPF_MOV|BPF_K (load 32-bit immediate, zero-padded to 64-bit); | |
| 14 | only perform sign extension in the first case. | |
| 15 | ||
| 16 | Starting with v4.14, this is exploitable by unprivileged users as long as | |
| 17 | the unprivileged_bpf_disabled sysctl isn't set. | |
| 18 | ||
| 19 | Debian assigned CVE-2017-16995 for this issue. | |
| 20 | ||
| 21 | v3: | |
| 22 | - add CVE number (Ben Hutchings) | |
| 23 | ||
| 24 | Fixes: 484611357c19 ("bpf: allow access into map value arrays") | |
| 25 | Signed-off-by: Jann Horn <jannh@google.com> | |
| 26 | Acked-by: Edward Cree <ecree@solarflare.com> | |
| 27 | Signed-off-by: Alexei Starovoitov <ast@kernel.org> | |
| 28 | Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> | |
| 29 | CVE-2017-16995 | |
| 30 | Signed-off-by: Seth Forshee <seth.forshee@canonical.com> | |
| 31 | Signed-off-by: Andy Whitcroft <apw@canonical.com> | |
| 32 | Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> | |
| 33 | (cherry picked from commit 868c88129c7567525dbde3cb6989a5acd478bd80) | |
| 34 | Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> | |
| 35 | --- | |
| 36 | kernel/bpf/verifier.c | 15 +++++++++++---- | |
| 37 | 1 file changed, 11 insertions(+), 4 deletions(-) | |
| 38 | ||
| 39 | diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c | |
| 40 | index 4321625fe32a..cdfa07a4ef27 100644 | |
| 41 | --- a/kernel/bpf/verifier.c | |
| 42 | +++ b/kernel/bpf/verifier.c | |
| 43 | @@ -2048,12 +2048,19 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) | |
| 44 | /* case: R = imm | |
| 45 | * remember the value we stored into this reg | |
| 46 | */ | |
| 47 | + u64 imm; | |
| 48 | + | |
| 49 | + if (BPF_CLASS(insn->code) == BPF_ALU64) | |
| 50 | + imm = insn->imm; | |
| 51 | + else | |
| 52 | + imm = (u32)insn->imm; | |
| 53 | + | |
| 54 | regs[insn->dst_reg].type = CONST_IMM; | |
| 55 | - regs[insn->dst_reg].imm = insn->imm; | |
| 56 | + regs[insn->dst_reg].imm = imm; | |
| 57 | regs[insn->dst_reg].id = 0; | |
| 58 | - regs[insn->dst_reg].max_value = insn->imm; | |
| 59 | - regs[insn->dst_reg].min_value = insn->imm; | |
| 60 | - regs[insn->dst_reg].min_align = calc_align(insn->imm); | |
| 61 | + regs[insn->dst_reg].max_value = imm; | |
| 62 | + regs[insn->dst_reg].min_value = imm; | |
| 63 | + regs[insn->dst_reg].min_align = calc_align(imm); | |
| 64 | regs[insn->dst_reg].value_from_signed = false; | |
| 65 | } | |
| 66 | ||
| 67 | -- | |
| 68 | 2.14.2 | |
| 69 |