Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1319679
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.3 133/157] arm64: bpf: fix div-by-zero case |
| Date | 2016-01-27 21:30 +0100 |
| Message-ID | <qVET1-FR-31@gated-at.bofh.it> (permalink) |
| References | <qVCRc-7CM-17@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.3-stable review patch. If anyone has any objections, please let me know.
------------------
From: Zi Shen Lim <zlim.lnx@gmail.com>
commit 251599e1d6906621f49218d7b474ddd159e58f3b upstream.
In the case of division by zero in a BPF program:
A = A / X; (X == 0)
the expected behavior is to terminate with return value 0.
This is confirmed by the test case introduced in commit 86bf1721b226
("test_bpf: add tests checking that JIT/interpreter sets A and X to 0.").
Reported-by: Yang Shi <yang.shi@linaro.org>
Tested-by: Yang Shi <yang.shi@linaro.org>
CC: Xi Wang <xi.wang@gmail.com>
CC: Alexei Starovoitov <ast@plumgrid.com>
CC: linux-arm-kernel@lists.infradead.org
CC: linux-kernel@vger.kernel.org
Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler")
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/net/bpf_jit.h | 3 ++-
arch/arm64/net/bpf_jit_comp.c | 37 +++++++++++++++++++++++++------------
2 files changed, 27 insertions(+), 13 deletions(-)
--- a/arch/arm64/net/bpf_jit.h
+++ b/arch/arm64/net/bpf_jit.h
@@ -1,7 +1,7 @@
/*
* BPF JIT compiler for ARM64
*
- * Copyright (C) 2014 Zi Shen Lim <zlim.lnx@gmail.com>
+ * Copyright (C) 2014-2015 Zi Shen Lim <zlim.lnx@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -35,6 +35,7 @@
aarch64_insn_gen_comp_branch_imm(0, offset, Rt, A64_VARIANT(sf), \
AARCH64_INSN_BRANCH_COMP_##type)
#define A64_CBZ(sf, Rt, imm19) A64_COMP_BRANCH(sf, Rt, (imm19) << 2, ZERO)
+#define A64_CBNZ(sf, Rt, imm19) A64_COMP_BRANCH(sf, Rt, (imm19) << 2, NONZERO)
/* Conditional branch (immediate) */
#define A64_COND_BRANCH(cond, offset) \
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1,7 +1,7 @@
/*
* BPF JIT compiler for ARM64
*
- * Copyright (C) 2014 Zi Shen Lim <zlim.lnx@gmail.com>
+ * Copyright (C) 2014-2015 Zi Shen Lim <zlim.lnx@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -225,6 +225,17 @@ static int build_insn(const struct bpf_i
u8 jmp_cond;
s32 jmp_offset;
+#define check_imm(bits, imm) do { \
+ if ((((imm) > 0) && ((imm) >> (bits))) || \
+ (((imm) < 0) && (~(imm) >> (bits)))) { \
+ pr_info("[%2d] imm=%d(0x%x) out of range\n", \
+ i, imm, imm); \
+ return -EINVAL; \
+ } \
+} while (0)
+#define check_imm19(imm) check_imm(19, imm)
+#define check_imm26(imm) check_imm(26, imm)
+
switch (code) {
/* dst = src */
case BPF_ALU | BPF_MOV | BPF_X:
@@ -258,8 +269,21 @@ static int build_insn(const struct bpf_i
break;
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_X:
+ {
+ const u8 r0 = bpf2a64[BPF_REG_0];
+
+ /* if (src == 0) return 0 */
+ jmp_offset = 3; /* skip ahead to else path */
+ check_imm19(jmp_offset);
+ emit(A64_CBNZ(is64, src, jmp_offset), ctx);
+ emit(A64_MOVZ(1, r0, 0, 0), ctx);
+ jmp_offset = epilogue_offset(ctx);
+ check_imm26(jmp_offset);
+ emit(A64_B(jmp_offset), ctx);
+ /* else */
emit(A64_UDIV(is64, dst, dst, src), ctx);
break;
+ }
case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_X:
ctx->tmp_used = 1;
@@ -393,17 +417,6 @@ emit_bswap_uxt:
emit(A64_ASR(is64, dst, dst, imm), ctx);
break;
-#define check_imm(bits, imm) do { \
- if ((((imm) > 0) && ((imm) >> (bits))) || \
- (((imm) < 0) && (~(imm) >> (bits)))) { \
- pr_info("[%2d] imm=%d(0x%x) out of range\n", \
- i, imm, imm); \
- return -EINVAL; \
- } \
-} while (0)
-#define check_imm19(imm) check_imm(19, imm)
-#define check_imm26(imm) check_imm(26, imm)
-
/* JUMP off */
case BPF_JMP | BPF_JA:
jmp_offset = bpf2a64_offset(i + off, i, ctx);
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 4.3 000/157] 4.3.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 20:10 +0100
[PATCH 4.3 001/157] x86 smpboot: Re-enable init_udelay=0 by default on modern CPUs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 20:10 +0100
Re: [PATCH 4.3 001/157] x86 smpboot: Re-enable init_udelay=0 by default on modern CPUs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 23:30 +0100
Re: [PATCH 4.3 001/157] x86 smpboot: Re-enable init_udelay=0 by default on modern CPUs Donald Parsons <dparsons@brightdsl.net> - 2016-01-27 23:30 +0100
[PATCH 4.3 052/157] ALSA: seq: Fix race at timer setup and close Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 20:10 +0100
[PATCH 4.3 046/157] ALSA: hda - Add mic mute hotkey quirk for Lenovo ThinkCentre AIO Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 20:10 +0100
[PATCH 4.3 010/157] KVM: svm: unconditionally intercept #DB Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 20:10 +0100
[PATCH 4.3 155/157] mn10300: Select CONFIG_HAVE_UID16 to fix build failure Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 20:10 +0100
[PATCH 4.3 154/157] fix the regression from "direct-io: Fix negative return from dio read beyond eof" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:20 +0100
[PATCH 4.3 126/157] powerpc/opal-irqchip: Fix deadlock introduced by "Fix double endian conversion" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:20 +0100
[PATCH 4.3 135/157] arm64: cmpxchg_dbl: fix return value type Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:20 +0100
[PATCH 4.3 134/157] arm64: bpf: fix mod-by-zero case Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:20 +0100
[PATCH 4.3 044/157] ALSA: hda - Set SKL+ hda controller power at freeze() and thaw() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 128/157] powerpc: Make value-returning atomics fully ordered Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 157/157] arm64: KVM: Add workaround for Cortex-A57 erratum 834220 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 131/157] powerpc/module: Handle R_PPC64_ENTRY relocations Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 129/157] powerpc: Make {cmp}xchg* and their atomic_ versions fully ordered Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 133/157] arm64: bpf: fix div-by-zero case Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 156/157] arm64: restore bogomips information in /proc/cpuinfo Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 147/157] parisc iommu: fix panic due to trying to allocate too large region Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 132/157] recordmcount: arm64: Replace the ignored mcount call into nop Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 148/157] HID: wacom: Tie cached HID_DG_CONTACTCOUNT indices to report ID Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 150/157] HID: core: Avoid uninitialized buffer access Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 149/157] HID: wacom: Expect touch_max touches if HID_DG_CONTACTCOUNT not present Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 130/157] scripts/recordmcount.pl: support data in text section on powerpc Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
[PATCH 4.3 153/157] direct-io: Fix negative return from dio read beyond eof Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-01-27 21:30 +0100
Re: [PATCH 4.3 000/157] 4.3.5-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-01-28 00:30 +0100
Re: [PATCH 4.3 000/157] 4.3.5-stable review Guenter Roeck <linux@roeck-us.net> - 2016-01-28 03:20 +0100
csiph-web