Messages in this thread Patch in this message | | | Date | Fri, 11 May 2018 11:06:34 +0800 | From | Wang YanQing <> | Subject | [PATCH v2] bpf, arm32: Correct check_imm24 |
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imm24 is signed, so the right range is: [-(1<<(24 - 1)), (1<<(24 - 1)) - 1]
Note:this patch also fix a typo.
Signed-off-by: Wang YanQing <udknight@gmail.com> --- Changes v1-v2: 1:Rewrite the patch, I make a mistake, the v1 is wrong totally, reported by Russell King.
I use the fix suggested by Russell King instead of myself which use the exact number range [-8388608, 8388607]. 2:Fix the error in changelog.
Thanks!
arch/arm/net/bpf_jit_32.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index caccc78..316bc08 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -84,7 +84,7 @@ * * 1. First argument is passed using the arm 32bit registers and rest of the * arguments are passed on stack scratch space. - * 2. First callee-saved arugument is mapped to arm 32 bit registers and rest + * 2. First callee-saved argument is mapped to arm 32 bit registers and rest * arguments are mapped to scratch space on stack. * 3. We need two 64 bit temp registers to do complex operations on eBPF * registers. @@ -1199,8 +1199,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) s32 jmp_offset; #define check_imm(bits, imm) do { \ - if ((((imm) > 0) && ((imm) >> (bits))) || \ - (((imm) < 0) && (~(imm) >> (bits)))) { \ + if ((imm) >= (1 << ((bits) - 1)) || \ + (imm) < -(1 << ((bits) - 1))) { \ pr_info("[%2d] imm=%d(0x%x) out of range\n", \ i, imm, imm); \ return -EINVAL; \ -- 1.8.5.6.2.g3d8a54e.dirty
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