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| author | Xi Wang <xi.wang@gmail.com> | 2015-05-08 06:39:51 +0100 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-06-10 13:42:27 -0400 |
| commit | a45b402bb2ec47fcb140d86098f035382680a31d (patch) | |
| tree | c380bd28916ee3c794331a7847c8233fe4f9ebfd /arch/arm64 | |
| parent | 748e016cf59aef21d02d1ba7ff2a337d616c83c7 (diff) | |
| download | lwn-a45b402bb2ec47fcb140d86098f035382680a31d.tar.gz lwn-a45b402bb2ec47fcb140d86098f035382680a31d.zip | |
arm64: bpf: fix signedness bug in loading 64-bit immediate
[ Upstream commit 1e4df6b7208140f3c49f316d33a409d3a161f350 ]
Consider "(u64)insn1.imm << 32 | imm" in the arm64 JIT. Since imm is
signed 32-bit, it is sign-extended to 64-bit, losing the high 32 bits.
The fix is to convert imm to u32 first, which will be zero-extended to
u64 implicitly.
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 30d3d94cc3d5 ("arm64: bpf: add 'load 64-bit immediate' instruction")
Signed-off-by: Xi Wang <xi.wang@gmail.com>
[will: removed non-arm64 bits and redundant casting]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index edba042b2325..dc6a4842683a 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -487,7 +487,7 @@ emit_cond_jmp: return -EINVAL; } - imm64 = (u64)insn1.imm << 32 | imm; + imm64 = (u64)insn1.imm << 32 | (u32)imm; emit_a64_mov_i64(dst, imm64, ctx); return 1; |