| From 1e4df6b7208140f3c49f316d33a409d3a161f350 Mon Sep 17 00:00:00 2001 |
| From: Xi Wang <xi.wang@gmail.com> |
| Date: Fri, 8 May 2015 06:39:51 +0100 |
| Subject: arm64: bpf: fix signedness bug in loading 64-bit immediate |
| |
| From: Xi Wang <xi.wang@gmail.com> |
| |
| commit 1e4df6b7208140f3c49f316d33a409d3a161f350 upstream. |
| |
| 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> |
| 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/arm64/net/bpf_jit_comp.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- 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; |