netdev - [PATCH bpf-next 12/13] bpf, arm: remove obsolete exception handling from div/mod

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180126223348.11250-13-daniel@iogearbox.net>
Date:   Fri, 26 Jan 2018 23:33:47 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     ast@...nel.org
Cc:     netdev@...r.kernel.org, Daniel Borkmann <daniel@...earbox.net>,
        Shubham Bansal <illusionist.neo@...il.com>
Subject: [PATCH bpf-next 12/13] bpf, arm: remove obsolete exception handling from div/mod

Since we've changed div/mod exception handling for src_reg in
eBPF verifier itself, remove the leftovers from arm32 JIT.

Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
Cc: Shubham Bansal <illusionist.neo@...il.com>
---
 arch/arm/net/bpf_jit_32.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 41e2feb..b5030e1 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -363,15 +363,7 @@ static inline int epilogue_offset(const struct jit_ctx *ctx)
 static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, u8 op)
 {
 	const u8 *tmp = bpf2a32[TMP_REG_1];
-	s32 jmp_offset;
 
-	/* checks if divisor is zero or not. If it is, then
-	 * exit directly.
-	 */
-	emit(ARM_CMP_I(rn, 0), ctx);
-	_emit(ARM_COND_EQ, ARM_MOV_I(ARM_R0, 0), ctx);
-	jmp_offset = epilogue_offset(ctx);
-	_emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
 #if __LINUX_ARM_ARCH__ == 7
 	if (elf_hwcap & HWCAP_IDIVA) {
 		if (op == BPF_DIV)
-- 
2.9.5