From 38a9cd6ec369eeeb0eff6fbce77973701a6e6a65 Mon Sep 17 00:00:00 2001 From: Nicolas Schichan Date: Tue, 21 Jul 2015 14:14:12 +0200 Subject: [PATCH] ARM: net: fix condition for load_order > 0 when translating load instructions. To check whether the load should take the fast path or not, the code would check that (r_skb_hlen - load_order) is greater than the offset of the access using an "Unsigned higher or same" condition. For halfword accesses and an skb length of 1 at offset 0, that test is valid, as we end up comparing 0xffffffff(-1) and 0, so the fast path is taken and the filter allows the load to wrongly succeed. A similar issue exists for word loads at offset 0 and an skb length of less than 4. Fix that by using the condition "Signed greater than or equal" condition for the fast path code for load orders greater than 0. Signed-off-by: Nicolas Schichan Signed-off-by: David S. Miller --- arch/arm/net/bpf_jit_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index 4550d247e308b..21f5ace156fd4 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -547,7 +547,7 @@ load_common: emit(ARM_SUB_I(r_scratch, r_skb_hl, 1 << load_order), ctx); emit(ARM_CMP_R(r_scratch, r_off), ctx); - condt = ARM_COND_HS; + condt = ARM_COND_GE; } else { emit(ARM_CMP_R(r_skb_hl, r_off), ctx); condt = ARM_COND_HI; -- 2.39.5