| Message ID | 1437065195-10887-2-git-send-email-nschichan@freebox.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index 4550d24..21f5ace 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;
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 <nschichan@freebox.fr> --- arch/arm/net/bpf_jit_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)