From 6f9a093b66ce7cacc110d8737c03686e80ecfda6 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 18 Jun 2014 15:34:57 -0700 Subject: [PATCH] net: filter: fix upper BPF instruction limit The original checks (via sk_chk_filter) for instruction count uses ">", not ">=", so changing this in sk_convert_filter has the potential to break existing seccomp filters that used exactly BPF_MAXINSNS many instructions. Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set") Signed-off-by: Kees Cook Cc: stable@vger.kernel.org # v3.15+ Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- net/core/filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index 735fad897496..a44e12cdde4c 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -840,7 +840,7 @@ int sk_convert_filter(struct sock_filter *prog, int len, BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK); BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); - if (len <= 0 || len >= BPF_MAXINSNS) + if (len <= 0 || len > BPF_MAXINSNS) return -EINVAL; if (new_prog) { -- 2.20.1