From 0d3d077cd4f1154e63a9858e47fe3fb1ad0c03e5 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 24 Apr 2005 20:16:19 -0700 Subject: [PATCH] [SELINUX]: Fix ipv6_skip_exthdr() invocation causing OOPS. The SELinux hooks invoke ipv6_skip_exthdr() with an incorrect length final argument. However, the length argument turns out to be superfluous. I was just reading ipv6_skip_exthdr and it occured to me that we can get rid of len altogether. The only place where len is used is to check whether the skb has two bytes for ipv6_opt_hdr. This check is done by skb_header_pointer/skb_copy_bits anyway. Now it might appear that we've made the code slower by deferring the check to skb_copy_bits. However, this check should not trigger in the common case so this is OK. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/net/ipv6.h | 2 +- net/ipv6/exthdrs_core.c | 11 ++++------- net/ipv6/icmp.c | 4 ++-- security/selinux/hooks.c | 3 +-- 4 files changed, 8 insertions(+), 12 deletions(-) diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 87c45cbfbaf6..771b47e30f86 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -416,7 +416,7 @@ extern void ipv6_push_frag_opts(struct sk_buff *skb, u8 *proto); extern int ipv6_skip_exthdr(const struct sk_buff *, int start, - u8 *nexthdrp, int len); + u8 *nexthdrp); extern int ipv6_ext_hdr(u8 nexthdr); diff --git a/net/ipv6/exthdrs_core.c b/net/ipv6/exthdrs_core.c index 6dda815c013f..315bc1fbec3f 100644 --- a/net/ipv6/exthdrs_core.c +++ b/net/ipv6/exthdrs_core.c @@ -41,8 +41,8 @@ int ipv6_ext_hdr(u8 nexthdr) * when Linux implements ESP (and maybe AUTH) headers. * --AK * - * This function parses (probably truncated) exthdr set "hdr" - * of length "len". "nexthdrp" initially points to some place, + * This function parses (probably truncated) exthdr set "hdr". + * "nexthdrp" initially points to some place, * where type of the first header can be found. * * It skips all well-known exthdrs, and returns pointer to the start @@ -63,7 +63,7 @@ int ipv6_ext_hdr(u8 nexthdr) * --ANK (980726) */ -int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp, int len) +int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp) { u8 nexthdr = *nexthdrp; @@ -71,13 +71,11 @@ int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp, int len struct ipv6_opt_hdr _hdr, *hp; int hdrlen; - if (len < (int)sizeof(struct ipv6_opt_hdr)) - return -1; if (nexthdr == NEXTHDR_NONE) return -1; hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr); if (hp == NULL) - BUG(); + return -1; if (nexthdr == NEXTHDR_FRAGMENT) { unsigned short _frag_off, *fp; fp = skb_header_pointer(skb, @@ -97,7 +95,6 @@ int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp, int len hdrlen = ipv6_optlen(hp); nexthdr = hp->nexthdr; - len -= hdrlen; start += hdrlen; } diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 87b9082ceab2..8e0f569b883e 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -135,7 +135,7 @@ static int is_ineligible(struct sk_buff *skb) if (len < 0) return 1; - ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, len); + ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr); if (ptr < 0) return 0; if (nexthdr == IPPROTO_ICMPV6) { @@ -514,7 +514,7 @@ static void icmpv6_notify(struct sk_buff *skb, int type, int code, u32 info) nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; if (ipv6_ext_hdr(nexthdr)) { /* now skip over extension headers */ - inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, skb->len - sizeof(struct ipv6hdr)); + inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr); if (inner_offset<0) return; } else { diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 2ae7d3cb8df4..0d378141c95a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2855,8 +2855,7 @@ static int selinux_parse_skb_ipv6(struct sk_buff *skb, struct avc_audit_data *ad nexthdr = ip6->nexthdr; offset += sizeof(_ipv6h); - offset = ipv6_skip_exthdr(skb, offset, &nexthdr, - skb->tail - skb->head - offset); + offset = ipv6_skip_exthdr(skb, offset, &nexthdr); if (offset < 0) goto out; -- 2.30.2