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Commit 3e8fe7dd authored by Yasuyuki Kozakai's avatar Yasuyuki Kozakai Committed by David S. Miller
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[NETFILTER]: Fix multiple bugs in ip6t_frag.c 

The first patch fixes following bugs in ip6t_frag.c,

- Wrong cast the pointer to extension header.
- header length of Fragment Header is statically 8 octets.
  Then the option --frag-len doesn't make sense.
- There are endian issues where using frag->info.
- Reserved fields are not 2 bit but 8bit + 2 bit. (see RFC2460)
Signed-off-by: default avatarYasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5b8403d6
Hide whitespace changes
Inline Side-by-side
Showing with 37 additions and 59 deletions
net/ipv6/netfilter/ip6t_frag.c
View file @ 3e8fe7dd
......@@ -14,8 +14,6 @@
#include <net/checksum.h>
#include <net/ipv6.h>
#include <asm/byteorder.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter_ipv6/ip6t_frag.h>
......@@ -29,29 +27,6 @@ MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
#define DEBUGP(format, args...)
#endif
#if 0
#if BYTE_ORDER == BIG_ENDIAN
#define IP6F_OFF_MASK 0xfff8 /* mask out offset from _offlg */
#define IP6F_RESERVED_MASK 0x0006 /* reserved bits in ip6f_offlg */
#define IP6F_MORE_FRAG 0x0001 /* more-fragments flag */
#else /* BYTE_ORDER == LITTLE_ENDIAN */
#define IP6F_OFF_MASK 0xf8ff /* mask out offset from _offlg */
#define IP6F_RESERVED_MASK 0x0600 /* reserved bits in ip6f_offlg */
#define IP6F_MORE_FRAG 0x0100 /* more-fragments flag */
#endif
#endif
#define IP6F_OFF_MASK 0xf8ff /* mask out offset from _offlg */
#define IP6F_RESERVED_MASK 0x0600 /* reserved bits in ip6f_offlg */
#define IP6F_MORE_FRAG 0x0100 /* more-fragments flag */
struct fraghdr {
__u8 nexthdr;
__u8 hdrlen;
__u16 info;
__u32 id;
};
/* Returns 1 if the id is matched by the range, 0 otherwise */
static inline int
id_match(u_int32_t min, u_int32_t max, u_int32_t id, int invert)
......@@ -74,7 +49,7 @@ match(const struct sk_buff *skb,
u_int16_t datalen,
int *hotdrop)
{
struct fraghdr *frag = NULL;
struct frag_hdr *frag = NULL;
const struct ip6t_frag *fraginfo = matchinfo;
unsigned int temp;
int len;
......@@ -107,7 +82,7 @@ match(const struct sk_buff *skb,
break;
}
hdr=(struct ipv6_opt_hdr *)skb->data+ptr;
hdr=(struct ipv6_opt_hdr *)(skb->data+ptr);
/* Calculate the header length */
if (nexthdr == NEXTHDR_FRAGMENT) {
......@@ -150,59 +125,62 @@ match(const struct sk_buff *skb,
/* FRAG header not found */
if ( temp != MASK_FRAGMENT ) return 0;
if (len < (int)sizeof(struct fraghdr)){
if (len < sizeof(struct frag_hdr)){
*hotdrop = 1;
return 0;
}
frag = (struct fraghdr *) (skb->data + ptr);
frag = (struct frag_hdr *) (skb->data + ptr);
DEBUGP("IPv6 FRAG LEN %u %u ", hdrlen, frag->hdrlen);
DEBUGP("INFO %04X ", frag->info);
DEBUGP("OFFSET %04X ", frag->info & IP6F_OFF_MASK);
DEBUGP("RES %04X ", frag->info & IP6F_RESERVED_MASK);
DEBUGP("MF %04X ", frag->info & IP6F_MORE_FRAG);
DEBUGP("ID %u %08X\n", ntohl(frag->id), ntohl(frag->id));
DEBUGP("INFO %04X ", frag->frag_off);
DEBUGP("OFFSET %04X ", ntohs(frag->frag_off) & ~0x7);
DEBUGP("RES %02X %04X", frag->reserved, ntohs(frag->frag_off) & 0x6);
DEBUGP("MF %04X ", frag->frag_off & htons(IP6_MF));
DEBUGP("ID %u %08X\n", ntohl(frag->identification),
ntohl(frag->identification));
DEBUGP("IPv6 FRAG id %02X ",
(id_match(fraginfo->ids[0], fraginfo->ids[1],
ntohl(frag->id),
ntohl(frag->identification),
!!(fraginfo->invflags & IP6T_FRAG_INV_IDS))));
DEBUGP("len %02X %04X %02X ",
fraginfo->hdrlen, hdrlen,
(!fraginfo->hdrlen ||
(fraginfo->hdrlen == hdrlen) ^
!!(fraginfo->invflags & IP6T_FRAG_INV_LEN)));
DEBUGP("res %02X %02X %02X ",
(fraginfo->flags & IP6T_FRAG_RES), frag->info & IP6F_RESERVED_MASK,
!((fraginfo->flags & IP6T_FRAG_RES) && (frag->info & IP6F_RESERVED_MASK)));
DEBUGP("res %02X %02X%04X %02X ",
(fraginfo->flags & IP6T_FRAG_RES), frag->reserved,
ntohs(frag->frag_off) & 0x6,
!((fraginfo->flags & IP6T_FRAG_RES)
&& (frag->reserved || (ntohs(frag->frag_off) & 0x6))));
DEBUGP("first %02X %02X %02X ",
(fraginfo->flags & IP6T_FRAG_FST), frag->info & IP6F_OFF_MASK,
!((fraginfo->flags & IP6T_FRAG_FST) && (frag->info & IP6F_OFF_MASK)));
(fraginfo->flags & IP6T_FRAG_FST),
ntohs(frag->frag_off) & ~0x7,
!((fraginfo->flags & IP6T_FRAG_FST)
&& (ntohs(frag->frag_off) & ~0x7)));
DEBUGP("mf %02X %02X %02X ",
(fraginfo->flags & IP6T_FRAG_MF), frag->info & IP6F_MORE_FRAG,
!((fraginfo->flags & IP6T_FRAG_MF) && !((frag->info & IP6F_MORE_FRAG))));
(fraginfo->flags & IP6T_FRAG_MF),
ntohs(frag->frag_off) & IP6_MF,
!((fraginfo->flags & IP6T_FRAG_MF)
&& !((ntohs(frag->frag_off) & IP6_MF))));
DEBUGP("last %02X %02X %02X\n",
(fraginfo->flags & IP6T_FRAG_NMF), frag->info & IP6F_MORE_FRAG,
!((fraginfo->flags & IP6T_FRAG_NMF) && (frag->info & IP6F_MORE_FRAG)));
(fraginfo->flags & IP6T_FRAG_NMF),
ntohs(frag->frag_off) & IP6_MF,
!((fraginfo->flags & IP6T_FRAG_NMF)
&& (ntohs(frag->frag_off) & IP6_MF)));
return (frag != NULL)
&&
(id_match(fraginfo->ids[0], fraginfo->ids[1],
ntohl(frag->id),
ntohl(frag->identification),
!!(fraginfo->invflags & IP6T_FRAG_INV_IDS)))
&&
(!fraginfo->hdrlen ||
(fraginfo->hdrlen == hdrlen) ^
!!(fraginfo->invflags & IP6T_FRAG_INV_LEN))
&&
!((fraginfo->flags & IP6T_FRAG_RES) && (frag->info & IP6F_RESERVED_MASK))
!((fraginfo->flags & IP6T_FRAG_RES)
&& (frag->reserved || (ntohs(frag->frag_off) & 0x6)))
&&
!((fraginfo->flags & IP6T_FRAG_FST) && (frag->info & IP6F_OFF_MASK))
!((fraginfo->flags & IP6T_FRAG_FST)
&& (ntohs(frag->frag_off) & ~0x7))
&&
!((fraginfo->flags & IP6T_FRAG_MF) && !((frag->info & IP6F_MORE_FRAG)))
!((fraginfo->flags & IP6T_FRAG_MF)
&& !(ntohs(frag->frag_off) & IP6_MF))
&&
!((fraginfo->flags & IP6T_FRAG_NMF) && (frag->info & IP6F_MORE_FRAG));
!((fraginfo->flags & IP6T_FRAG_NMF)
&& (ntohs(frag->frag_off) & IP6_MF));
}
/* Called when user tries to insert an entry of this type. */
......
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