: Fix multiple bugs in ip6t_frag.c

This patch fixes another invalid cast and endian issues when using frag_off in ip6t_frag. It also removes some dead code and a useless check.

# This is a BitKeeper generated diff -Nru style patch. #
# ChangeSet
# 2004/10/14 01:06:10+02:00 [email protected]
# [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: Yasuyuki KOZAKAI <[email protected]>
# Signed-off-by: Patrick McHardy <[email protected]>
#

# net/ipv6/netfilter/ip6t_frag.c
#   2004/10/14 01:05:45+02:00 [email protected] +37 -59
#   [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: Yasuyuki KOZAKAI <[email protected]>
#   Signed-off-by: Patrick McHardy <[email protected]>
# 
diff -Nru a/net/ipv6/netfilter/ip6t_frag.c b/net/ipv6/netfilter/ip6t_frag.c
--- a/net/ipv6/netfilter/ip6t_frag.c	2004-10-14 01:37:39 +02:00
+++ b/net/ipv6/netfilter/ip6t_frag.c	2004-10-14 01:37:39 +02:00
@@ -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 @@
#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 @@

       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 @@
                      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 @@
        /* 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. */