[NETFILTER]: Fix {ip,ip6,arp}_tables hook validation

Commit 590bdf7fd2292b47c428111cb1360e312eff207e introduced a regression
in match/target hook validation. mark_source_chains builds a bitmask
for each rule representing the hooks it can be reached from, which is
then used by the matches and targets to make sure they are only called
from valid hooks. The patch moved the match/target specific validation
before the mark_source_chains call, at which point the mask is always zero.

This patch returns back to the old order and moves the standard checks
to mark_source_chains. This allows to get rid of a special case for
standard targets as a nice side-effect.

Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 24 deletions

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 413c2d0a1f3..71b76ade00e 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -375,6 +375,13 @@ static int mark_source_chains(struct xt_table_info *newinfo,
 			    && unconditional(&e->arp)) {
 				unsigned int oldpos, size;
 
+				if (t->verdict < -NF_MAX_VERDICT - 1) {
+					duprintf("mark_source_chains: bad "
+						"negative verdict (%i)\n",
+								t->verdict);
+					return 0;
+				}
+
 				/* Return: backtrack through the last
 				 * big jump.
 				 */
@@ -404,6 +411,14 @@ static int mark_source_chains(struct xt_table_info *newinfo,
 				if (strcmp(t->target.u.user.name,
 					   ARPT_STANDARD_TARGET) == 0
 				    && newpos >= 0) {
+					if (newpos > newinfo->size -
+						sizeof(struct arpt_entry)) {
+						duprintf("mark_source_chains: "
+							"bad verdict (%i)\n",
+								newpos);
+						return 0;
+					}
+
 					/* This a jump; chase it. */
 					duprintf("Jump rule %u -> %u\n",
 						 pos, newpos);
@@ -426,8 +441,6 @@ static int mark_source_chains(struct xt_table_info *newinfo,
 static inline int standard_check(const struct arpt_entry_target *t,
 				 unsigned int max_offset)
 {
-	struct arpt_standard_target *targ = (void *)t;
-
 	/* Check standard info. */
 	if (t->u.target_size
 	    != ARPT_ALIGN(sizeof(struct arpt_standard_target))) {
@@ -437,18 +450,6 @@ static inline int standard_check(const struct arpt_entry_target *t,
 		return 0;
 	}
 
-	if (targ->verdict >= 0
-	    && targ->verdict > max_offset - sizeof(struct arpt_entry)) {
-		duprintf("arpt_standard_check: bad verdict (%i)\n",
-			 targ->verdict);
-		return 0;
-	}
-
-	if (targ->verdict < -NF_MAX_VERDICT - 1) {
-		duprintf("arpt_standard_check: bad negative verdict (%i)\n",
-			 targ->verdict);
-		return 0;
-	}
 	return 1;
 }
 
@@ -627,18 +628,20 @@ static int translate_table(const char *name,
 		}
 	}
 
+	if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
+		duprintf("Looping hook\n");
+		return -ELOOP;
+	}
+
 	/* Finally, each sanity check must pass */
 	i = 0;
 	ret = ARPT_ENTRY_ITERATE(entry0, newinfo->size,
 				 check_entry, name, size, &i);
 
-	if (ret != 0)
-		goto cleanup;
-
-	ret = -ELOOP;
-	if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
-		duprintf("Looping hook\n");
-		goto cleanup;
+	if (ret != 0) {
+		ARPT_ENTRY_ITERATE(entry0, newinfo->size,
+				cleanup_entry, &i);
+		return ret;
 	}
 
 	/* And one copy for every other CPU */
@@ -647,9 +650,6 @@ static int translate_table(const char *name,
 			memcpy(newinfo->entries[i], entry0, newinfo->size);
 	}
 
-	return 0;
-cleanup:
-	ARPT_ENTRY_ITERATE(entry0, newinfo->size, cleanup_entry, &i);
 	return ret;
 }