netfilter: x_tables: add compat version of xt_check_entry_offsets
commit fc1221b3a163d1386d1052184202d5dc50d302d1 upstream.
32bit rulesets have different layout and alignment requirements, so once
more integrity checks get added to xt_check_entry_offsets it will reject
well-formed 32bit rulesets.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 1d2657f..e3a3d05 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -492,6 +492,9 @@
unsigned int *size);
int xt_compat_target_to_user(const struct xt_entry_target *t,
void __user **dstptr, unsigned int *size);
+int xt_compat_check_entry_offsets(const void *base,
+ unsigned int target_offset,
+ unsigned int next_offset);
#endif /* CONFIG_COMPAT */
#endif /* _X_TABLES_H */
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index ae7344f..b05405f 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -1253,7 +1253,8 @@
if (!arp_checkentry(&e->arp))
return -EINVAL;
- ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset);
+ ret = xt_compat_check_entry_offsets(e, e->target_offset,
+ e->next_offset);
if (ret)
return ret;
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index ddff8f7..b83a336 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1512,7 +1512,8 @@
if (!ip_checkentry(&e->ip))
return -EINVAL;
- ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset);
+ ret = xt_compat_check_entry_offsets(e,
+ e->target_offset, e->next_offset);
if (ret)
return ret;
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index d6e3c01..d803519 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1524,7 +1524,8 @@
if (!ip6_checkentry(&e->ipv6))
return -EINVAL;
- ret = xt_check_entry_offsets(e, e->target_offset, e->next_offset);
+ ret = xt_compat_check_entry_offsets(e,
+ e->target_offset, e->next_offset);
if (ret)
return ret;
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index e3e2dd4..cfdb959 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -538,6 +538,27 @@
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
+
+int xt_compat_check_entry_offsets(const void *base,
+ unsigned int target_offset,
+ unsigned int next_offset)
+{
+ const struct compat_xt_entry_target *t;
+ const char *e = base;
+
+ if (target_offset + sizeof(*t) > next_offset)
+ return -EINVAL;
+
+ t = (void *)(e + target_offset);
+ if (t->u.target_size < sizeof(*t))
+ return -EINVAL;
+
+ if (target_offset + t->u.target_size > next_offset)
+ return -EINVAL;
+
+ return 0;
+}
+EXPORT_SYMBOL(xt_compat_check_entry_offsets);
#endif /* CONFIG_COMPAT */
/**
@@ -548,6 +569,7 @@
* @next_offset: the arp/ip/ip6_t->next_offset
*
* validates that target_offset and next_offset are sane.
+ * Also see xt_compat_check_entry_offsets for CONFIG_COMPAT version.
*
* The arp/ip/ip6t_entry structure @base must have passed following tests:
* - it must point to a valid memory location
