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authorDmitry Mishin <dim@openvz.org>2006-10-30 15:12:55 -0800
committerDavid S. Miller <davem@sunset.davemloft.net>2006-10-30 15:24:44 -0800
commit590bdf7fd2292b47c428111cb1360e312eff207e (patch)
treec44b60a5e40b5e16e3478aecb839825b4a602ced /net/ipv4
parent844dc7c88046ecd2e52596730d7cc400d6c3ad67 (diff)
[NETFILTER]: Missed and reordered checks in {arp,ip,ip6}_tables
There is a number of issues in parsing user-provided table in translate_table(). Malicious user with CAP_NET_ADMIN may crash system by passing special-crafted table to the *_tables. The first issue is that mark_source_chains() function is called before entry content checks. In case of standard target, mark_source_chains() function uses t->verdict field in order to determine new position. But the check, that this field leads no further, than the table end, is in check_entry(), which is called later, than mark_source_chains(). The second issue, that there is no check that target_offset points inside entry. If so, *_ITERATE_MATCH macro will follow further, than the entry ends. As a result, we'll have oops or memory disclosure. And the third issue, that there is no check that the target is completely inside entry. Results are the same, as in previous issue. Signed-off-by: Dmitry Mishin <dim@openvz.org> Acked-by: Kirill Korotaev <dev@openvz.org> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/netfilter/arp_tables.c25
-rw-r--r--net/ipv4/netfilter/ip_tables.c30
2 files changed, 38 insertions, 17 deletions
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 0849f1cced1..413c2d0a1f3 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -466,7 +466,13 @@ static inline int check_entry(struct arpt_entry *e, const char *name, unsigned i
return -EINVAL;
}
+ if (e->target_offset + sizeof(struct arpt_entry_target) > e->next_offset)
+ return -EINVAL;
+
t = arpt_get_target(e);
+ if (e->target_offset + t->u.target_size > e->next_offset)
+ return -EINVAL;
+
target = try_then_request_module(xt_find_target(NF_ARP, t->u.user.name,
t->u.user.revision),
"arpt_%s", t->u.user.name);
@@ -621,20 +627,18 @@ 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) {
- ARPT_ENTRY_ITERATE(entry0, newinfo->size,
- cleanup_entry, &i);
- return ret;
+ if (ret != 0)
+ goto cleanup;
+
+ ret = -ELOOP;
+ if (!mark_source_chains(newinfo, valid_hooks, entry0)) {
+ duprintf("Looping hook\n");
+ goto cleanup;
}
/* And one copy for every other CPU */
@@ -643,6 +647,9 @@ 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;
}
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 4b90927619b..e2c7f6e024c 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -547,12 +547,18 @@ check_entry(struct ipt_entry *e, const char *name, unsigned int size,
return -EINVAL;
}
+ if (e->target_offset + sizeof(struct ipt_entry_target) > e->next_offset)
+ return -EINVAL;
+
j = 0;
ret = IPT_MATCH_ITERATE(e, check_match, name, &e->ip, e->comefrom, &j);
if (ret != 0)
goto cleanup_matches;
t = ipt_get_target(e);
+ ret = -EINVAL;
+ if (e->target_offset + t->u.target_size > e->next_offset)
+ goto cleanup_matches;
target = try_then_request_module(xt_find_target(AF_INET,
t->u.user.name,
t->u.user.revision),
@@ -712,19 +718,17 @@ translate_table(const char *name,
}
}
- if (!mark_source_chains(newinfo, valid_hooks, entry0))
- return -ELOOP;
-
/* Finally, each sanity check must pass */
i = 0;
ret = IPT_ENTRY_ITERATE(entry0, newinfo->size,
check_entry, name, size, &i);
- if (ret != 0) {
- IPT_ENTRY_ITERATE(entry0, newinfo->size,
- cleanup_entry, &i);
- return ret;
- }
+ if (ret != 0)
+ goto cleanup;
+
+ ret = -ELOOP;
+ if (!mark_source_chains(newinfo, valid_hooks, entry0))
+ goto cleanup;
/* And one copy for every other CPU */
for_each_possible_cpu(i) {
@@ -732,6 +736,9 @@ translate_table(const char *name,
memcpy(newinfo->entries[i], entry0, newinfo->size);
}
+ return 0;
+cleanup:
+ IPT_ENTRY_ITERATE(entry0, newinfo->size, cleanup_entry, &i);
return ret;
}
@@ -1463,6 +1470,10 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
return -EINVAL;
}
+ if (e->target_offset + sizeof(struct compat_xt_entry_target) >
+ e->next_offset)
+ return -EINVAL;
+
off = 0;
entry_offset = (void *)e - (void *)base;
j = 0;
@@ -1472,6 +1483,9 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
goto cleanup_matches;
t = ipt_get_target(e);
+ ret = -EINVAL;
+ if (e->target_offset + t->u.target_size > e->next_offset)
+ goto cleanup_matches;
target = try_then_request_module(xt_find_target(AF_INET,
t->u.user.name,
t->u.user.revision),