netfilter: nf_tables: remove WARN and add NLA_STRING upper limits

commit 9332d27d79 upstream.

This WARN can trigger because some of the names fed to the module
autoload function can be of arbitrary length.

Remove the WARN and add limits for all NLA_STRING attributes.

Reported-by: syzbot+0e63ae76d117ae1c3a01@syzkaller.appspotmail.com
Fixes: 452238e8d5 ("netfilter: nf_tables: add and use helper for module autoload")
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>
This commit is contained in:
Florian Westphal 2020-01-16 09:06:50 +01:00 committed by Greg Kroah-Hartman
parent 9da572424b
commit ba8d5b1938

View file

@ -22,6 +22,8 @@
#include <net/net_namespace.h>
#include <net/sock.h>
#define NFT_MODULE_AUTOLOAD_LIMIT (MODULE_NAME_LEN - sizeof("nft-expr-255-"))
static LIST_HEAD(nf_tables_expressions);
static LIST_HEAD(nf_tables_objects);
static LIST_HEAD(nf_tables_flowtables);
@ -521,7 +523,7 @@ static void nft_request_module(struct net *net, const char *fmt, ...)
va_start(args, fmt);
ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);
va_end(args);
if (WARN(ret >= MODULE_NAME_LEN, "truncated: '%s' (len %d)", module_name, ret))
if (ret >= MODULE_NAME_LEN)
return;
mutex_unlock(&net->nft.commit_mutex);
@ -1174,7 +1176,8 @@ static const struct nla_policy nft_chain_policy[NFTA_CHAIN_MAX + 1] = {
.len = NFT_CHAIN_MAXNAMELEN - 1 },
[NFTA_CHAIN_HOOK] = { .type = NLA_NESTED },
[NFTA_CHAIN_POLICY] = { .type = NLA_U32 },
[NFTA_CHAIN_TYPE] = { .type = NLA_STRING },
[NFTA_CHAIN_TYPE] = { .type = NLA_STRING,
.len = NFT_MODULE_AUTOLOAD_LIMIT },
[NFTA_CHAIN_COUNTERS] = { .type = NLA_NESTED },
[NFTA_CHAIN_FLAGS] = { .type = NLA_U32 },
};
@ -2088,7 +2091,8 @@ static const struct nft_expr_type *nft_expr_type_get(struct net *net,
}
static const struct nla_policy nft_expr_policy[NFTA_EXPR_MAX + 1] = {
[NFTA_EXPR_NAME] = { .type = NLA_STRING },
[NFTA_EXPR_NAME] = { .type = NLA_STRING,
.len = NFT_MODULE_AUTOLOAD_LIMIT },
[NFTA_EXPR_DATA] = { .type = NLA_NESTED },
};
@ -3931,7 +3935,8 @@ static const struct nla_policy nft_set_elem_policy[NFTA_SET_ELEM_MAX + 1] = {
[NFTA_SET_ELEM_USERDATA] = { .type = NLA_BINARY,
.len = NFT_USERDATA_MAXLEN },
[NFTA_SET_ELEM_EXPR] = { .type = NLA_NESTED },
[NFTA_SET_ELEM_OBJREF] = { .type = NLA_STRING },
[NFTA_SET_ELEM_OBJREF] = { .type = NLA_STRING,
.len = NFT_OBJ_MAXNAMELEN - 1 },
};
static const struct nla_policy nft_set_elem_list_policy[NFTA_SET_ELEM_LIST_MAX + 1] = {