From: Pablo Neira Ayuso pablo@netfilter.org
commit ad9f151e560b016b6ad3280b48e42fa11e1a5440 upstream.
nft_set_elem_expr_alloc() needs an initialized set if expression sets on the NFT_EXPR_GC flag. Move set fields initialization before expression setup.
[4512935.019450] ================================================================== [4512935.019456] BUG: KASAN: null-ptr-deref in nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019487] Read of size 8 at addr 0000000000000070 by task nft/23532 [4512935.019494] CPU: 1 PID: 23532 Comm: nft Not tainted 5.12.0-rc4+ #48 [...] [4512935.019502] Call Trace: [4512935.019505] dump_stack+0x89/0xb4 [4512935.019512] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019536] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019560] kasan_report.cold.12+0x5f/0xd8 [4512935.019566] ? nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019590] nft_set_elem_expr_alloc+0x84/0xd0 [nf_tables] [4512935.019615] nf_tables_newset+0xc7f/0x1460 [nf_tables]
Reported-by: syzbot+ce96ca2b1d0b37c6422d@syzkaller.appspotmail.com Fixes: 65038428b2c6 ("netfilter: nf_tables: allow to specify stateful expression in set definition") Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Florian Westphal fw@strlen.de --- net/netfilter/nf_tables_api.c | 46 ++++++++++++++++++----------------- 1 file changed, 24 insertions(+), 22 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 947d52cff582..3942a29413a4 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4280,15 +4280,7 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, err = nf_tables_set_alloc_name(&ctx, set, name); kfree(name); if (err < 0) - goto err_set_alloc_name; - - if (nla[NFTA_SET_EXPR]) { - expr = nft_set_elem_expr_alloc(&ctx, set, nla[NFTA_SET_EXPR]); - if (IS_ERR(expr)) { - err = PTR_ERR(expr); - goto err_set_alloc_name; - } - } + goto err_set_name;
udata = NULL; if (udlen) { @@ -4299,21 +4291,19 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, INIT_LIST_HEAD(&set->bindings); set->table = table; write_pnet(&set->net, net); - set->ops = ops; + set->ops = ops; set->ktype = ktype; - set->klen = desc.klen; + set->klen = desc.klen; set->dtype = dtype; set->objtype = objtype; - set->dlen = desc.dlen; - set->expr = expr; + set->dlen = desc.dlen; set->flags = flags; - set->size = desc.size; + set->size = desc.size; set->policy = policy; - set->udlen = udlen; - set->udata = udata; + set->udlen = udlen; + set->udata = udata; set->timeout = timeout; set->gc_int = gc_int; - set->handle = nf_tables_alloc_handle(table);
set->field_count = desc.field_count; for (i = 0; i < desc.field_count; i++) @@ -4323,20 +4313,32 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if (err < 0) goto err_set_init;
+ if (nla[NFTA_SET_EXPR]) { + expr = nft_set_elem_expr_alloc(&ctx, set, nla[NFTA_SET_EXPR]); + if (IS_ERR(expr)) { + err = PTR_ERR(expr); + goto err_set_expr_alloc; + } + + set->expr = expr; + } + + set->handle = nf_tables_alloc_handle(table); + err = nft_trans_set_add(&ctx, NFT_MSG_NEWSET, set); if (err < 0) - goto err_set_trans; + goto err_set_expr_alloc;
list_add_tail_rcu(&set->list, &table->sets); table->use++; return 0;
-err_set_trans: +err_set_expr_alloc: + if (set->expr) + nft_expr_destroy(&ctx, set->expr); + ops->destroy(set); err_set_init: - if (expr) - nft_expr_destroy(&ctx, expr); -err_set_alloc_name: kfree(set->name); err_set_name: kvfree(set);