From ad9f151e560b016b6ad3280b48e42fa11e1a5440 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 4 Jun 2021 03:07:28 +0200 Subject: [PATCH] netfilter: nf_tables: initialize set before expression setup 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 --- net/netfilter/nf_tables_api.c | 101 +++++++++++++++++----------------- 1 file changed, 51 insertions(+), 50 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 72bc759179ef..bf4d6ec9fc55 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4364,44 +4364,7 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info, 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; - } - set->exprs[0] = expr; - set->num_exprs++; - } else if (nla[NFTA_SET_EXPRESSIONS]) { - struct nft_expr *expr; - struct nlattr *tmp; - int left; - - if (!(flags & NFT_SET_EXPR)) { - err = -EINVAL; - goto err_set_alloc_name; - } - i = 0; - nla_for_each_nested(tmp, nla[NFTA_SET_EXPRESSIONS], left) { - if (i == NFT_SET_EXPR_MAX) { - err = -E2BIG; - goto err_set_init; - } - if (nla_type(tmp) != NFTA_LIST_ELEM) { - err = -EINVAL; - goto err_set_init; - } - expr = nft_set_elem_expr_alloc(&ctx, set, tmp); - if (IS_ERR(expr)) { - err = PTR_ERR(expr); - goto err_set_init; - } - set->exprs[i++] = expr; - set->num_exprs++; - } - } + goto err_set_name; udata = NULL; if (udlen) { @@ -4413,20 +4376,19 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info, INIT_LIST_HEAD(&set->catchall_list); 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->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++) @@ -4436,20 +4398,59 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info, 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->exprs[0] = expr; + set->num_exprs++; + } else if (nla[NFTA_SET_EXPRESSIONS]) { + struct nft_expr *expr; + struct nlattr *tmp; + int left; + + if (!(flags & NFT_SET_EXPR)) { + err = -EINVAL; + goto err_set_expr_alloc; + } + i = 0; + nla_for_each_nested(tmp, nla[NFTA_SET_EXPRESSIONS], left) { + if (i == NFT_SET_EXPR_MAX) { + err = -E2BIG; + goto err_set_expr_alloc; + } + if (nla_type(tmp) != NFTA_LIST_ELEM) { + err = -EINVAL; + goto err_set_expr_alloc; + } + expr = nft_set_elem_expr_alloc(&ctx, set, tmp); + if (IS_ERR(expr)) { + err = PTR_ERR(expr); + goto err_set_expr_alloc; + } + set->exprs[i++] = expr; + set->num_exprs++; + } + } + + 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: - ops->destroy(set); -err_set_init: +err_set_expr_alloc: for (i = 0; i < set->num_exprs; i++) nft_expr_destroy(&ctx, set->exprs[i]); -err_set_alloc_name: + + ops->destroy(set); +err_set_init: kfree(set->name); err_set_name: kvfree(set);