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netfilter: nf_tables: initialize set before expression setup

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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: 65038428b2 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Pablo Neira Ayuso 2021-09-09 16:03:36 +02:00 committed by Greg Kroah-Hartman
parent 3fda454f90
commit 36983fc2f8
1 changed files with 24 additions and 22 deletions
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46
net/netfilter/nf_tables_api.c
View File

@ -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);