iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

netfilter: nft_ct: fix use after free when attaching zone template

Browse Source 
commit 34243b9ec856309339172b1507379074156947e8 upstream.

The conversion erroneously removed the refcount increment.
In case we can use the percpu template, we need to increment
the refcount, else it will be released when the skb gets freed.

In case the slowpath is taken, the new template already has a
refcount of 1.

Fixes: 719774377622 ("netfilter: conntrack: convert to refcount_t api")
Reported-by: kernel test robot <oliver.sang@intel.com>
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 2022-01-23 15:24:00 +01:00 committed by Greg Kroah-Hartman
parent 2b273d1fd1
commit 2e25c46c6e
1 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
net/netfilter/nft_ct.c
View File

@ -260,9 +260,12 @@ static void nft_ct_set_zone_eval(const struct nft_expr *expr,
ct = this_cpu_read(nft_ct_pcpu_template);
if (likely(refcount_read(&ct->ct_general.use) == 1)) {
refcount_inc(&ct->ct_general.use);
nf_ct_zone_add(ct, &zone);
} else {
/* previous skb got queued to userspace */
/* previous skb got queued to userspace, allocate temporary
* one until percpu template can be reused.
*/
ct = nf_ct_tmpl_alloc(nft_net(pkt), &zone, GFP_ATOMIC);
if (!ct) {
regs->verdict.code = NF_DROP;