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ANDROID: xt_qtaguid: fix UAF race

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Make sure to hold the sock_tag_list_lock while accessing the tag to
avoid a race between getting the tag and free'ing the tag.

Bug: 184018316
Fixes: c7ca0ac69702 ("ANDROID: netfilter: xt_qtaguid: add qtaguid matching module")
Signed-off-by: Will McVicker <willmcvicker@google.com>
Change-Id: Ia44dfcc1693bc3de1d767e024d09c11f4a8b02f9
Git-commit: 2398e650c58a6f4877dafce649188290f6e3b4f5
Git-repo: https://android.googlesource.com/kernel/msm
Signed-off-by: PavanKumar S.R. <pavasr@codeaurora.org>
This commit is contained in:
Will McVicker 2021-04-13 15:59:41 -07:00 committed by PavanKumar S.R
parent eab193d0d3
commit 06df3cd546
1 changed files with 5 additions and 14 deletions
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19
net/netfilter/xt_qtaguid.c
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@ -1067,18 +1067,6 @@ static struct sock_tag *get_sock_stat_nl(const struct sock *sk)
return sock_tag_tree_search(&sock_tag_tree, sk);
}
static struct sock_tag *get_sock_stat(const struct sock *sk)
{
struct sock_tag *sock_tag_entry;
MT_DEBUG("qtaguid: get_sock_stat(sk=%p)\n", sk);
if (!sk)
return NULL;
spin_lock_bh(&sock_tag_list_lock);
sock_tag_entry = get_sock_stat_nl(sk);
spin_unlock_bh(&sock_tag_list_lock);
return sock_tag_entry;
}
static int ipx_proto(const struct sk_buff *skb,
struct xt_action_param *par)
{
@ -1313,12 +1301,15 @@ static void if_tag_stat_update(const char *ifname, uid_t uid,
* Look for a tagged sock.
* It will have an acct_uid.
*/
sock_tag_entry = get_sock_stat(sk);
spin_lock_bh(&sock_tag_list_lock);
sock_tag_entry = sk ? get_sock_stat_nl(sk) : NULL;
if (sock_tag_entry) {
tag = sock_tag_entry->tag;
acct_tag = get_atag_from_tag(tag);
uid_tag = get_utag_from_tag(tag);
} else {
}
spin_unlock_bh(&sock_tag_list_lock);
if (!sock_tag_entry) {
acct_tag = make_atag_from_value(0);
tag = combine_atag_with_uid(acct_tag, uid);
uid_tag = make_tag_from_uid(uid);