diff options
| author | Pedro Tammela <pctammela@mojatatu.com> | 2023-04-15 12:33:09 -0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-04-17 10:06:23 +0100 |
| commit | 338469d677e5d426f5ada88761f16f6d2c7c1981 (patch) | |
| tree | f2aa7b9d48f5734235ec273ffde17d5a98cdd0e9 /net/sched/cls_api.c | |
| parent | a80bb8e7233b2ad6ff119646b6e33fb3edcec37b (diff) | |
net/sched: clear actions pointer in miss cookie init fail
Palash reports a UAF when using a modified version of syzkaller[1].
When 'tcf_exts_miss_cookie_base_alloc()' fails in 'tcf_exts_init_ex()'
a call to 'tcf_exts_destroy()' is made to free up the tcf_exts
resources.
In flower, a call to '__fl_put()' when 'tcf_exts_init_ex()' fails is made;
Then calling 'tcf_exts_destroy()', which triggers an UAF since the
already freed tcf_exts action pointer is lingering in the struct.
Before the offending patch, this was not an issue since there was no
case where the tcf_exts action pointer could linger. Therefore, restore
the old semantic by clearing the action pointer in case of a failure to
initialize the miss_cookie.
[1] https://github.com/cmu-pasta/linux-kernel-enriched-corpus
v1->v2: Fix compilation on configs without tc actions (kernel test robot)
Fixes: 80cd22c35c90 ("net/sched: cls_api: Support hardware miss to tc action")
Reported-by: Palash Oswal <oswalpalash@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/cls_api.c')
| -rw-r--r-- | net/sched/cls_api.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 2a6b6be0811b..35785a36c802 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3235,6 +3235,9 @@ int tcf_exts_init_ex(struct tcf_exts *exts, struct net *net, int action, err_miss_alloc: tcf_exts_destroy(exts); +#ifdef CONFIG_NET_CLS_ACT + exts->actions = NULL; +#endif return err; } EXPORT_SYMBOL(tcf_exts_init_ex); |