Suren Baghdasaryan d3e4c61e14 psi: Fix uaf issue when psi trigger is destroyed while being polled ... commit a06247c680 upstream. With write operation on psi files replacing old trigger with a new one, the lifetime of its waitqueue is totally arbitrary. Overwriting an existing trigger causes its waitqueue to be freed and pending poll() will stumble on trigger->event_wait which was destroyed. Fix this by disallowing to redefine an existing psi trigger. If a write operation is used on a file descriptor with an already existing psi trigger, the operation will fail with EBUSY error. Also bypass a check for psi_disabled in the psi_trigger_destroy as the flag can be flipped after the trigger is created, leading to a memory leak. Fixes: 0e94682b73 ("psi: introduce psi monitor") Reported-by: syzbot+cdb5dd11c97cc532efad@syzkaller.appspotmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Analyzed-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220111232309.1786347-1-surenb@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-02-01 17:27:01 +01:00
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Makefile	cgroup: Add misc cgroup controller	2021-04-04 13:34:46 -04:00
cgroup-internal.h	cgroup: Use open-time cgroup namespace for process migration perm checks	2022-01-11 15:35:15 +01:00
cgroup-v1.c	cgroup: Allocate cgroup_file_ctx for kernfs_open_file->priv	2022-01-11 15:35:15 +01:00
cgroup.c	psi: Fix uaf issue when psi trigger is destroyed while being polled	2022-02-01 17:27:01 +01:00
cpuset.c	cgroup/cpuset: Change references of cpuset_mutex to cpuset_rwsem	2021-09-13 08:06:17 -10:00
debug.c	…
freezer.c	cgroup: freezer: don't change task and cgroups status unnecessarily	2019-11-07 07:38:41 -08:00
legacy_freezer.c	…
misc.c	svm/sev: Register SEV and SEV-ES ASIDs to the misc controller	2021-04-04 13:34:46 -04:00
namespace.c	memcg: enable accounting for new namesapces and struct nsproxy	2021-09-03 09:58:12 -07:00
pids.c	clone3: allow spawning processes into cgroups	2020-02-12 17:57:51 -05:00
rdma.c	cgroup: fix spelling mistakes	2021-05-24 12:45:26 -04:00
rstat.c	cgroup: Fix rootcg cpu.stat guest double counting	2021-11-18 19:16:45 +01:00