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| author | Eric Dumazet <edumazet@google.com> | 2022-02-04 23:42:35 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-02-05 16:22:44 +0100 |
| commit | e3ececfe668facd87d920b608349a32607060e66 (patch) | |
| tree | 99cee105c8bf97b641e5d1121e8a778c0c5149d3 | |
| parent | Merge branch 'ipv6-mc_forwarding-changes' (diff) | |
| download | linux-e3ececfe668facd87d920b608349a32607060e66.tar.xz linux-e3ececfe668facd87d920b608349a32607060e66.zip | |
ref_tracker: implement use-after-free detection
Whenever ref_tracker_dir_init() is called, mark the struct ref_tracker_dir
as dead.
Test the dead status from ref_tracker_alloc() and ref_tracker_free()
This should detect buggy dev_put()/dev_hold() happening too late
in netdevice dismantle process.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/ref_tracker.h | 2 | ||||
| -rw-r--r-- | lib/ref_tracker.c | 5 |
2 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h index 60f3453be23e..a443abda937d 100644 --- a/include/linux/ref_tracker.h +++ b/include/linux/ref_tracker.h @@ -13,6 +13,7 @@ struct ref_tracker_dir { spinlock_t lock; unsigned int quarantine_avail; refcount_t untracked; + bool dead; struct list_head list; /* List of active trackers */ struct list_head quarantine; /* List of dead trackers */ #endif @@ -26,6 +27,7 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir, INIT_LIST_HEAD(&dir->quarantine); spin_lock_init(&dir->lock); dir->quarantine_avail = quarantine_count; + dir->dead = false; refcount_set(&dir->untracked, 1); stack_depot_init(); } diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c index a6789c0c626b..32ff6bd497f8 100644 --- a/lib/ref_tracker.c +++ b/lib/ref_tracker.c @@ -20,6 +20,7 @@ void ref_tracker_dir_exit(struct ref_tracker_dir *dir) unsigned long flags; bool leak = false; + dir->dead = true; spin_lock_irqsave(&dir->lock, flags); list_for_each_entry_safe(tracker, n, &dir->quarantine, head) { list_del(&tracker->head); @@ -72,6 +73,8 @@ int ref_tracker_alloc(struct ref_tracker_dir *dir, gfp_t gfp_mask = gfp; unsigned long flags; + WARN_ON_ONCE(dir->dead); + if (gfp & __GFP_DIRECT_RECLAIM) gfp_mask |= __GFP_NOFAIL; *trackerp = tracker = kzalloc(sizeof(*tracker), gfp_mask); @@ -100,6 +103,8 @@ int ref_tracker_free(struct ref_tracker_dir *dir, unsigned int nr_entries; unsigned long flags; + WARN_ON_ONCE(dir->dead); + if (!tracker) { refcount_dec(&dir->untracked); return -EEXIST; |