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| author | Jeongjun Park <aha310510@gmail.com> | 2025-04-24 23:33:22 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-27 11:08:49 +0100 |
| commit | 5180561afff8e0f029073c8c8117c95c6512d1f9 (patch) | |
| tree | d31d6331e8655551c35f456518fe3ccde46bc36a /ipc | |
| parent | f24d422452398e5d2b3461e081a2ac617d696701 (diff) | |
| download | linux-5180561afff8e0f029073c8c8117c95c6512d1f9.tar.gz linux-5180561afff8e0f029073c8c8117c95c6512d1f9.tar.bz2 linux-5180561afff8e0f029073c8c8117c95c6512d1f9.zip | |
ipc: fix to protect IPCS lookups using RCU
commit d66adabe91803ef34a8b90613c81267b5ded1472 upstream.
syzbot reported that it discovered a use-after-free vulnerability, [0]
[0]: https://lore.kernel.org/all/67af13f8.050a0220.21dd3.0038.GAE@google.com/
idr_for_each() is protected by rwsem, but this is not enough. If it is
not protected by RCU read-critical region, when idr_for_each() calls
radix_tree_node_free() through call_rcu() to free the radix_tree_node
structure, the node will be freed immediately, and when reading the next
node in radix_tree_for_each_slot(), the already freed memory may be read.
Therefore, we need to add code to make sure that idr_for_each() is
protected within the RCU read-critical region when we call it in
shm_destroy_orphaned().
Link: https://lkml.kernel.org/r/20250424143322.18830-1-aha310510@gmail.com
Fixes: b34a6b1da371 ("ipc: introduce shm_rmid_forced sysctl")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Reported-by: syzbot+a2b84e569d06ca3a949c@syzkaller.appspotmail.com
Cc: Jeongjun Park <aha310510@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/shm.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 576a543b7cff..c4845689b7f6 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -430,8 +430,11 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data) void shm_destroy_orphaned(struct ipc_namespace *ns) { down_write(&shm_ids(ns).rwsem); - if (shm_ids(ns).in_use) + if (shm_ids(ns).in_use) { + rcu_read_lock(); idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns); + rcu_read_unlock(); + } up_write(&shm_ids(ns).rwsem); } |