diff options
| author | Manfred Spraul <manfred@colorfullife.com> | 2017-07-12 14:35:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-12 16:26:02 -0700 |
| commit | a2642f8770993a1598500bb6a8082b7c32faff8b (patch) | |
| tree | 426e3190b86cd610744d127ac43df1d8aa19c2a4 | |
| parent | 2ec55f8024db859d70f14c26e91ca044328dd50d (diff) | |
ipc/shm.c: avoid ipc_rcu_putref for failed ipc_addid()
Loosely based on a patch from Kees Cook <keescook@chromium.org>:
- id and error can be merged
- if operations before ipc_addid() fail, then use call_rcu() directly.
The difference is that call_rcu is used for failures after
security_shm_alloc(), to continue to guaranteed an rcu delay for
security_sem_free().
Link: http://lkml.kernel.org/r/20170525185107.12869-15-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | ipc/shm.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 2ac489ef56e4..c5976d318ed1 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -548,7 +548,6 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; struct file *file; char name[13]; - int id; vm_flags_t acctflag = 0; if (size < SHMMIN || size > ns->shm_ctlmax) @@ -617,11 +616,9 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) shp->shm_file = file; shp->shm_creator = current; - id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); - if (id < 0) { - error = id; + error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); + if (error < 0) goto no_id; - } list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist); @@ -643,7 +640,7 @@ no_id: user_shm_unlock(size, shp->mlock_user); fput(file); no_file: - ipc_rcu_putref(&shp->shm_perm, shm_rcu_free); + call_rcu(&shp->shm_perm.rcu, shm_rcu_free); return error; } |