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authorManfred Spraul <manfred@colorfullife.com>2017-07-12 14:35:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-12 16:26:02 -0700
commita2642f8770993a1598500bb6a8082b7c32faff8b (patch)
tree426e3190b86cd610744d127ac43df1d8aa19c2a4 /ipc/shm.c
parent2ec55f8024db859d70f14c26e91ca044328dd50d (diff)
download96b-common-a2642f8770993a1598500bb6a8082b7c32faff8b.tar.gz
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>
Diffstat (limited to 'ipc/shm.c')
-rw-r--r--ipc/shm.c9
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, &current->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;
}