3.11-stable review patch. If anyone has any objections, please let me know.
------------------ From: Davidlohr Bueso <[email protected]> commit c2c737a0461e61a34676bd0bd1bc1a70a1b4e396 upstream. Similar to other system calls, acquire the kern_ipc_perm lock after doing the initial permission and security checks. [[email protected]: dont leave do_shmat with rcu lock held] Signed-off-by: Davidlohr Bueso <[email protected]> Tested-by: Sedat Dilek <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Manfred Spraul <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Cc: Mike Galbraith <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- ipc/shm.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/ipc/shm.c +++ b/ipc/shm.c @@ -19,6 +19,9 @@ * namespaces support * OpenVZ, SWsoft Inc. * Pavel Emelianov <[email protected]> + * + * Better ipc lock (kern_ipc_perm.lock) handling + * Davidlohr Bueso <[email protected]>, June 2013. */ #include <linux/slab.h> @@ -1093,10 +1096,11 @@ long do_shmat(int shmid, char __user *sh * additional creator id... */ ns = current->nsproxy->ipc_ns; - shp = shm_lock_check(ns, shmid); + rcu_read_lock(); + shp = shm_obtain_object_check(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); - goto out; + goto out_unlock; } err = -EACCES; @@ -1107,11 +1111,13 @@ long do_shmat(int shmid, char __user *sh if (err) goto out_unlock; + ipc_lock_object(&shp->shm_perm); path = shp->shm_file->f_path; path_get(&path); shp->shm_nattch++; size = i_size_read(path.dentry->d_inode); - shm_unlock(shp); + ipc_unlock_object(&shp->shm_perm); + rcu_read_unlock(); err = -ENOMEM; sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); @@ -1182,7 +1188,7 @@ out_nattch: return err; out_unlock: - shm_unlock(shp); + rcu_read_unlock(); out: return err; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
