If the lower inode is read-only, don't attempt to open the lower file read/write and don't hand off the open request to the privileged eCryptfs kthread for opening it read/write. Instead, only try an unprivileged, read-only open of the file and give up if that fails. This patch fixes an oops when eCryptfs is mounted on top of a read-only mount.
Cc: Serge Hallyn <[email protected]> Cc: Eric Sandeen <[email protected]> Cc: Dave Kleikamp <[email protected]> Cc: [email protected] Signed-off-by: Tyler Hicks <[email protected]> --- fs/ecryptfs/kthread.c | 24 ++++++++---------------- 1 files changed, 8 insertions(+), 16 deletions(-) diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c index c6d7a4d..e14cf7e 100644 --- a/fs/ecryptfs/kthread.c +++ b/fs/ecryptfs/kthread.c @@ -136,6 +136,7 @@ int ecryptfs_privileged_open(struct file **lower_file, const struct cred *cred) { struct ecryptfs_open_req *req; + int flags = O_LARGEFILE; int rc = 0; /* Corresponding dput() and mntput() are done when the @@ -143,10 +144,14 @@ int ecryptfs_privileged_open(struct file **lower_file, * destroyed. */ dget(lower_dentry); mntget(lower_mnt); - (*lower_file) = dentry_open(lower_dentry, lower_mnt, - (O_RDWR | O_LARGEFILE), cred); + flags |= IS_RDONLY(lower_dentry->d_inode) ? O_RDONLY : O_RDWR; + (*lower_file) = dentry_open(lower_dentry, lower_mnt, flags, cred); if (!IS_ERR(*lower_file)) goto out; + if (flags & O_RDONLY) { + rc = PTR_ERR((*lower_file)); + goto out; + } req = kmem_cache_alloc(ecryptfs_open_req_cache, GFP_KERNEL); if (!req) { rc = -ENOMEM; @@ -180,21 +185,8 @@ int ecryptfs_privileged_open(struct file **lower_file, __func__); goto out_unlock; } - if (IS_ERR(*req->lower_file)) { + if (IS_ERR(*req->lower_file)) rc = PTR_ERR(*req->lower_file); - dget(lower_dentry); - mntget(lower_mnt); - (*lower_file) = dentry_open(lower_dentry, lower_mnt, - (O_RDONLY | O_LARGEFILE), cred); - if (IS_ERR(*lower_file)) { - rc = PTR_ERR(*req->lower_file); - (*lower_file) = NULL; - printk(KERN_WARNING "%s: Error attempting privileged " - "open of lower file with either RW or RO " - "perms; rc = [%d]. Giving up.\n", - __func__, rc); - } - } out_unlock: mutex_unlock(&req->mux); out_free: -- 1.6.2.5 _______________________________________________ Mailing list: https://launchpad.net/~ecryptfs-devel Post to : [email protected] Unsubscribe : https://launchpad.net/~ecryptfs-devel More help : https://help.launchpad.net/ListHelp
