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| author | Tyler Hicks <tyhicks@linux.vnet.ibm.com> | 2009-08-12 01:06:54 -0500 |
|---|---|---|
| committer | Tyler Hicks <tyhicks@linux.vnet.ibm.com> | 2009-09-23 09:10:32 -0500 |
| commit | ac22ba23b659e34a5961aec8c945608e471b0d5b (patch) | |
| tree | 6629c15380fe2db238fa078e912f4cf393708161 /fs/ecryptfs/kthread.c | |
| parent | b0105eaefa7cce8f4a941d0fc6354b250d30e745 (diff) | |
| download | linux-ac22ba23b659e34a5961aec8c945608e471b0d5b.tar.gz linux-ac22ba23b659e34a5961aec8c945608e471b0d5b.tar.bz2 linux-ac22ba23b659e34a5961aec8c945608e471b0d5b.zip | |
eCryptfs: Check for O_RDONLY lower inodes when opening lower files
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.
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Eric Sandeen <esandeen@redhat.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Cc: stable <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Diffstat (limited to 'fs/ecryptfs/kthread.c')
| -rw-r--r-- | 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 c6d7a4d748a0..e14cf7e588db 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: |