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authorRobbie Ko <robbieko@synology.com>2018-08-21 11:17:40 +0300
committerTyler Hicks <tyhicks@canonical.com>2019-02-17 02:18:57 +0300
commitd43388dea04b18f516bd7c837d9222fe7309b12d (patch)
tree49ecee9a2b01849ef2cd7d8bb340a6311969f54a /fs/ecryptfs
parent4b47a8b51e7bc0bcd1fa8e546a6333a04ab760d8 (diff)
downloadlinux-d43388dea04b18f516bd7c837d9222fe7309b12d.tar.xz
eCryptfs: fix permission denied with ecryptfs_xattr mount option when create readonly file
When the ecryptfs_xattr mount option is turned on, the ecryptfs metadata will be written to xattr via vfs_setxattr, which will check the WRITE permissions. However, this will cause denial of permission when creating a file withoug write permission. So fix this by calling __vfs_setxattr directly to skip permission check. Signed-off-by: Robbie Ko <robbieko@synology.com> [tyhicks: Copy up lower inode attributes when successful] Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Diffstat (limited to 'fs/ecryptfs')
-rw-r--r--fs/ecryptfs/crypto.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 708f931c36f1..bc2376726090 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -37,6 +37,7 @@
#include <linux/slab.h>
#include <asm/unaligned.h>
#include <linux/kernel.h>
+#include <linux/xattr.h>
#include "ecryptfs_kernel.h"
#define DECRYPT 0
@@ -1131,9 +1132,21 @@ ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
char *page_virt, size_t size)
{
int rc;
+ struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+ struct inode *lower_inode = d_inode(lower_dentry);
- rc = ecryptfs_setxattr(ecryptfs_dentry, ecryptfs_inode,
- ECRYPTFS_XATTR_NAME, page_virt, size, 0);
+ if (!(lower_inode->i_opflags & IOP_XATTR)) {
+ rc = -EOPNOTSUPP;
+ goto out;
+ }
+
+ inode_lock(lower_inode);
+ rc = __vfs_setxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,
+ page_virt, size, 0);
+ if (!rc && ecryptfs_inode)
+ fsstack_copy_attr_all(ecryptfs_inode, lower_inode);
+ inode_unlock(lower_inode);
+out:
return rc;
}