3.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Tyler Hicks <tyhi...@canonical.com> commit 069ddcda37b2cf5bb4b6031a944c0e9359213262 upstream. When the eCryptfs mount options do not include '-o acl', but the lower filesystem's mount options do include 'acl', the MS_POSIXACL flag is not flipped on in the eCryptfs super block flags. This flag is what the VFS checks in do_last() when deciding if the current umask should be applied to a newly created inode's mode or not. When a default POSIX ACL mask is set on a directory, the current umask is incorrectly applied to new inodes created in the directory. This patch ignores the MS_POSIXACL flag passed into ecryptfs_mount() and sets the flag on the eCryptfs super block depending on the flag's presence on the lower super block. Additionally, it is incorrect to allow a writeable eCryptfs mount on top of a read-only lower mount. This missing check did not allow writes to the read-only lower mount because permissions checks are still performed on the lower filesystem's objects but it is best to simply not allow a rw mount on top of ro mount. However, a ro eCryptfs mount on top of a rw mount is valid and still allowed. https://launchpad.net/bugs/1009207 Signed-off-by: Tyler Hicks <tyhi...@canonical.com> Reported-by: Stefan Beller <stefanbel...@googlemail.com> Cc: John Johansen <john.johan...@canonical.com> Cc: Herton Ronaldo Krzesinski <herton.krzesin...@canonical.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- fs/ecryptfs/main.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -506,7 +506,6 @@ static struct dentry *ecryptfs_mount(str goto out; } - s->s_flags = flags; rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY); if (rc) goto out1; @@ -542,6 +541,15 @@ static struct dentry *ecryptfs_mount(str } ecryptfs_set_superblock_lower(s, path.dentry->d_sb); + + /** + * Set the POSIX ACL flag based on whether they're enabled in the lower + * mount. Force a read-only eCryptfs mount if the lower mount is ro. + * Allow a ro eCryptfs mount even when the lower mount is rw. + */ + s->s_flags = flags & ~MS_POSIXACL; + s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL); + s->s_maxbytes = path.dentry->d_sb->s_maxbytes; s->s_blocksize = path.dentry->d_sb->s_blocksize; s->s_magic = ECRYPTFS_SUPER_MAGIC; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
