Message ID | 1344279850-90722-1-git-send-email-tim.gardner@canonical.com |
---|---|
State | New |
Headers | show |
On 06/08/12 20:04, Tim Gardner wrote: > From: Tyler Hicks <tyhicks@canonical.com> > > 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 <tyhicks@canonical.com> > Reported-by: Stefan Beller <stefanbeller@googlemail.com> > Cc: John Johansen <john.johansen@canonical.com> > (cherry picked from commit 069ddcda37b2cf5bb4b6031a944c0e9359213262) > --- > fs/ecryptfs/main.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c > index 703cda3..9e3d2ee 100644 > --- a/fs/ecryptfs/main.c > +++ b/fs/ecryptfs/main.c > @@ -505,7 +505,6 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags > goto out; > } > > - s->s_flags = flags; > rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY); > if (rc) > goto out1; > @@ -541,6 +540,15 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags > } > > 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; >
On 08/06/2012 12:04 PM, Tim Gardner wrote: > From: Tyler Hicks <tyhicks@canonical.com> > > 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 looks good to me Ackedy-by: John Johansen <john.johansen@canonical.com>
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index 703cda3..9e3d2ee 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -505,7 +505,6 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags goto out; } - s->s_flags = flags; rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY); if (rc) goto out1; @@ -541,6 +540,15 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags } 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;