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| author | Mimi Zohar | 2018-02-21 17:36:52 +0100 |
|---|---|---|
| committer | Mimi Zohar | 2018-03-23 11:31:37 +0100 |
| commit | 0834136aeaf0e79fc428bfae78340e16719a2a20 (patch) | |
| tree | 9d9540c74833a0de346639d9c37b0da60587ba09 /fs/fuse/inode.c | |
| parent | ima: fail signature verification based on policy (diff) | |
| download | kernel-qcow2-linux-0834136aeaf0e79fc428bfae78340e16719a2a20.tar.gz kernel-qcow2-linux-0834136aeaf0e79fc428bfae78340e16719a2a20.tar.xz kernel-qcow2-linux-0834136aeaf0e79fc428bfae78340e16719a2a20.zip | |
fuse: define the filesystem as untrusted
Files on FUSE can change at any point in time without IMA being able
to detect it. The file data read for the file signature verification
could be totally different from what is subsequently read, making the
signature verification useless.
FUSE can be mounted by unprivileged users either today with fusermount
installed with setuid, or soon with the upcoming patches to allow FUSE
mounts in a non-init user namespace.
This patch sets the SB_I_IMA_UNVERIFIABLE_SIGNATURE flag and when
appropriate sets the SB_I_UNTRUSTED_MOUNTER flag.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Dongsu Park <dongsu@kinvolk.io>
Cc: Alban Crequy <alban@kinvolk.io>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/fuse/inode.c')
| -rw-r--r-- | fs/fuse/inode.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 624f18bbfd2b..ef309958e060 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1080,6 +1080,9 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_time_gran = 1; sb->s_export_op = &fuse_export_operations; + sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; + if (sb->s_user_ns != &init_user_ns) + sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; file = fget(d.fd); err = -EINVAL; |