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| author | Christian Brauner <christian.brauner@ubuntu.com> | 2021-01-21 14:19:23 +0100 |
|---|---|---|
| committer | Christian Brauner <christian.brauner@ubuntu.com> | 2021-01-24 14:27:16 +0100 |
| commit | 0558c1bf5a0811bf5e3753eed911a15b9bd08271 (patch) | |
| tree | bbaad2c11479beaac5328c5c3eb33241f9b3cc45 /security/commoncap.c | |
| parent | 02f92b3868a1b34ab98464e76b0e4e060474ba10 (diff) | |
| download | linux-0558c1bf5a0811bf5e3753eed911a15b9bd08271.tar.gz linux-0558c1bf5a0811bf5e3753eed911a15b9bd08271.tar.bz2 linux-0558c1bf5a0811bf5e3753eed911a15b9bd08271.zip | |
capability: handle idmapped mounts
In order to determine whether a caller holds privilege over a given
inode the capability framework exposes the two helpers
privileged_wrt_inode_uidgid() and capable_wrt_inode_uidgid(). The former
verifies that the inode has a mapping in the caller's user namespace and
the latter additionally verifies that the caller has the requested
capability in their current user namespace.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped inodes. If the initial user namespace is passed all
operations are a nop so non-idmapped mounts will not see a change in
behavior.
Link: https://lore.kernel.org/r/20210121131959.646623-5-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Diffstat (limited to 'security/commoncap.c')
| -rw-r--r-- | security/commoncap.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index bacc1111d871..88ee345f7bfa 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -489,7 +489,7 @@ int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size) return -EINVAL; if (!validheader(size, cap)) return -EINVAL; - if (!capable_wrt_inode_uidgid(inode, CAP_SETFCAP)) + if (!capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_SETFCAP)) return -EPERM; if (size == XATTR_CAPS_SZ_2) if (ns_capable(inode->i_sb->s_user_ns, CAP_SETFCAP)) @@ -956,7 +956,8 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name) struct inode *inode = d_backing_inode(dentry); if (!inode) return -EINVAL; - if (!capable_wrt_inode_uidgid(inode, CAP_SETFCAP)) + if (!capable_wrt_inode_uidgid(&init_user_ns, inode, + CAP_SETFCAP)) return -EPERM; return 0; } |