diff options
| author | Seth Forshee <[email protected]> | 2015-09-23 20:16:04 +0000 |
|---|---|---|
| committer | Eric W. Biederman <[email protected]> | 2016-06-24 15:40:31 +0000 |
| commit | d07b846f6200454c50d791796edb82660192513d (patch) | |
| tree | 0addc4233c4e08fc7ca69511761bbd2c7402c1de /security/commoncap.c | |
| parent | userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag (diff) | |
| download | kernel-d07b846f6200454c50d791796edb82660192513d.tar.gz kernel-d07b846f6200454c50d791796edb82660192513d.zip | |
fs: Limit file caps to the user namespace of the super block
Capability sets attached to files must be ignored except in the
user namespaces where the mounter is privileged, i.e. s_user_ns
and its descendants. Otherwise a vector exists for gaining
privileges in namespaces where a user is not already privileged.
Add a new helper function, current_in_user_ns(), to test whether a user
namespace is the same as or a descendant of another namespace.
Use this helper to determine whether a file's capability set
should be applied to the caps constructed during exec.
--EWB Replaced in_userns with the simpler current_in_userns.
Acked-by: Serge Hallyn <[email protected]>
Signed-off-by: Seth Forshee <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
Diffstat (limited to 'security/commoncap.c')
| -rw-r--r-- | security/commoncap.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index e7fadde737f4..e109e6dac858 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -455,6 +455,8 @@ static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_c if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) return 0; + if (!current_in_userns(bprm->file->f_path.mnt->mnt_sb->s_user_ns)) + return 0; rc = get_vfs_caps_from_disk(bprm->file->f_path.dentry, &vcaps); if (rc < 0) { |