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| author | Seth Forshee <seth.forshee@canonical.com> | 2015-09-23 23:16:04 +0300 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2016-06-24 18:40:31 +0300 |
| commit | d07b846f6200454c50d791796edb82660192513d (patch) | |
| tree | 0addc4233c4e08fc7ca69511761bbd2c7402c1de /security | |
| parent | cc50a07a247e17db76b1f0b0ca06652556e04fa3 (diff) | |
| download | linux-d07b846f6200454c50d791796edb82660192513d.tar.xz | |
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 <serge.hallyn@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'security')
| -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) { |