path: root/security/commoncap.c
diff options
authorSeth Forshee <seth.forshee@canonical.com>2015-09-23 15:16:04 -0500
committerEric W. Biederman <ebiederm@xmission.com>2016-06-24 10:40:31 -0500
commitd07b846f6200454c50d791796edb82660192513d (patch)
tree0addc4233c4e08fc7ca69511761bbd2c7402c1de /security/commoncap.c
parentcc50a07a247e17db76b1f0b0ca06652556e04fa3 (diff)
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/commoncap.c')
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) {

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