exec: Test the ptracer's saved cred to see if the tracee can gain caps
Now that we have user namespaces and non-global capabilities verify
the tracer has capabilities in the relevant user namespace instead
of in the current_user_ns().
As the test for setting LSM_UNSAFE_PTRACE_CAP is currently
ptracer_capable(p, current_user_ns()) and the new task credentials are
in current_user_ns() this change does not have any user visible change
and simply moves the test to where it is used, making the code easier
to read.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/security/commoncap.c b/security/commoncap.c
index feb6044..cbb203c 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -548,7 +548,8 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
if ((is_setid ||
!cap_issubset(new->cap_permitted, old->cap_permitted)) &&
- bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
+ ((bprm->unsafe & ~(LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) ||
+ !ptracer_capable(current, new->user_ns))) {
/* downgrade; they get no more than they had, and maybe less */
if (!ns_capable(new->user_ns, CAP_SETUID) ||
(bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)) {