From 20523132ec5d1b481e1d66557292ed3a3021e817 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Mon, 23 Jan 2017 17:17:26 +1300
Subject: 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>
---
security/commoncap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/security/commoncap.c b/security/commoncap.c
index feb6044f701d..cbb203c91406 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -548,7 +548,8 @@ skip:
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)) {
--
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