Commit 20523132 authored Jan 23, 2017 by Eric W. Biederman

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>

parent 70169420

security/commoncap.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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)) {