Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 26c5606f authored by Mickaël Salaün's avatar Mickaël Salaün Committed by Greg Kroah-Hartman
Browse files

ptrace: Set PF_SUPERPRIV when checking capability 



commit cf23705244c947151179f929774fabf71e239eee upstream.

Commit 69f594a3 ("ptrace: do not audit capability check when outputing
/proc/pid/stat") replaced the use of ns_capable() with
has_ns_capability{,_noaudit}() which doesn't set PF_SUPERPRIV.

Commit 6b3ad6649a4c ("ptrace: reintroduce usage of subjective credentials in
ptrace_has_cap()") replaced has_ns_capability{,_noaudit}() with
security_capable(), which doesn't set PF_SUPERPRIV neither.

Since commit 98f368e9 ("kernel: Add noaudit variant of ns_capable()"), a
new ns_capable_noaudit() helper is available.  Let's use it!

As a result, the signature of ptrace_has_cap() is restored to its original one.

Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: stable@vger.kernel.org
Fixes: 6b3ad6649a4c ("ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()")
Fixes: 69f594a3 ("ptrace: do not audit capability check when outputing /proc/pid/stat")
Signed-off-by: default avatarMickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: default avatarJann Horn <jannh@google.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201030123849.770769-2-mic@digikod.net


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 497fc376

kernel/ptrace.c

+5 −11
Original line number Original line Diff line number Diff line
@@ -258,17 +258,11 @@ static int ptrace_check_attach(struct task_struct *child, bool ignore_state) 
	return ret;

	return ret;

}

}





static bool ptrace_has_cap(const struct cred *cred, struct user_namespace *ns,

static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)

			   unsigned int mode)

{

{

	int ret;



	if (mode & PTRACE_MODE_NOAUDIT)

	if (mode & PTRACE_MODE_NOAUDIT)

		ret = security_capable(cred, ns, CAP_SYS_PTRACE, CAP_OPT_NOAUDIT);

		return ns_capable_noaudit(ns, CAP_SYS_PTRACE);

	else

	return ns_capable(ns, CAP_SYS_PTRACE);

		ret = security_capable(cred, ns, CAP_SYS_PTRACE, CAP_OPT_NONE);



	return ret == 0;

}

}





/* Returns 0 on success, -errno on denial. */

/* Returns 0 on success, -errno on denial. */
@@ -320,7 +314,7 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 
	    gid_eq(caller_gid, tcred->sgid) &&

	    gid_eq(caller_gid, tcred->sgid) &&

	    gid_eq(caller_gid, tcred->gid))

	    gid_eq(caller_gid, tcred->gid))

		goto ok;

		goto ok;

	if (ptrace_has_cap(cred, tcred->user_ns, mode))

	if (ptrace_has_cap(tcred->user_ns, mode))

		goto ok;

		goto ok;

	rcu_read_unlock();

	rcu_read_unlock();

	return -EPERM;

	return -EPERM;
@@ -339,7 +333,7 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode) 
	mm = task->mm;

	mm = task->mm;

	if (mm &&

	if (mm &&

	    ((get_dumpable(mm) != SUID_DUMP_USER) &&

	    ((get_dumpable(mm) != SUID_DUMP_USER) &&

	     !ptrace_has_cap(cred, mm->user_ns, mode)))

	     !ptrace_has_cap(mm->user_ns, mode)))

	    return -EPERM;

	    return -EPERM;





	return security_ptrace_access_check(task, mode);

	return security_ptrace_access_check(task, mode);