Merge tag 'apparmor-pr-2017-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

Pull apparmor updates from John Johansen:
 "This is the apparmor pull request, similar to SELinux and seccomp.

  It's the same series that I was sent to James' security tree + one
  regression fix that was found after the series was sent to James and
  would have been sent for v4.14-rc2.

  Features:
  - in preparation for secid mapping add support for absolute root view
    based labels
  - add base infastructure for socket mediation
  - add mount mediation
  - add signal mediation

  minor cleanups and changes:
  - be defensive, ensure unconfined profiles have dfas initialized
  - add more debug asserts to apparmorfs
  - enable policy unpacking to audit different reasons for failure
  - cleanup conditional check for label in label_print
  - Redundant condition: prev_ns. in [label.c:1498]

  Bug Fixes:
  - fix regression in apparmorfs DAC access permissions
  - fix build failure on sparc caused by undeclared signals
  - fix sparse report of incorrect type assignment when freeing label proxies
  - fix race condition in null profile creation
  - Fix an error code in aafs_create()
  - Fix logical error in verify_header()
  - Fix shadowed local variable in unpack_trans_table()"

* tag 'apparmor-pr-2017-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
  apparmor: fix apparmorfs DAC access permissions
  apparmor: fix build failure on sparc caused by undeclared signals
  apparmor: fix incorrect type assignment when freeing proxies
  apparmor: ensure unconfined profiles have dfas initialized
  apparmor: fix race condition in null profile creation
  apparmor: move new_null_profile to after profile lookup fns()
  apparmor: add base infastructure for socket mediation
  apparmor: add more debug asserts to apparmorfs
  apparmor: make policy_unpack able to audit different info messages
  apparmor: add support for absolute root view based labels
  apparmor: cleanup conditional check for label in label_print
  apparmor: add mount mediation
  apparmor: add the ability to mediate signals
  apparmor: Redundant condition: prev_ns. in [label.c:1498]
  apparmor: Fix an error code in aafs_create()
  apparmor: Fix logical error in verify_header()
  apparmor: Fix shadowed local variable in unpack_trans_table()

1 files changed, 99 insertions, 0 deletions

diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c
index 11e66b5bbc42..66fb9ede9447 100644
--- a/security/apparmor/ipc.c
+++ b/security/apparmor/ipc.c
@@ -20,6 +20,7 @@
 #include "include/context.h"
 #include "include/policy.h"
 #include "include/ipc.h"
+#include "include/sig_names.h"
 
 /**
  * audit_ptrace_mask - convert mask to permission string
@@ -121,3 +122,101 @@ int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
 }
 
 
+static inline int map_signal_num(int sig)
+{
+	if (sig > SIGRTMAX)
+		return SIGUNKNOWN;
+	else if (sig >= SIGRTMIN)
+		return sig - SIGRTMIN + 128;	/* rt sigs mapped to 128 */
+	else if (sig <= MAXMAPPED_SIG)
+		return sig_map[sig];
+	return SIGUNKNOWN;
+}
+
+/**
+ * audit_file_mask - convert mask to permission string
+ * @buffer: buffer to write string to (NOT NULL)
+ * @mask: permission mask to convert
+ */
+static void audit_signal_mask(struct audit_buffer *ab, u32 mask)
+{
+	if (mask & MAY_READ)
+		audit_log_string(ab, "receive");
+	if (mask & MAY_WRITE)
+		audit_log_string(ab, "send");
+}
+
+/**
+ * audit_cb - call back for signal specific audit fields
+ * @ab: audit_buffer  (NOT NULL)
+ * @va: audit struct to audit values of  (NOT NULL)
+ */
+static void audit_signal_cb(struct audit_buffer *ab, void *va)
+{
+	struct common_audit_data *sa = va;
+
+	if (aad(sa)->request & AA_SIGNAL_PERM_MASK) {
+		audit_log_format(ab, " requested_mask=");
+		audit_signal_mask(ab, aad(sa)->request);
+		if (aad(sa)->denied & AA_SIGNAL_PERM_MASK) {
+			audit_log_format(ab, " denied_mask=");
+			audit_signal_mask(ab, aad(sa)->denied);
+		}
+	}
+	if (aad(sa)->signal <= MAXMAPPED_SIG)
+		audit_log_format(ab, " signal=%s", sig_names[aad(sa)->signal]);
+	else
+		audit_log_format(ab, " signal=rtmin+%d",
+				 aad(sa)->signal - 128);
+	audit_log_format(ab, " peer=");
+	aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
+			FLAGS_NONE, GFP_ATOMIC);
+}
+
+/* TODO: update to handle compound name&name2, conditionals */
+static void profile_match_signal(struct aa_profile *profile, const char *label,
+				 int signal, struct aa_perms *perms)
+{
+	unsigned int state;
+
+	/* TODO: secondary cache check <profile, profile, perm> */
+	state = aa_dfa_next(profile->policy.dfa,
+			    profile->policy.start[AA_CLASS_SIGNAL],
+			    signal);
+	state = aa_dfa_match(profile->policy.dfa, state, label);
+	aa_compute_perms(profile->policy.dfa, state, perms);
+}
+
+static int profile_signal_perm(struct aa_profile *profile,
+			       struct aa_profile *peer, u32 request,
+			       struct common_audit_data *sa)
+{
+	struct aa_perms perms;
+
+	if (profile_unconfined(profile) ||
+	    !PROFILE_MEDIATES(profile, AA_CLASS_SIGNAL))
+		return 0;
+
+	aad(sa)->peer = &peer->label;
+	profile_match_signal(profile, peer->base.hname, aad(sa)->signal,
+			     &perms);
+	aa_apply_modes_to_perms(profile, &perms);
+	return aa_check_perms(profile, &perms, request, sa, audit_signal_cb);
+}
+
+static int aa_signal_cross_perm(struct aa_profile *sender,
+				struct aa_profile *target,
+				struct common_audit_data *sa)
+{
+	return xcheck(profile_signal_perm(sender, target, MAY_WRITE, sa),
+		      profile_signal_perm(target, sender, MAY_READ, sa));
+}
+
+int aa_may_signal(struct aa_label *sender, struct aa_label *target, int sig)
+{
+	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SIGNAL);
+
+	aad(&sa)->signal = map_signal_num(sig);
+	return xcheck_labels_profiles(sender, target, aa_signal_cross_perm,
+				      &sa);
+}