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);
+}