apparmor: move ptrace mediation to more logical task.{h,c}

AppArmor split out task oriented controls to their own logical file
a while ago. Ptrace mediation is better grouped with task than
ipc, so move it.

Signed-off-by: John Johansen <john.johansen@canonical.com>

1 files changed, 114 insertions, 0 deletions

diff --git a/security/apparmor/task.c b/security/apparmor/task.c
index d17130ee6795..503dc0877fb1 100644
--- a/security/apparmor/task.c
+++ b/security/apparmor/task.c
@@ -12,7 +12,12 @@
  * should return to the previous cred if it has not been modified.
  */
 
+#include <linux/gfp.h>
+#include <linux/ptrace.h>
+
+#include "include/audit.h"
 #include "include/cred.h"
+#include "include/policy.h"
 #include "include/task.h"
 
 /**
@@ -177,3 +182,112 @@ int aa_restore_previous_label(u64 token)
 
 	return 0;
 }
+
+/**
+ * audit_ptrace_mask - convert mask to permission string
+ * @mask: permission mask to convert
+ *
+ * Returns: pointer to static string
+ */
+static const char *audit_ptrace_mask(u32 mask)
+{
+	switch (mask) {
+	case MAY_READ:
+		return "read";
+	case MAY_WRITE:
+		return "trace";
+	case AA_MAY_BE_READ:
+		return "readby";
+	case AA_MAY_BE_TRACED:
+		return "tracedby";
+	}
+	return "";
+}
+
+/* call back to audit ptrace fields */
+static void audit_ptrace_cb(struct audit_buffer *ab, void *va)
+{
+	struct common_audit_data *sa = va;
+
+	if (aad(sa)->request & AA_PTRACE_PERM_MASK) {
+		audit_log_format(ab, " requested_mask=\"%s\"",
+				 audit_ptrace_mask(aad(sa)->request));
+
+		if (aad(sa)->denied & AA_PTRACE_PERM_MASK) {
+			audit_log_format(ab, " denied_mask=\"%s\"",
+					 audit_ptrace_mask(aad(sa)->denied));
+		}
+	}
+	audit_log_format(ab, " peer=");
+	aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
+			FLAGS_NONE, GFP_ATOMIC);
+}
+
+/* assumes check for PROFILE_MEDIATES is already done */
+/* TODO: conditionals */
+static int profile_ptrace_perm(struct aa_profile *profile,
+			     struct aa_label *peer, u32 request,
+			     struct common_audit_data *sa)
+{
+	struct aa_perms perms = { };
+
+	aad(sa)->peer = peer;
+	aa_profile_match_label(profile, peer, AA_CLASS_PTRACE, request,
+			       &perms);
+	aa_apply_modes_to_perms(profile, &perms);
+	return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb);
+}
+
+static int profile_tracee_perm(struct aa_profile *tracee,
+			       struct aa_label *tracer, u32 request,
+			       struct common_audit_data *sa)
+{
+	if (profile_unconfined(tracee) || unconfined(tracer) ||
+	    !PROFILE_MEDIATES(tracee, AA_CLASS_PTRACE))
+		return 0;
+
+	return profile_ptrace_perm(tracee, tracer, request, sa);
+}
+
+static int profile_tracer_perm(struct aa_profile *tracer,
+			       struct aa_label *tracee, u32 request,
+			       struct common_audit_data *sa)
+{
+	if (profile_unconfined(tracer))
+		return 0;
+
+	if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE))
+		return profile_ptrace_perm(tracer, tracee, request, sa);
+
+	/* profile uses the old style capability check for ptrace */
+	if (&tracer->label == tracee)
+		return 0;
+
+	aad(sa)->label = &tracer->label;
+	aad(sa)->peer = tracee;
+	aad(sa)->request = 0;
+	aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE,
+				    CAP_OPT_NONE);
+
+	return aa_audit(AUDIT_APPARMOR_AUTO, tracer, sa, audit_ptrace_cb);
+}
+
+/**
+ * aa_may_ptrace - test if tracer task can trace the tracee
+ * @tracer: label of the task doing the tracing  (NOT NULL)
+ * @tracee: task label to be traced
+ * @request: permission request
+ *
+ * Returns: %0 else error code if permission denied or error
+ */
+int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
+		  u32 request)
+{
+	struct aa_profile *profile;
+	u32 xrequest = request << PTRACE_PERM_SHIFT;
+	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE);
+
+	return xcheck_labels(tracer, tracee, profile,
+			profile_tracer_perm(profile, tracee, request, &sa),
+			profile_tracee_perm(profile, tracer, xrequest, &sa));
+}