apparmor: pass cred through to audit info.

The cred is needed to properly audit some messages, and will be needed
in the future for uid conditional mediation. So pass it through to
where the apparmor_audit_data struct gets defined.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

1 files changed, 64 insertions, 33 deletions

diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 7f81502019da..d95292a23bcf 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -31,6 +31,7 @@
 
 /**
  * may_change_ptraced_domain - check if can change profile on ptraced task
+ * @cred: cred of task changing domain
  * @to_label: profile to change to  (NOT NULL)
  * @info: message if there is an error
  *
@@ -39,28 +40,34 @@
  *
  * Returns: %0 or error if change not allowed
  */
-static int may_change_ptraced_domain(struct aa_label *to_label,
+static int may_change_ptraced_domain(const struct cred *to_cred,
+				     struct aa_label *to_label,
 				     const char **info)
 {
 	struct task_struct *tracer;
 	struct aa_label *tracerl = NULL;
+	const struct cred *tracer_cred = NULL;
+
 	int error = 0;
 
 	rcu_read_lock();
 	tracer = ptrace_parent(current);
-	if (tracer)
+	if (tracer) {
 		/* released below */
 		tracerl = aa_get_task_label(tracer);
-
+		tracer_cred = get_task_cred(tracer);
+	}
 	/* not ptraced */
 	if (!tracer || unconfined(tracerl))
 		goto out;
 
-	error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
+	error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
+			      PTRACE_MODE_ATTACH);
 
 out:
 	rcu_read_unlock();
 	aa_put_label(tracerl);
+	put_cred(tracer_cred);
 
 	if (error)
 		*info = "ptrace prevents transition";
@@ -621,7 +628,8 @@ static struct aa_label *x_to_label(struct aa_profile *profile,
 	return new;
 }
 
-static struct aa_label *profile_transition(struct aa_profile *profile,
+static struct aa_label *profile_transition(const struct cred *subj_cred,
+					   struct aa_profile *profile,
 					   const struct linux_binprm *bprm,
 					   char *buffer, struct path_cond *cond,
 					   bool *secure_exec)
@@ -711,7 +719,8 @@ static struct aa_label *profile_transition(struct aa_profile *profile,
 	}
 
 audit:
-	aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
+	aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
+		      target, new,
 		      cond->uid, info, error);
 	if (!new || nonewprivs) {
 		aa_put_label(new);
@@ -721,7 +730,8 @@ audit:
 	return new;
 }
 
-static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
+static int profile_onexec(const struct cred *subj_cred,
+			  struct aa_profile *profile, struct aa_label *onexec,
 			  bool stack, const struct linux_binprm *bprm,
 			  char *buffer, struct path_cond *cond,
 			  bool *secure_exec)
@@ -789,13 +799,15 @@ static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
 	}
 
 audit:
-	return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
+	return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
+			     AA_MAY_ONEXEC, xname,
 			     NULL, onexec, cond->uid, info, error);
 }
 
 /* ensure none ns domain transitions are correctly applied with onexec */
 
-static struct aa_label *handle_onexec(struct aa_label *label,
+static struct aa_label *handle_onexec(const struct cred *subj_cred,
+				      struct aa_label *label,
 				      struct aa_label *onexec, bool stack,
 				      const struct linux_binprm *bprm,
 				      char *buffer, struct path_cond *cond,
@@ -812,26 +824,28 @@ static struct aa_label *handle_onexec(struct aa_label *label,
 
 	if (!stack) {
 		error = fn_for_each_in_ns(label, profile,
-				profile_onexec(profile, onexec, stack,
+				profile_onexec(subj_cred, profile, onexec, stack,
 					       bprm, buffer, cond, unsafe));
 		if (error)
 			return ERR_PTR(error);
 		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
 				aa_get_newest_label(onexec),
-				profile_transition(profile, bprm, buffer,
+				profile_transition(subj_cred, profile, bprm,
+						   buffer,
 						   cond, unsafe));
 
 	} else {
 		/* TODO: determine how much we want to loosen this */
 		error = fn_for_each_in_ns(label, profile,
-				profile_onexec(profile, onexec, stack, bprm,
+				profile_onexec(subj_cred, profile, onexec, stack, bprm,
 					       buffer, cond, unsafe));
 		if (error)
 			return ERR_PTR(error);
 		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
 				aa_label_merge(&profile->label, onexec,
 					       GFP_KERNEL),
-				profile_transition(profile, bprm, buffer,
+				profile_transition(subj_cred, profile, bprm,
+						   buffer,
 						   cond, unsafe));
 	}
 
@@ -840,7 +854,8 @@ static struct aa_label *handle_onexec(struct aa_label *label,
 
 	/* TODO: get rid of GLOBAL_ROOT_UID */
 	error = fn_for_each_in_ns(label, profile,
-			aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
+			aa_audit_file(subj_cred, profile, &nullperms,
+				      OP_CHANGE_ONEXEC,
 				      AA_MAY_ONEXEC, bprm->filename, NULL,
 				      onexec, GLOBAL_ROOT_UID,
 				      "failed to build target label", -ENOMEM));
@@ -859,6 +874,7 @@ int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
 {
 	struct aa_task_ctx *ctx;
 	struct aa_label *label, *new = NULL;
+	const struct cred *subj_cred;
 	struct aa_profile *profile;
 	char *buffer = NULL;
 	const char *info = NULL;
@@ -871,6 +887,7 @@ int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
 		file_inode(bprm->file)->i_mode
 	};
 
+	subj_cred = current_cred();
 	ctx = task_ctx(current);
 	AA_BUG(!cred_label(bprm->cred));
 	AA_BUG(!ctx);
@@ -897,11 +914,12 @@ int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
 
 	/* Test for onexec first as onexec override other x transitions. */
 	if (ctx->onexec)
-		new = handle_onexec(label, ctx->onexec, ctx->token,
+		new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
 				    bprm, buffer, &cond, &unsafe);
 	else
 		new = fn_label_build(label, profile, GFP_KERNEL,
-				profile_transition(profile, bprm, buffer,
+				profile_transition(subj_cred, profile, bprm,
+						   buffer,
 						   &cond, &unsafe));
 
 	AA_BUG(!new);
@@ -936,7 +954,7 @@ int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
 
 	if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
 		/* TODO: test needs to be profile of label to new */
-		error = may_change_ptraced_domain(new, &info);
+		error = may_change_ptraced_domain(bprm->cred, new, &info);
 		if (error)
 			goto audit;
 	}
@@ -973,7 +991,8 @@ done:
 
 audit:
 	error = fn_for_each(label, profile,
-			aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
+			aa_audit_file(current_cred(), profile, &nullperms,
+				      OP_EXEC, MAY_EXEC,
 				      bprm->filename, NULL, new,
 				      vfsuid_into_kuid(vfsuid), info, error));
 	aa_put_label(new);
@@ -989,7 +1008,8 @@ audit:
  *
  * Returns: label for hat transition OR ERR_PTR.  Does NOT return NULL
  */
-static struct aa_label *build_change_hat(struct aa_profile *profile,
+static struct aa_label *build_change_hat(const struct cred *subj_cred,
+					 struct aa_profile *profile,
 					 const char *name, bool sibling)
 {
 	struct aa_profile *root, *hat = NULL;
@@ -1021,7 +1041,8 @@ static struct aa_label *build_change_hat(struct aa_profile *profile,
 	aa_put_profile(root);
 
 audit:
-	aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
+	aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
+		      AA_MAY_CHANGEHAT,
 		      name, hat ? hat->base.hname : NULL,
 		      hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
 		      error);
@@ -1037,7 +1058,8 @@ audit:
  *
  * Returns: label for hat transition or ERR_PTR. Does not return NULL
  */
-static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
+static struct aa_label *change_hat(const struct cred *subj_cred,
+				   struct aa_label *label, const char *hats[],
 				   int count, int flags)
 {
 	struct aa_profile *profile, *root, *hat = NULL;
@@ -1113,7 +1135,8 @@ fail:
 		 */
 		/* TODO: get rid of GLOBAL_ROOT_UID */
 		if (count > 1 || COMPLAIN_MODE(profile)) {
-			aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
+			aa_audit_file(subj_cred, profile, &nullperms,
+				      OP_CHANGE_HAT,
 				      AA_MAY_CHANGEHAT, name, NULL, NULL,
 				      GLOBAL_ROOT_UID, info, error);
 		}
@@ -1122,7 +1145,8 @@ fail:
 
 build:
 	new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
-				   build_change_hat(profile, name, sibling),
+				   build_change_hat(subj_cred, profile, name,
+						    sibling),
 				   aa_get_label(&profile->label));
 	if (!new) {
 		info = "label build failed";
@@ -1152,7 +1176,7 @@ build:
  */
 int aa_change_hat(const char *hats[], int count, u64 token, int flags)
 {
-	const struct cred *cred;
+	const struct cred *subj_cred;
 	struct aa_task_ctx *ctx = task_ctx(current);
 	struct aa_label *label, *previous, *new = NULL, *target = NULL;
 	struct aa_profile *profile;
@@ -1161,8 +1185,8 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags)
 	int error = 0;
 
 	/* released below */
-	cred = get_current_cred();
-	label = aa_get_newest_cred_label(cred);
+	subj_cred = get_current_cred();
+	label = aa_get_newest_cred_label(subj_cred);
 	previous = aa_get_newest_label(ctx->previous);
 
 	/*
@@ -1182,7 +1206,7 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags)
 	}
 
 	if (count) {
-		new = change_hat(label, hats, count, flags);
+		new = change_hat(subj_cred, label, hats, count, flags);
 		AA_BUG(!new);
 		if (IS_ERR(new)) {
 			error = PTR_ERR(new);
@@ -1191,7 +1215,8 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags)
 			goto out;
 		}
 
-		error = may_change_ptraced_domain(new, &info);
+		/* target cred is the same as current except new label */
+		error = may_change_ptraced_domain(subj_cred, new, &info);
 		if (error)
 			goto fail;
 
@@ -1244,7 +1269,7 @@ out:
 	aa_put_label(new);
 	aa_put_label(previous);
 	aa_put_label(label);
-	put_cred(cred);
+	put_cred(subj_cred);
 
 	return error;
 
@@ -1254,7 +1279,7 @@ kill:
 
 fail:
 	fn_for_each_in_ns(label, profile,
-		aa_audit_file(profile, &perms, OP_CHANGE_HAT,
+		aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
 			      AA_MAY_CHANGEHAT, NULL, NULL, target,
 			      GLOBAL_ROOT_UID, info, error));
 
@@ -1263,6 +1288,7 @@ fail:
 
 
 static int change_profile_perms_wrapper(const char *op, const char *name,
+					const struct cred *subj_cred,
 					struct aa_profile *profile,
 					struct aa_label *target, bool stack,
 					u32 request, struct aa_perms *perms)
@@ -1277,7 +1303,8 @@ static int change_profile_perms_wrapper(const char *op, const char *name,
 					     rules->file.start[AA_CLASS_FILE],
 					     perms);
 	if (error)
-		error = aa_audit_file(profile, perms, op, request, name,
+		error = aa_audit_file(subj_cred, profile, perms, op, request,
+				      name,
 				      NULL, target, GLOBAL_ROOT_UID, info,
 				      error);
 
@@ -1306,6 +1333,7 @@ int aa_change_profile(const char *fqname, int flags)
 	const char *auditname = fqname;		/* retain leading & if stack */
 	bool stack = flags & AA_CHANGE_STACK;
 	struct aa_task_ctx *ctx = task_ctx(current);
+	const struct cred *subj_cred = get_current_cred();
 	int error = 0;
 	char *op;
 	u32 request;
@@ -1383,6 +1411,7 @@ int aa_change_profile(const char *fqname, int flags)
 	 */
 	error = fn_for_each_in_ns(label, profile,
 			change_profile_perms_wrapper(op, auditname,
+						     subj_cred,
 						     profile, target, stack,
 						     request, &perms));
 	if (error)
@@ -1393,7 +1422,7 @@ int aa_change_profile(const char *fqname, int flags)
 
 check:
 	/* check if tracing task is allowed to trace target domain */
-	error = may_change_ptraced_domain(target, &info);
+	error = may_change_ptraced_domain(subj_cred, target, &info);
 	if (error && !fn_for_each_in_ns(label, profile,
 					COMPLAIN_MODE(profile)))
 		goto audit;
@@ -1453,7 +1482,8 @@ check:
 
 audit:
 	error = fn_for_each_in_ns(label, profile,
-			aa_audit_file(profile, &perms, op, request, auditname,
+			aa_audit_file(subj_cred,
+				      profile, &perms, op, request, auditname,
 				      NULL, new ? new : target,
 				      GLOBAL_ROOT_UID, info, error));
 
@@ -1461,6 +1491,7 @@ out:
 	aa_put_label(new);
 	aa_put_label(target);
 	aa_put_label(label);
+	put_cred(subj_cred);
 
 	return error;
 }