1 files changed, 86 insertions, 105 deletions

diff --git a/security/apparmor/path.c b/security/apparmor/path.c
index 35b394a75d76..d6c74c357ffd 100644
--- a/security/apparmor/path.c
+++ b/security/apparmor/path.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * AppArmor security module
  *
@@ -5,11 +6,6 @@
  *
  * Copyright (C) 1998-2008 Novell/SUSE
  * Copyright 2009-2010 Canonical Ltd.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation, version 2 of the
- * License.
  */
 
 #include <linux/magic.h>
@@ -25,7 +21,6 @@
 #include "include/path.h"
 #include "include/policy.h"
 
-
 /* modified from dcache.c */
 static int prepend(char **buffer, int buflen, const char *str, int namelen)
 {
@@ -39,26 +34,65 @@ static int prepend(char **buffer, int buflen, const char *str, int namelen)
 
 #define CHROOT_NSCONNECT (PATH_CHROOT_REL | PATH_CHROOT_NSCONNECT)
 
+/* If the path is not connected to the expected root,
+ * check if it is a sysctl and handle specially else remove any
+ * leading / that __d_path may have returned.
+ * Unless
+ *     specifically directed to connect the path,
+ * OR
+ *     if in a chroot and doing chroot relative paths and the path
+ *     resolves to the namespace root (would be connected outside
+ *     of chroot) and specifically directed to connect paths to
+ *     namespace root.
+ */
+static int disconnect(const struct path *path, char *buf, char **name,
+		      int flags, const char *disconnected)
+{
+	int error = 0;
+
+	if (!(flags & PATH_CONNECT_PATH) &&
+	    !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) &&
+	      our_mnt(path->mnt))) {
+		/* disconnected path, don't return pathname starting
+		 * with '/'
+		 */
+		error = -EACCES;
+		if (**name == '/')
+			*name = *name + 1;
+	} else {
+		if (**name != '/')
+			/* CONNECT_PATH with missing root */
+			error = prepend(name, *name - buf, "/", 1);
+		if (!error && disconnected)
+			error = prepend(name, *name - buf, disconnected,
+					strlen(disconnected));
+	}
+
+	return error;
+}
+
 /**
  * d_namespace_path - lookup a name associated with a given path
  * @path: path to lookup  (NOT NULL)
  * @buf:  buffer to store path to  (NOT NULL)
- * @buflen: length of @buf
  * @name: Returns - pointer for start of path name with in @buf (NOT NULL)
  * @flags: flags controlling path lookup
+ * @disconnected: string to prefix to disconnected paths
  *
  * Handle path name lookup.
  *
  * Returns: %0 else error code if path lookup fails
  *          When no error the path name is returned in @name which points to
- *          to a position in @buf
+ *          a position in @buf
  */
-static int d_namespace_path(struct path *path, char *buf, int buflen,
-			    char **name, int flags)
+static int d_namespace_path(const struct path *path, char *buf, char **name,
+			    int flags, const char *disconnected)
 {
 	char *res;
 	int error = 0;
 	int connected = 1;
+	int isdir = (flags & PATH_IS_DIR) ? 1 : 0;
+	int buflen = aa_g_path_max - isdir;
 
 	if (path->mnt->mnt_flags & MNT_INTERNAL) {
 		/* it's not mounted anywhere */
@@ -73,9 +107,12 @@ static int d_namespace_path(struct path *path, char *buf, int buflen,
 			/* TODO: convert over to using a per namespace
 			 * control instead of hard coded /proc
 			 */
-			return prepend(name, *name - buf, "/proc", 5);
-		}
-		return 0;
+			error = prepend(name, *name - buf, "/proc", 5);
+			goto out;
+		} else
+			error = disconnect(path, buf, name, flags,
+					   disconnected);
+		goto out;
 	}
 
 	/* resolve paths relative to chroot?*/
@@ -93,105 +130,58 @@ static int d_namespace_path(struct path *path, char *buf, int buflen,
 	/* handle error conditions - and still allow a partial path to
 	 * be returned.
 	 */
-	if (!res || IS_ERR(res)) {
-		if (PTR_ERR(res) == -ENAMETOOLONG)
-			return -ENAMETOOLONG;
+	if (IS_ERR_OR_NULL(res)) {
+		if (PTR_ERR(res) == -ENAMETOOLONG) {
+			error = -ENAMETOOLONG;
+			*name = buf;
+			goto out;
+		}
 		connected = 0;
 		res = dentry_path_raw(path->dentry, buf, buflen);
 		if (IS_ERR(res)) {
 			error = PTR_ERR(res);
 			*name = buf;
 			goto out;
-		};
+		}
 	} else if (!our_mnt(path->mnt))
 		connected = 0;
 
 	*name = res;
 
+	if (!connected)
+		error = disconnect(path, buf, name, flags, disconnected);
+
 	/* Handle two cases:
 	 * 1. A deleted dentry && profile is not allowing mediation of deleted
 	 * 2. On some filesystems, newly allocated dentries appear to the
 	 *    security_path hooks as a deleted dentry except without an inode
 	 *    allocated.
 	 */
-	if (d_unlinked(path->dentry) && path->dentry->d_inode &&
-	    !(flags & PATH_MEDIATE_DELETED)) {
+	if (d_unlinked(path->dentry) && d_is_positive(path->dentry) &&
+	    !(flags & (PATH_MEDIATE_DELETED | PATH_DELEGATE_DELETED))) {
 			error = -ENOENT;
 			goto out;
 	}
 
-	/* If the path is not connected to the expected root,
-	 * check if it is a sysctl and handle specially else remove any
-	 * leading / that __d_path may have returned.
-	 * Unless
-	 *     specifically directed to connect the path,
-	 * OR
-	 *     if in a chroot and doing chroot relative paths and the path
-	 *     resolves to the namespace root (would be connected outside
-	 *     of chroot) and specifically directed to connect paths to
-	 *     namespace root.
-	 */
-	if (!connected) {
-		if (!(flags & PATH_CONNECT_PATH) &&
-			   !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) &&
-			     our_mnt(path->mnt))) {
-			/* disconnected path, don't return pathname starting
-			 * with '/'
-			 */
-			error = -EACCES;
-			if (*res == '/')
-				*name = res + 1;
-		}
-	}
-
 out:
-	return error;
-}
-
-/**
- * get_name_to_buffer - get the pathname to a buffer ensure dir / is appended
- * @path: path to get name for  (NOT NULL)
- * @flags: flags controlling path lookup
- * @buffer: buffer to put name in  (NOT NULL)
- * @size: size of buffer
- * @name: Returns - contains position of path name in @buffer (NOT NULL)
- *
- * Returns: %0 else error on failure
- */
-static int get_name_to_buffer(struct path *path, int flags, char *buffer,
-			      int size, char **name, const char **info)
-{
-	int adjust = (flags & PATH_IS_DIR) ? 1 : 0;
-	int error = d_namespace_path(path, buffer, size - adjust, name, flags);
-
-	if (!error && (flags & PATH_IS_DIR) && (*name)[1] != '\0')
-		/*
-		 * Append "/" to the pathname.  The root directory is a special
-		 * case; it already ends in slash.
-		 */
-		strcpy(&buffer[size - 2], "/");
-
-	if (info && error) {
-		if (error == -ENOENT)
-			*info = "Failed name lookup - deleted entry";
-		else if (error == -EACCES)
-			*info = "Failed name lookup - disconnected path";
-		else if (error == -ENAMETOOLONG)
-			*info = "Failed name lookup - name too long";
-		else
-			*info = "Failed name lookup";
-	}
+	/*
+	 * Append "/" to the pathname.  The root directory is a special
+	 * case; it already ends in slash.
+	 */
+	if (!error && isdir && ((*name)[1] != '\0' || (*name)[0] != '/'))
+		strcpy(&buf[aa_g_path_max - 2], "/");
 
 	return error;
 }
 
 /**
- * aa_path_name - compute the pathname of a file
+ * aa_path_name - get the pathname to a buffer ensure dir / is appended
  * @path: path the file  (NOT NULL)
  * @flags: flags controlling path name generation
- * @buffer: buffer that aa_get_name() allocated  (NOT NULL)
+ * @buffer: buffer to put name in (NOT NULL)
  * @name: Returns - the generated path name if !error (NOT NULL)
  * @info: Returns - information on why the path lookup failed (MAYBE NULL)
+ * @disconnected: string to prepend to disconnected paths
  *
  * @name is a pointer to the beginning of the pathname (which usually differs
  * from the beginning of the buffer), or NULL.  If there is an error @name
@@ -204,32 +194,23 @@ static int get_name_to_buffer(struct path *path, int flags, char *buffer,
  *
  * Returns: %0 else error code if could retrieve name
  */
-int aa_path_name(struct path *path, int flags, char **buffer, const char **name,
-		 const char **info)
+int aa_path_name(const struct path *path, int flags, char *buffer,
+		 const char **name, const char **info, const char *disconnected)
 {
-	char *buf, *str = NULL;
-	int size = 256;
-	int error;
-
-	*name = NULL;
-	*buffer = NULL;
-	for (;;) {
-		/* freed by caller */
-		buf = kmalloc(size, GFP_KERNEL);
-		if (!buf)
-			return -ENOMEM;
-
-		error = get_name_to_buffer(path, flags, buf, size, &str, info);
-		if (error != -ENAMETOOLONG)
-			break;
-
-		kfree(buf);
-		size <<= 1;
-		if (size > aa_g_path_max)
-			return -ENAMETOOLONG;
-		*info = NULL;
+	char *str = NULL;
+	int error = d_namespace_path(path, buffer, &str, flags, disconnected);
+
+	if (info && error) {
+		if (error == -ENOENT)
+			*info = "Failed name lookup - deleted entry";
+		else if (error == -EACCES)
+			*info = "Failed name lookup - disconnected path";
+		else if (error == -ENAMETOOLONG)
+			*info = "Failed name lookup - name too long";
+		else
+			*info = "Failed name lookup";
 	}
-	*buffer = buf;
+
 	*name = str;
 
 	return error;