From: Karel Zak <kzak@redhat.com>
Date: Thu, 14 Jun 2012 12:19:26 +0000 (+0200)
Subject: libmount: don't use nosuid,noexec,nodev for cifs user=foo
X-Git-Tag: v2.22-rc1~287
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e90e7401d0c318c9dac4a0204e2bca86949b1d32;p=thirdparty%2Futil-linux.git

libmount: don't use nosuid,noexec,nodev for cifs user=foo

   mount -t cifs //127.0.0.1/users /mnt/smb -o user=root,password=linux

is incorrectly translated to

   mount.cifs -o noexec,nosuid,nodev,user=root,password=linux ...

The command mount(8) should be sensitive to "user" (without "=<name>")
only. The correct cifs command line is:

   mount.cifs -o user=root,password=linux

Addresses: https://bugzilla.novell.com/show_bug.cgi?id=766157
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libmount/src/context_mount.c b/libmount/src/context_mount.c
index 6661394ffc..69b5bfc13d 100644
--- a/libmount/src/context_mount.c
+++ b/libmount/src/context_mount.c
@@ -53,6 +53,15 @@ static int fix_optstr(struct libmnt_context *cxt)
 	if (cxt->mountflags & MS_PROPAGATION)
 		cxt->mountflags &= (MS_PROPAGATION | MS_REC | MS_SILENT);
 
+	/*
+	 * The "user" options is our business (so we can modify the option),
+	 * but exception is command line for /sbin/mount.<type> helpers. Let's
+	 * save the original user=<name> to call the helpers with unchanged
+	 * "user" setting.
+	 *
+	 * Don't check for MNT_MS_USER in cxt->user_mountflags, the flag maybe
+	 * removed by evaluate_permissions().
+	 */
 	if (!mnt_optstr_get_option(fs->user_optstr, "user", &val, &valsz)) {
 		if (val) {
 			cxt->orig_user = strndup(val, valsz);
@@ -210,6 +219,10 @@ err:
 
 /*
  * this has to be called before fix_optstr()
+ *
+ * Note that user=<name> maybe be used by some filesystems as filesystem
+ * specific option (e.g. cifs). Yes, developers of such filesystems have
+ * allocated pretty hot place in hell...
  */
 static int evaluate_permissions(struct libmnt_context *cxt)
 {
@@ -247,10 +260,22 @@ static int evaluate_permissions(struct libmnt_context *cxt)
 		}
 
 		/*
-		 * Note that MS_OWNERSECURE and MS_SECURE mount options
-		 * are applied by mnt_optstr_get_flags() from mnt_context_merge_mflags()
+		 * MS_OWNERSECURE and MS_SECURE mount options are already
+		 * applied by mnt_optstr_get_flags() in mnt_context_merge_mflags()
+		 * if "user" (but no user=<name> !) options is set.
+		 *
+		 * Let's ignore all user=<name> (if <name> is set) requests.
 		 */
+		if (cxt->user_mountflags & MNT_MS_USER) {
+			size_t valsz = 0;
 
+			if (!mnt_optstr_get_option(cxt->fs->user_optstr,
+					"user", NULL, &valsz) && valsz) {
+
+				DBG(CXT, mnt_debug_h(cxt, "perms: user=<name> detected, ignore"));
+				cxt->user_mountflags &= ~MNT_MS_USER;
+			}
+		}
 
 		/*
 		 * MS_OWNER: Allow owners to mount when fstab contains the
diff --git a/libmount/src/optstr.c b/libmount/src/optstr.c
index ca1b2e2c7f..c8beadad2a 100644
--- a/libmount/src/optstr.c
+++ b/libmount/src/optstr.c
@@ -586,7 +586,7 @@ int mnt_optstr_get_flags(const char *optstr, unsigned long *flags,
 {
 	struct libmnt_optmap const *maps[2];
 	char *name, *str = (char *) optstr;
-	size_t namesz = 0;
+	size_t namesz = 0, valsz = 0;
 	int nmaps = 0;
 
 	assert(optstr);
@@ -603,7 +603,7 @@ int mnt_optstr_get_flags(const char *optstr, unsigned long *flags,
 		 */
 		maps[nmaps++] = mnt_get_builtin_optmap(MNT_USERSPACE_MAP);
 
-	while(!mnt_optstr_next_option(&str, &name, &namesz, NULL, NULL)) {
+	while(!mnt_optstr_next_option(&str, &name, &namesz, NULL, &valsz)) {
 		const struct libmnt_optmap *ent;
 		const struct libmnt_optmap *m;
 
@@ -617,9 +617,10 @@ int mnt_optstr_get_flags(const char *optstr, unsigned long *flags,
 			else
 				*flags |= ent->id;
 
-		} else if (nmaps == 2 && m == maps[1]) {
+		} else if (nmaps == 2 && m == maps[1] && valsz == 0) {
 			/*
-			 * Special case -- translate "user" to MS_ options
+			 * Special case -- translate "user" (but no user=) to
+			 * MS_ options
 			 */
 			if (ent->mask & MNT_INVERT)
 				continue;