cifs: sanitize paths in cifs_update_super_prepath.

After a server reboot, clients are failing to move files with ENOENT.
This is caused by DFS referrals containing multiple separators, which
the server move call doesn't recognize.

v1: Initial patch.
v2: Move prototype to header.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2182472
Fixes: a31080899d5f ("cifs: sanitize multiple delimiters in prepath")
Actually-Fixes: 24e0a1eff9e2 ("cifs: switch to new mount api")
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Thiago Rafael Becker <tbecker@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index 6d13f8207e96a146a44860538cfaf1045924b4b2..ace11a1a7c8abc07e9df9ec7e9fbf2bd61455e1c 100644 (file)
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -441,13 +441,14 @@ out:
  * but there are some bugs that prevent rename from working if there are
  * multiple delimiters.
  *
- * Returns a sanitized duplicate of @path. The caller is responsible for
- * cleaning up the original.
+ * Returns a sanitized duplicate of @path. @gfp indicates the GFP_* flags
+ * for kstrdup.
+ * The caller is responsible for freeing the original.
  */
 #define IS_DELIM(c) ((c) == '/' || (c) == '\\')
-static char *sanitize_path(char *path)
+char *cifs_sanitize_prepath(char *prepath, gfp_t gfp)
 {
-       char *cursor1 = path, *cursor2 = path;
+       char *cursor1 = prepath, *cursor2 = prepath;
 
        /* skip all prepended delimiters */
        while (IS_DELIM(*cursor1))
@@ -469,7 +470,7 @@ static char *sanitize_path(char *path)
                cursor2--;
 
        *(cursor2) = '\0';
-       return kstrdup(path, GFP_KERNEL);
+       return kstrdup(prepath, gfp);
 }
 
 /*
@@ -531,7 +532,7 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
        if (!*pos)
                return 0;
 
-       ctx->prepath = sanitize_path(pos);
+       ctx->prepath = cifs_sanitize_prepath(pos, GFP_KERNEL);
        if (!ctx->prepath)
                return -ENOMEM;
 

diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index 3de00e7127ec49624918aaff189544ebe99ecd87..f4eaf855890222924c99a92f693f131b0c69cde7 100644 (file)
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -287,4 +287,7 @@ extern void smb3_update_mnt_flags(struct cifs_sb_info *cifs_sb);
  */
 #define SMB3_MAX_DCLOSETIMEO (1 << 30)
 #define SMB3_DEF_DCLOSETIMEO (1 * HZ) /* even 1 sec enough to help eg open/write/close/open/read */
+
+extern char *cifs_sanitize_prepath(char *prepath, gfp_t gfp);
+
 #endif

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index eea8defff43149cf6e5363fff2d3066d3fd634d9..2f3f27b772232a6062f705dd68cd29d44315a3f1 100644 (file)
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -1298,7 +1298,7 @@ int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
        kfree(cifs_sb->prepath);
 
        if (prefix && *prefix) {
-               cifs_sb->prepath = kstrdup(prefix, GFP_ATOMIC);
+               cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
                if (!cifs_sb->prepath)
                        return -ENOMEM;