cifs: refactor and clean up arguments in the reparse point parsing

Will be helpful as we improve handling of special file types.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 31 insertions, 35 deletions

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index c4047ad7b43f..4b0b14946343 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2383,11 +2383,6 @@ parse_reparse_posix(struct reparse_posix_data *symlink_buf,
         /* See MS-FSCC 2.1.2.6 for the 'NFS' style reparse tags */
         len = le16_to_cpu(symlink_buf->ReparseDataLength);
 
-        if (len + sizeof(struct reparse_data_buffer) > plen) {
-                cifs_dbg(VFS, "srv returned malformed symlink buffer\n");
-                return -EINVAL;
-        }
-
         if (le64_to_cpu(symlink_buf->InodeType) != NFS_SPECFILE_LNK) {
                 cifs_dbg(VFS, "%lld not a supported symlink type\n",
                         le64_to_cpu(symlink_buf->InodeType));
@@ -2437,22 +2432,38 @@ parse_reparse_symlink(struct reparse_symlink_data_buffer *symlink_buf,
 }
 
 static int
-parse_reparse_point(struct reparse_symlink_data_buffer *buf,
-                      u32 plen, char **target_path,
-                      struct cifs_sb_info *cifs_sb)
+parse_reparse_point(struct reparse_data_buffer *buf,
+                    u32 plen, char **target_path,
+                    struct cifs_sb_info *cifs_sb)
 {
-        /* See MS-FSCC 2.1.2 */
-        if (le32_to_cpu(buf->ReparseTag) == IO_REPARSE_TAG_NFS)
-                return parse_reparse_posix((struct reparse_posix_data *)buf,
-                        plen, target_path, cifs_sb);
-        else if (le32_to_cpu(buf->ReparseTag) == IO_REPARSE_TAG_SYMLINK)
-                return parse_reparse_symlink(buf, plen, target_path,
-                                        cifs_sb);
+        if (plen < sizeof(struct reparse_data_buffer)) {
+                cifs_dbg(VFS, "reparse buffer is too small. Must be "
+                         "at least 8 bytes but was %d\n", plen);
+                return -EIO;
+        }
 
-        cifs_dbg(VFS, "srv returned invalid symlink buffer tag:%d\n",
-                le32_to_cpu(buf->ReparseTag));
+        if (plen < le16_to_cpu(buf->ReparseDataLength) +
+            sizeof(struct reparse_data_buffer)) {
+                cifs_dbg(VFS, "srv returned invalid reparse buf "
+                         "length: %d\n", plen);
+                return -EIO;
+        }
 
-        return -EIO;
+        /* See MS-FSCC 2.1.2 */
+        switch (le32_to_cpu(buf->ReparseTag)) {
+        case IO_REPARSE_TAG_NFS:
+                return parse_reparse_posix(
+                        (struct reparse_posix_data *)buf,
+                        plen, target_path, cifs_sb);
+        case IO_REPARSE_TAG_SYMLINK:
+                return parse_reparse_symlink(
+                        (struct reparse_symlink_data_buffer *)buf,
+                        plen, target_path, cifs_sb);
+        default:
+                cifs_dbg(VFS, "srv returned unknown symlink buffer "
+                         "tag:0x%08x\n", le32_to_cpu(buf->ReparseTag));
+                return -EOPNOTSUPP;
+        }
 }
 
 #define SMB2_SYMLINK_STRUCT_SIZE \
@@ -2581,23 +2592,8 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
                         goto querty_exit;
                 }
 
-                if (plen < 8) {
-                        cifs_dbg(VFS, "reparse buffer is too small. Must be "
-                                 "at least 8 bytes but was %d\n", plen);
-                        rc = -EIO;
-                        goto querty_exit;
-                }
-
-                if (plen < le16_to_cpu(reparse_buf->ReparseDataLength) + 8) {
-                        cifs_dbg(VFS, "srv returned invalid reparse buf "
-                                 "length: %d\n", plen);
-                        rc = -EIO;
-                        goto querty_exit;
-                }
-
-                rc = parse_reparse_point(
-                        (struct reparse_symlink_data_buffer *)reparse_buf,
-                        plen, target_path, cifs_sb);
+                rc = parse_reparse_point(reparse_buf, plen, target_path,
+                                         cifs_sb);
                 goto querty_exit;
         }