1 files changed, 25 insertions, 20 deletions

diff --git a/drivers/staging/erofs/dir.c b/drivers/staging/erofs/dir.c
index 829f7b12e0dc..9bbc68729c11 100644
--- a/drivers/staging/erofs/dir.c
+++ b/drivers/staging/erofs/dir.c
@@ -23,6 +23,21 @@ static const unsigned char erofs_filetype_table[EROFS_FT_MAX] = {
         [EROFS_FT_SYMLINK]      = DT_LNK,
 };
 
+static void debug_one_dentry(unsigned char d_type, const char *de_name,
+                             unsigned int de_namelen)
+{
+#ifdef CONFIG_EROFS_FS_DEBUG
+        /* since the on-disk name could not have the trailing '\0' */
+        unsigned char dbg_namebuf[EROFS_NAME_LEN + 1];
+
+        memcpy(dbg_namebuf, de_name, de_namelen);
+        dbg_namebuf[de_namelen] = '\0';
+
+        debugln("found dirent %s de_len %u d_type %d", dbg_namebuf,
+                de_namelen, d_type);
+#endif
+}
+
 static int erofs_fill_dentries(struct dir_context *ctx,
                                void *dentry_blk, unsigned int *ofs,
                                unsigned int nameoff, unsigned int maxsize)
@@ -33,14 +48,10 @@ static int erofs_fill_dentries(struct dir_context *ctx,
         de = dentry_blk + *ofs;
         while (de < end) {
                 const char *de_name;
-                int de_namelen;
+                unsigned int de_namelen;
                 unsigned char d_type;
-#ifdef CONFIG_EROFS_FS_DEBUG
-                unsigned int dbg_namelen;
-                unsigned char dbg_namebuf[EROFS_NAME_LEN];
-#endif
 
-                if (unlikely(de->file_type < EROFS_FT_MAX))
+                if (de->file_type < EROFS_FT_MAX)
                         d_type = erofs_filetype_table[de->file_type];
                 else
                         d_type = DT_UNKNOWN;
@@ -48,26 +59,20 @@ static int erofs_fill_dentries(struct dir_context *ctx,
                 nameoff = le16_to_cpu(de->nameoff);
                 de_name = (char *)dentry_blk + nameoff;
 
-                de_namelen = unlikely(de + 1 >= end) ?
-                        /* last directory entry */
-                        strnlen(de_name, maxsize - nameoff) :
-                        le16_to_cpu(de[1].nameoff) - nameoff;
+                /* the last dirent in the block? */
+                if (de + 1 >= end)
+                        de_namelen = strnlen(de_name, maxsize - nameoff);
+                else
+                        de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
 
                 /* a corrupted entry is found */
-                if (unlikely(de_namelen < 0)) {
+                if (unlikely(nameoff + de_namelen > maxsize ||
+                             de_namelen > EROFS_NAME_LEN)) {
                         DBG_BUGON(1);
                         return -EIO;
                 }
 
-#ifdef CONFIG_EROFS_FS_DEBUG
-                dbg_namelen = min(EROFS_NAME_LEN - 1, de_namelen);
-                memcpy(dbg_namebuf, de_name, dbg_namelen);
-                dbg_namebuf[dbg_namelen] = '\0';
-
-                debugln("%s, found de_name %s de_len %d d_type %d", __func__,
-                        dbg_namebuf, de_namelen, d_type);
-#endif
-
+                debug_one_dentry(d_type, de_name, de_namelen);
                 if (!dir_emit(ctx, de_name, de_namelen,
                               le64_to_cpu(de->nid), d_type))
                         /* stopped by some reason */