shithub: lwext4

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ext4: fix possible access violation when copying name fields

--- a/include/ext4_types.h

+++ b/include/ext4_types.h

@@ -495,8 +495,7 @@

 	uint8_t name_len;   /* Lower 8 bits of name length */

 	union ext4_dir_en_internal in;

-

-	uint8_t name[EXT4_DIRECTORY_FILENAME_LEN]; /* Entry name */

+	uint8_t name[]; /* Entry name */

 };

 /* Structures for indexed directory */

--- a/src/ext4.c

+++ b/src/ext4.c

@@ -2949,6 +2949,7 @@

 #define EXT4_DIR_ENTRY_OFFSET_TERM (uint64_t)(-1)

 	int r;

+	uint16_t name_length;

 	ext4_direntry *de = 0;

 	struct ext4_inode_ref dir;

 	struct ext4_dir_iter it;

@@ -2971,7 +2972,18 @@

 		goto Finish;

 	}

-	memcpy(&d->de, it.curr, sizeof(ext4_direntry));

+	memset(&d->de.name, 0, sizeof(d->de.name));

+	name_length = ext4_dir_en_get_name_len(&d->f.mp->fs.sb,

+					       it.curr);

+	memcpy(&d->de.name, it.curr->name, name_length);

+

+	/* Directly copying the content isn't safe for Big-endian targets*/

+	d->de.inode = ext4_dir_en_get_inode(it.curr);

+	d->de.entry_length = ext4_dir_en_get_entry_len(it.curr);

+	d->de.name_length = name_length;

+	d->de.inode_type = ext4_dir_en_get_inode_type(&d->f.mp->fs.sb,

+						      it.curr);

+

 	de = &d->de;

 	ext4_dir_iterator_next(&it);