fat: use fat_fs_error() instead of BUG_ON() in __fat_get_block()

If file size and FAT cluster chain is not matched (corrupted image), we can hit BUG_ON(!phys) in __fat_get_block(). So, use fat_fs_error() instead. [[email protected]: fix printk warning] Link: http://lkml.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: OGAWA Hirofumi <[email protected]> Reported-by: Anatoly Trosinenko <[email protected]> Tested-by: Anatoly Trosinenko <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
strager · Jun 14, 2018 · c2574aa · c2574aa
1 parent 26b9513
commit c2574aa
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
@@ -158,8 +158,14 @@ static inline int __fat_get_block(struct inode *inode, sector_t iblock,
 	err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
 	if (err)
 		return err;
+	if (!phys) {
+		fat_fs_error(sb,
+			     "invalid FAT chain (i_pos %lld, last_block %llu)",
+			     MSDOS_I(inode)->i_pos,
+			     (unsigned long long)last_block);
+		return -EIO;
+	}
 
-	BUG_ON(!phys);
 	BUG_ON(*max_blocks != mapped_blocks);
 	set_buffer_new(bh_result);
 	map_bh(bh_result, sb, phys);