From 63362e153f799f41d3e0dd256d8b8281da3f2672 Mon Sep 17 00:00:00 2001 From: Jin Qian Date: Fri, 24 Mar 2017 17:01:54 -0700 Subject: [PATCH] ext4_utils: fix crash when filesystem size is too small make_ext4fs crashes if size is less than block size or less than header size (super block + descriptors + bitmaps). Check the size and return errors. Test: run make_ext4fs with small sizes Bug: 36576677 Change-Id: I61d92e280cdf290054fadda5a045fc839c6fd8fe --- ext4_utils/ext4_utils.c | 3 +++ ext4_utils/make_ext4fs.c | 10 +++++----- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/ext4_utils/ext4_utils.c b/ext4_utils/ext4_utils.c index 550181f3..07a92119 100644 --- a/ext4_utils/ext4_utils.c +++ b/ext4_utils/ext4_utils.c @@ -222,6 +222,9 @@ void ext4_create_fs_aux_info() if (ext4_bg_has_super_block(aux_info.groups - 1)) last_header_size += 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks; + if (aux_info.groups <= 1 && last_group_size < last_header_size) { + critical_error("filesystem size too small"); + } if (last_group_size > 0 && last_group_size < last_header_size) { aux_info.groups--; aux_info.len_blocks -= last_group_size; diff --git a/ext4_utils/make_ext4fs.c b/ext4_utils/make_ext4fs.c index b84db9b3..58069f31 100644 --- a/ext4_utils/make_ext4fs.c +++ b/ext4_utils/make_ext4fs.c @@ -753,17 +753,17 @@ int make_ext4fs_internal(int fd, const char *_directory, const char *_target_out if (info.len <= 0) info.len = get_file_size(fd); - if (info.len <= 0) { - fprintf(stderr, "Need size of filesystem\n"); - return EXIT_FAILURE; - } - if (info.block_size <= 0) info.block_size = compute_block_size(); /* Round down the filesystem length to be a multiple of the block size */ info.len &= ~((u64)info.block_size - 1); + if (info.len <= 0) { + fprintf(stderr, "filesystem size too small\n"); + return EXIT_FAILURE; + } + if (info.journal_blocks == 0) info.journal_blocks = compute_journal_blocks(); -- 2.11.0