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e2fsck: avoid overflow in pass5 check_block_end()

PATCH Applied Eric Sandeen 2 participants 2 messages Sep 1, 2009 – Sep 6, 2009

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Eric Sandeen

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PATCH 1/1 e2fsck: avoid overflow in pass5 check_block_end()

When making a filesystem as in:

mke2fs -E lazy_itable_init=1 -O uninit_bg -b 4096 bigfile 4294967298

a subsequent fsck would result in:

Pass 5: Checking group summary information

Internal error: fudging end of bitmap (3)

e2fsck: aborted

This is because check_block_end() was overflowing in the calculation for "end", and giving it a value of -1 (0xFFFF....) which eventually ended up tripping up a test in ext2fs_fudge_generic_bmap_end,

        if (end > bitmap->real_end)
                return neq;

Fix another such error in read_bitmaps() as well.

lib/ext2fs/imager.c likely has similar problems but it looks like it has no 64-bit treatment at all yet.

Signed-off-by Eric Sandeen <[email protected]>

---

Applies to pu branch.

e2fsck/pass5.c +1 -1
Index: e2fsprogs/e2fsck/pass5.c
===================================================================
@@ -662,7 +662,7 @@ static void check_block_end(e2fsck_t ctx
 	clear_problem_context(&pctx);
 
 	end = ext2fs_get_block_bitmap_start2(fs->block_map) +
-		(EXT2_BLOCKS_PER_GROUP(fs->super) * fs->group_desc_count) - 1;
+		((blk64_t)EXT2_BLOCKS_PER_GROUP(fs->super) * fs->group_desc_count) - 1;
 	pctx.errcode = ext2fs_fudge_block_bitmap_end2(fs->block_map, end,
 						     &save_blocks_count);
 	if (pctx.errcode) {
lib/ext2fs/rw_bitmaps.c +1 -1
Index: e2fsprogs/lib/ext2fs/rw_bitmaps.c
===================================================================
@@ -212,7 +212,7 @@ static errcode_t read_bitmaps(ext2_filsy
 		}
 		blk = (fs->image_header->offset_blockmap /
 		       fs->blocksize);
-		blk_cnt = EXT2_BLOCKS_PER_GROUP(fs->super) *
+		blk_cnt = (blk64_t)EXT2_BLOCKS_PER_GROUP(fs->super) *
 			fs->group_desc_count;
 		while (block_nbytes > 0) {
 			retval = io_channel_read_blk64(fs->image_io, blk++,
Applied
#1 lore raw
Quoted 14 lines · Eric Sandeen

When making a filesystem as in:

mke2fs -E lazy_itable_init=1 -O uninit_bg -b 4096 bigfile 4294967298

a subsequent fsck would result in:

Pass 5: Checking group summary information

Internal error: fudging end of bitmap (3)

e2fsck: aborted

This is because check_block_end() was overflowing in the calculation for "end", and giving it a value of -1 (0xFFFF....) which eventually ended up tripping up a test in ext2fs_fudge_generic_bmap_end,

Quoted 7 lines
        if (end > bitmap->real_end)
                return neq;

Fix another such error in read_bitmaps() as well.

lib/ext2fs/imager.c likely has similar problems but it looks like it has no 64-bit treatment at all yet.

Applied to the e2fsprogs 64-bit patch queue / pu.

- Ted