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Date: Sat, 26 Jul 2014 09:48:33 -0400
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Theodore Ts'o <tytso@....edu>
Subject: [PATCH 5/6] Fix 32/64-bit overflow when multiplying by blocks/clusters per group
There are a number of places where we need convert groups to blocks or
clusters by multiply the groups by blocks/clusters per group.
Unfortunately, both quantities are 32-bit, but the result needs to be
64-bit, and very often the cast to 64-bit gets lost.
Fix this by adding new macros, EXT2_GROUPS_TO_BLOCKS() and
EXT2_GROUPS_TO_CLUSTERS().
This should fix a bug where resizing a 64bit file system can result in
calculate_minimum_resize_size() looping forever.
Addresses-Launchpad-Bug: #1321958
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
e2fsck/pass5.c | 2 +-
e2fsck/super.c | 2 +-
lib/ext2fs/blknum.c | 2 +-
lib/ext2fs/ext2_fs.h | 5 +++++
lib/ext2fs/imager.c | 14 +++++++-------
lib/ext2fs/rw_bitmaps.c | 4 ++--
misc/tune2fs.c | 2 +-
resize/resize2fs.c | 11 +++++------
8 files changed, 23 insertions(+), 19 deletions(-)
diff --git a/e2fsck/pass5.c b/e2fsck/pass5.c
index d0b1ced..bc9a32a 100644
--- a/e2fsck/pass5.c
+++ b/e2fsck/pass5.c
@@ -776,7 +776,7 @@ static void check_block_end(e2fsck_t ctx)
clear_problem_context(&pctx);
end = ext2fs_get_block_bitmap_start2(fs->block_map) +
- ((blk64_t)EXT2_CLUSTERS_PER_GROUP(fs->super) * fs->group_desc_count) - 1;
+ EXT2_GROUPS_TO_CLUSTERS(fs->super, fs->group_desc_count) - 1;
pctx.errcode = ext2fs_fudge_block_bitmap_end2(fs->block_map, end,
&save_blocks_count);
if (pctx.errcode) {
diff --git a/e2fsck/super.c b/e2fsck/super.c
index 81503d4..8d468e6 100644
--- a/e2fsck/super.c
+++ b/e2fsck/super.c
@@ -421,7 +421,7 @@ void check_resize_inode(e2fsck_t ctx)
for (j = 1; j < fs->group_desc_count; j++) {
if (!ext2fs_bg_has_super(fs, j))
continue;
- expect = pblk + (j * fs->super->s_blocks_per_group);
+ expect = pblk + EXT2_GROUPS_TO_BLOCKS(fs->super, j);
if (ind_buf[ind_off] != expect)
goto resize_inode_invalid;
ind_off++;
diff --git a/lib/ext2fs/blknum.c b/lib/ext2fs/blknum.c
index 8ced1ee..7ce6053 100644
--- a/lib/ext2fs/blknum.c
+++ b/lib/ext2fs/blknum.c
@@ -29,7 +29,7 @@ dgrp_t ext2fs_group_of_blk2(ext2_filsys fs, blk64_t blk)
blk64_t ext2fs_group_first_block2(ext2_filsys fs, dgrp_t group)
{
return fs->super->s_first_data_block +
- ((blk64_t)group * fs->super->s_blocks_per_group);
+ EXT2_GROUPS_TO_BLOCKS(fs->super, group);
}
/*
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index d9e14d7..6c3620c 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -264,6 +264,11 @@ struct ext2_dx_countlimit {
#define EXT2_DESC_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / EXT2_DESC_SIZE(s))
#endif
+#define EXT2_GROUPS_TO_BLOCKS(s, g) ((blk64_t) EXT2_BLOCKS_PER_GROUP(s) * \
+ (g))
+#define EXT2_GROUPS_TO_CLUSTERS(s, g) ((blk64_t) EXT2_CLUSTERS_PER_GROUP(s) * \
+ (g))
+
/*
* Constants relative to the data blocks
*/
diff --git a/lib/ext2fs/imager.c b/lib/ext2fs/imager.c
index 378a3c8..b643cc6 100644
--- a/lib/ext2fs/imager.c
+++ b/lib/ext2fs/imager.c
@@ -286,8 +286,8 @@ errcode_t ext2fs_image_bitmap_write(ext2_filsys fs, int fd, int flags)
ext2fs_generic_bitmap bmap;
errcode_t retval;
ssize_t actual;
- __u32 itr, cnt, size;
- int c, total_size;
+ size_t c;
+ __u64 itr, cnt, size, total_size;
char buf[1024];
if (flags & IMAGER_FLAG_INODEMAP) {
@@ -308,7 +308,7 @@ errcode_t ext2fs_image_bitmap_write(ext2_filsys fs, int fd, int flags)
}
bmap = fs->block_map;
itr = fs->super->s_first_data_block;
- cnt = EXT2_BLOCKS_PER_GROUP(fs->super) * fs->group_desc_count;
+ cnt = EXT2_GROUPS_TO_BLOCKS(fs->super, fs->group_desc_count);
size = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
}
total_size = size * fs->group_desc_count;
@@ -342,9 +342,9 @@ errcode_t ext2fs_image_bitmap_write(ext2_filsys fs, int fd, int flags)
if (c > (int) sizeof(buf))
c = sizeof(buf);
actual = write(fd, buf, c);
- if (actual == -1)
+ if (actual < 0)
return errno;
- if (actual != c)
+ if ((size_t) actual != c)
return EXT2_ET_SHORT_WRITE;
size -= c;
}
@@ -360,7 +360,7 @@ errcode_t ext2fs_image_bitmap_read(ext2_filsys fs, int fd, int flags)
{
ext2fs_generic_bitmap bmap;
errcode_t retval;
- __u32 itr, cnt;
+ __u64 itr, cnt;
char buf[1024];
unsigned int size;
ssize_t actual;
@@ -383,7 +383,7 @@ errcode_t ext2fs_image_bitmap_read(ext2_filsys fs, int fd, int flags)
}
bmap = fs->block_map;
itr = fs->super->s_first_data_block;
- cnt = EXT2_BLOCKS_PER_GROUP(fs->super) * fs->group_desc_count;
+ cnt = EXT2_GROUPS_TO_BLOCKS(fs->super, fs->group_desc_count);
size = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
}
diff --git a/lib/ext2fs/rw_bitmaps.c b/lib/ext2fs/rw_bitmaps.c
index d24ba9a..a07ecd5 100644
--- a/lib/ext2fs/rw_bitmaps.c
+++ b/lib/ext2fs/rw_bitmaps.c
@@ -262,8 +262,8 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
}
blk = (fs->image_header->offset_blockmap /
fs->blocksize);
- blk_cnt = (blk64_t)EXT2_CLUSTERS_PER_GROUP(fs->super) *
- fs->group_desc_count;
+ blk_cnt = EXT2_GROUPS_TO_CLUSTERS(fs->super,
+ fs->group_desc_count);
while (block_nbytes > 0) {
retval = io_channel_read_blk64(fs->image_io, blk++,
1, block_bitmap);
diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index 6b21235..ad0b05f 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -1383,7 +1383,7 @@ static int ext2fs_is_block_in_group(ext2_filsys fs, dgrp_t group, blk64_t blk)
{
blk64_t start_blk, end_blk;
start_blk = fs->super->s_first_data_block +
- EXT2_BLOCKS_PER_GROUP(fs->super) * group;
+ EXT2_GROUPS_TO_BLOCKS(fs->super, group);
/*
* We cannot get new block beyond end_blk for for the last block group
* so we can check with EXT2_BLOCKS_PER_GROUP even for last block group
diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index 6bd2e1c..9641b1e 100644
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -436,8 +436,7 @@ retry:
fs->inode_map);
if (retval) goto errout;
- real_end = (((blk64_t) EXT2_BLOCKS_PER_GROUP(fs->super) *
- fs->group_desc_count)) - 1 +
+ real_end = EXT2_GROUPS_TO_BLOCKS(fs->super, fs->group_desc_count) - 1 +
fs->super->s_first_data_block;
retval = ext2fs_resize_block_bitmap2(new_size - 1,
real_end, fs->block_map);
@@ -2318,7 +2317,7 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
fs->super->s_free_inodes_count;
blks_needed = ext2fs_div_ceil(inode_count,
fs->super->s_inodes_per_group) *
- EXT2_BLOCKS_PER_GROUP(fs->super);
+ (blk64_t) EXT2_BLOCKS_PER_GROUP(fs->super);
groups = ext2fs_div64_ceil(blks_needed,
EXT2_BLOCKS_PER_GROUP(fs->super));
#ifdef RESIZE2FS_DEBUG
@@ -2365,7 +2364,7 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
* figure out how many data blocks we have given the number of groups
* we need for our inodes
*/
- data_blocks = groups * EXT2_BLOCKS_PER_GROUP(fs->super);
+ data_blocks = EXT2_GROUPS_TO_BLOCKS(fs->super, groups);
last_start = 0;
for (grp = 0; grp < flex_groups; grp++) {
overhead = calc_group_overhead(fs, grp, old_desc_blocks);
@@ -2403,7 +2402,7 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
extra_grps = ext2fs_div64_ceil(remainder,
EXT2_BLOCKS_PER_GROUP(fs->super));
- data_blocks += extra_grps * EXT2_BLOCKS_PER_GROUP(fs->super);
+ data_blocks += EXT2_GROUPS_TO_BLOCKS(fs->super, extra_grps);
/* ok we have to account for the last group */
overhead = calc_group_overhead(fs, groups-1, old_desc_blocks);
@@ -2501,7 +2500,7 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
* blocks needed to handle the group descriptor metadata+data
* that we need
*/
- blks_needed = (groups-1) * EXT2_BLOCKS_PER_GROUP(fs->super);
+ blks_needed = EXT2_GROUPS_TO_BLOCKS(fs->super, groups - 1);
blks_needed += overhead;
/*
--
2.0.0
--
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