iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ext4: add sanity checking to count_overhead()

Browse Source 
commit c48ae41bafe31e9a66d8be2ced4e42a6b57fa814 upstream.

The commit "ext4: sanity check the block and cluster size at mount
time" should prevent any problems, but in case the superblock is
modified while the file system is mounted, add an extra safety check
to make sure we won't overrun the allocated buffer.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Theodore Ts'o 2016-11-18 13:37:47 -05:00 committed by Greg Kroah-Hartman
parent 3995881b0f
commit f655b3575c
1 changed files with 8 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
fs/ext4/super.c
View File

@ -3037,10 +3037,15 @@ static int count_overhead(struct super_block *sb, ext4_group_t grp,
ext4_set_bit(s++, buf);
count++;
}
for (j = ext4_bg_num_gdb(sb, grp); j > 0; j--) {
ext4_set_bit(EXT4_B2C(sbi, s++), buf);
count++;
j = ext4_bg_num_gdb(sb, grp);
if (s + j > EXT4_BLOCKS_PER_GROUP(sb)) {
ext4_error(sb, "Invalid number of block group "
"descriptor blocks: %d", j);
j = EXT4_BLOCKS_PER_GROUP(sb) - s;
}
count += j;
for (; j > 0; j--)
ext4_set_bit(EXT4_B2C(sbi, s++), buf);
}
if (!count)
return 0;