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| author |   Jiri Slaby <jslaby@suse.cz> | 2018-03-22 11:50:26 -0400 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2018-03-22 11:50:26 -0400 |
| commit | fe23cb65c2c394ea306f3714a17d46ab2e6a0af1 (patch) | |
| tree | 2dd4d16379134f12cadd81d8253cef75d2c57265 /fs/ext4 | |
| parent | ext4: update i_disksize if direct write past ondisk size (diff) | |
| download | linux-dev-fe23cb65c2c394ea306f3714a17d46ab2e6a0af1.tar.xz linux-dev-fe23cb65c2c394ea306f3714a17d46ab2e6a0af1.zip | |
ext4: fix offset overflow on 32-bit archs in ext4_iomap_begin()
ext4_iomap_begin() has a bug where offset returned in the iomap
structure will be truncated to unsigned long size. On 64-bit
architectures this is fine but on 32-bit architectures obviously not.
Not many places actually use the offset stored in the iomap structure
but one of visible failures is in SEEK_HOLE / SEEK_DATA implementation.
If we create a file like:
dd if=/dev/urandom of=file bs=1k seek=8m count=1
then
lseek64("file", 0x100000000ULL, SEEK_DATA)
wrongly returns 0x100000000 on unfixed kernel while it should return
0x200000000. Avoid the overflow by proper type cast.
Fixes: 545052e9e35a ("ext4: Switch to iomap for SEEK_HOLE / SEEK_DATA")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org # v4.15
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/inode.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9acac476c15c..d8a692f04156 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3524,7 +3524,7 @@ retry: iomap->flags |= IOMAP_F_DIRTY; iomap->bdev = inode->i_sb->s_bdev; iomap->dax_dev = sbi->s_daxdev; - iomap->offset = first_block << blkbits; + iomap->offset = (u64)first_block << blkbits; iomap->length = (u64)map.m_len << blkbits; if (ret == 0) { |