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authorJiri Slaby <jslaby@suse.cz>2018-03-22 16:50:26 +0100
committerTheodore Ts'o <tytso@mit.edu>2018-03-22 16:50:26 +0100
commitfe23cb65c2c394ea306f3714a17d46ab2e6a0af1 (patch)
tree2dd4d16379134f12cadd81d8253cef75d2c57265 /fs/ext4
parentext4: update i_disksize if direct write past ondisk size (diff)
downloadlinux-fe23cb65c2c394ea306f3714a17d46ab2e6a0af1.tar.xz
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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.c2
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) {