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| author | Edward Adam Davis <eadavis@qq.com> | 2026-02-23 11:01:13 +0300 |
|---|---|---|
| committer | Konstantin Komarov <almaz.alexandrovich@paragon-software.com> | 2026-03-04 12:28:42 +0300 |
| commit | e98266e823a1fa06fe6499df61aeaac2fd6f7a49 (patch) | |
| tree | 400aef8acf7116cf68d3da8d0982f9b76e54d1e6 | |
| parent | 48d9b57b169fb39d7362034a32706453d107ed6e (diff) | |
| download | linux-e98266e823a1fa06fe6499df61aeaac2fd6f7a49.tar.xz | |
fs/ntfs3: prevent uninitialized lcn caused by zero len
syzbot reported a uninit-value in ntfs_iomap_begin [1].
Since runs was not touched yet, run_lookup_entry() immediately fails
and returns false, which makes the value of "*len" 0.
Simultaneously, the new value and err value are also 0, causing the
logic in attr_data_get_block_locked() to jump directly to ok, ultimately
resulting in *lcn being triggered before it is set [1].
In ntfs_iomap_begin(), the check for a 0 value in clen is moved forward
to before updating lcn to avoid this [1].
[1]
BUG: KMSAN: uninit-value in ntfs_iomap_begin+0x8c0/0x1460 fs/ntfs3/inode.c:825
ntfs_iomap_begin+0x8c0/0x1460 fs/ntfs3/inode.c:825
iomap_iter+0x9b7/0x1540 fs/iomap/iter.c:110
Local variable lcn created at:
ntfs_iomap_begin+0x15d/0x1460 fs/ntfs3/inode.c:786
Fixes: 10d7c95af043 ("fs/ntfs3: add delayed-allocation (delalloc) support")
Reported-by: syzbot+7be88937363ac7ab7bb0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7be88937363ac7ab7bb0
Tested-by: syzbot+7be88937363ac7ab7bb0@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
| -rw-r--r-- | fs/ntfs3/inode.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c index 398913595a55..733d4c86edba 100644 --- a/fs/ntfs3/inode.c +++ b/fs/ntfs3/inode.c @@ -827,6 +827,11 @@ static int ntfs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, return err; } + if (!clen) { + /* broken file? */ + return -EINVAL; + } + if (lcn == EOF_LCN) { /* request out of file. */ if (flags & IOMAP_REPORT) { @@ -860,11 +865,6 @@ static int ntfs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, return 0; } - if (!clen) { - /* broken file? */ - return -EINVAL; - } - iomap->bdev = inode->i_sb->s_bdev; iomap->offset = offset; iomap->length = ((loff_t)clen << cluster_bits) - off; |