The patch titled
Subject: ntfs: fix validity check for file name attribute
has been added to the -mm tree. Its filename is
ntfs-fix-validity-check-for-file-name-attribute.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/ntfs-fix-validity-check-for-file-name-attribute.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/ntfs-fix-validity-check-for-file-name-attribute.patch
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------------------------------------------------------
From: Desmond Cheong Zhi Xi <desmondcheongzx@xxxxxxxxx>
Subject: ntfs: fix validity check for file name attribute
When checking the file name attribute, we want to ensure that it fits
within the bounds of ATTR_RECORD. To do this, we should check that (attr
record + file name offset + file name length) < (attr record + attr record
length).
However, the original check did not include the file name offset in the
calculation. This means that corrupted on-disk metadata might not caught
by the incorrect file name check, and lead to an invalid memory access.
An example can be seen in the crash report of a memory corruption error
found by Syzbot:
https://syzkaller.appspot.com/bug?id=a1a1e379b225812688566745c3e2f7242bffc246
Adding the file name offset to the validity check fixes this error and
passes the Syzbot reproducer test.
Link: https://lkml.kernel.org/r/20210614050540.289494-1-desmondcheongzx@xxxxxxxxx
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@xxxxxxxxx>
Reported-by: syzbot+213ac8bb98f7f4420840@xxxxxxxxxxxxxxxxxxxxxxxxx
Tested-by: syzbot+213ac8bb98f7f4420840@xxxxxxxxxxxxxxxxxxxxxxxxx
Acked-by: Anton Altaparmakov <anton@xxxxxxxxxx>
Cc: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ntfs/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ntfs/inode.c~ntfs-fix-validity-check-for-file-name-attribute
+++ a/fs/ntfs/inode.c
@@ -477,7 +477,7 @@ err_corrupt_attr:
}
file_name_attr = (FILE_NAME_ATTR*)((u8*)attr +
le16_to_cpu(attr->data.resident.value_offset));
- p2 = (u8*)attr + le32_to_cpu(attr->data.resident.value_length);
+ p2 = (u8 *)file_name_attr + le32_to_cpu(attr->data.resident.value_length);
if (p2 < (u8*)attr || p2 > p)
goto err_corrupt_attr;
/* This attribute is ok, but is it in the $Extend directory? */
_
Patches currently in -mm which might be from desmondcheongzx@xxxxxxxxx are
ntfs-fix-validity-check-for-file-name-attribute.patch
