Messages in this thread | | | From | Anton Altaparmakov <> | Subject | Re: [PATCH] ntfs: Fix validity check for file name attribute | Date | Mon, 28 Jun 2021 09:22:53 +0000 |
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Hi,
Thanks for the patch! Have asked Andrew to merge it.
Best regards,
Anton
> On 28 Jun 2021, at 03:45, Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> wrote: > > On 14/6/21 1:05 pm, Desmond Cheong Zhi Xi wrote: >> 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. >> Reported-by: syzbot+213ac8bb98f7f4420840@syzkaller.appspotmail.com >> Tested-by: syzbot+213ac8bb98f7f4420840@syzkaller.appspotmail.com >> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> >> --- >> fs/ntfs/inode.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c >> index f5c058b3192c..4474adb393ca 100644 >> --- a/fs/ntfs/inode.c >> +++ b/fs/ntfs/inode.c >> @@ -477,7 +477,7 @@ static int ntfs_is_extended_system_file(ntfs_attr_search_ctx *ctx) >> } >> 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? */ > > Hi Anton, > > Any chance to review this patch? > > Best wishes, > Desmond
-- Anton Altaparmakov <anton at tuxera.com> (replace at with @) Lead in File System Development, Tuxera Inc., http://www.tuxera.com/ Linux NTFS maintainer
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