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ovl: relax WARN_ON in ovl_verify_area() 

syzbot hit an assertion in copy up data loop which looks like it is
the result of a lower file whose size is being changed underneath
overlayfs.

This type of use case is documented to cause undefined behavior, so
returning EIO error for the copy up makes sense, but it should not be
causing a WARN_ON assertion.

Reported-and-tested-by: syzbot+3abd99031b42acf367ef@syzkaller.appspotmail.com
Fixes: ca7ab48240 ("ovl: add permission hooks outside of do_splice_direct()")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
This commit is contained in:
Amir Goldstein 2024-03-17 13:59:43 +02:00
parent 1b17f399a6
commit 77a28aa476
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/overlayfs/copy_up.c
View File

@ -234,11 +234,11 @@ static int ovl_verify_area(loff_t pos, loff_t pos2, loff_t len, loff_t totlen)
{
loff_t tmp;
if (WARN_ON_ONCE(pos != pos2))
if (pos != pos2)
return -EIO;
if (WARN_ON_ONCE(pos < 0 || len < 0 || totlen < 0))
if (pos < 0 || len < 0 || totlen < 0)
return -EIO;
if (WARN_ON_ONCE(check_add_overflow(pos, len, &tmp)))
if (check_add_overflow(pos, len, &tmp))
return -EIO;
return 0;
}