On Mon, Jun 01, 2020 at 02:49:51PM -0600, Andreas Dilger wrote:
> On Jun 1, 2020, at 2:05 PM, Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> >
> > From: Eric Biggers <ebiggers@xxxxxxxxxx>
> >
> > If the dentry name passed to ->d_compare() fits in dentry::d_iname, then
> > it may be concurrently modified by a rename. This can cause undefined
> > behavior (possibly out-of-bounds memory accesses or crashes) in
> > utf8_strncasecmp(), since fs/unicode/ isn't written to handle strings
> > that may be concurrently modified.
> >
> > Fix this by first copying the filename to a stack buffer if needed.
> > This way we get a stable snapshot of the filename.
> >
> > Fixes: b886ee3e778e ("ext4: Support case-insensitive file name lookups")
> > Cc: <stable@xxxxxxxxxxxxxxx> # v5.2+
> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> > Cc: Daniel Rosenberg <drosen@xxxxxxxxxx>
> > Cc: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxxxx>
> > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
>
> LGTM.
>
> Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
Thanks, applied.
- Ted
