On Mon, Feb 24, 2025 at 03:11:03PM +0100, Christoph Hellwig wrote:
> On Thu, Feb 20, 2025 at 02:07:58PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@xxxxxxxxxx>
> >
> > Need to allocate one more byte for the null terminator, just in case the
> > /entire/ input string consists of non-printable bytes e.g. emoji.
> >
> > Cc: <linux-xfs@xxxxxxxxxxxxxxx> # v4.15.0
> > Fixes: 396cd0223598bb ("xfs_scrub: warn about suspicious characters in directory/xattr names")
> > Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
> > ---
> > scrub/common.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/scrub/common.c b/scrub/common.c
> > index 6eb3c026dc5ac9..7ea0277bc511ce 100644
> > --- a/scrub/common.c
> > +++ b/scrub/common.c
> > @@ -320,7 +320,7 @@ string_escape(
> > char *q;
> > int x;
> >
> > - str = malloc(strlen(in) * 4);
> > + str = malloc((strlen(in) * 4) + 1);
>
> Nit: no need for the inner braces.
>
> But this open code string allocation and manipulation makes me feel
> really bad. Assuming we don't have a good alternative, can you
> at least throw in a comment explaining the allocation length here?
Ok. I'll change the code to read as follows:
/*
* Each non-printing byte renders as a four-byte escape sequence, so
* allocate 4x the input length, plus a byte for the null terminator.
*/
str = malloc(strlen(in) * 4 + 1);
--D
