Re: [Cluster-devel] [PATCH] gfs2: move from strlcpy with unused retval to strscpy

From: Wolfram Sang
Date: Wed Aug 24 2022 - 16:08:46 EST


Hi Andy.

> > - strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> > - strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> > + strscpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> > + strscpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
>
> Perhaps the size should be changed to GFS2_LOCKNAME_LEN to match the size of
> the destination, too.
>
> With that addition, this patch fixes this syzkaller report:
>
> https://listman.redhat.com/archives/cluster-devel/2022-August/022755.html

Linus wrote another summary about strlcpy vs. strscpy use[1]. So, the
size argument should be the size of the smaller buffer if the buffers
are of different size. GFS2_LOCKNAME_LEN is smaller, so that looks
suitable. Shall I resend the patch with the suggested change?

All the best,

Wolfram

[1] https://lore.kernel.org/lkml/CAHk-=wi+xbVq++uqW9YgWpHjyBHNB8a-xad+Xp23-B+eodLCEA@xxxxxxxxxxxxxx/

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