linux-kernel - Re: [syzbot] [crypto?] general protection fault in shash_async

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZIrWOe4pG7M3TJic@gondor.apana.org.au>
Date:   Thu, 15 Jun 2023 17:13:29 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     David Howells <dhowells@...hat.com>
Cc:     syzbot <syzbot+13a08c0bf4d212766c3c@...kaller.appspotmail.com>,
        davem@...emloft.net, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [crypto?] general protection fault in shash_async_final

On Wed, Jun 14, 2023 at 12:25:14PM +0100, David Howells wrote:
> Here's a reduced testcase for this.  The key seems to be passing MSG_MORE to
> sendmsg() and then not following up with more data before calling recvmsg().
> Apart from not oopsing, I wonder what the behaviour should be here?  Should
> recvmsg() return an error (EAGAIN or ENODATA maybe) or should it close the
> existing operation?

On send if MSG_MORE is set then we don't finalise the hash.

If the user calls recvmsg while the hash hasn't been finalised, then
we will force finalisation (thus rendering the last MSG_MORE moot).

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt