From: Rusty Russell <rusty@rustcorp.com.au>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: ccan@lists.ozlabs.org, rusty@rustcorp/com.au
Subject: Re: [PATCH 4/7] crypto/hmac_sha256: Remove undefined memset()
Date: Wed, 12 Apr 2017 16:56:13 -0700 [thread overview]
Message-ID: <87wpap5gf6.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20170405122321.GA15755@umbus.fritz.box>
David Gibson <david@gibson.dropbear.id.au> writes:
> [ Unknown signature status ]
> On Tue, Apr 04, 2017 at 11:52:39AM +0930, Paul 'Rusty' Russell wrote:
>> David Gibson <david@gibson.dropbear.id.au> writes:
>> > A memset() with a zero length argument isn't well defined. It *might* be
>> > a no-op, but then it might not. So, test for this case in
>> > hmac_sha256_init().
>>
>> Huh? That seems really odd.
>
> Well.. more precisely, my understanding is that memset(p, x, 0) can't
> be counted on not to dereference p.
That seems nonsensical, though.
> In this case, k_ipad + ksize is past the end of the array, and so not
> a valid pointer to dereference.
The pointer is valid (C's famous one-past-end exception), dereferencing
it is not.
What's the actual coverity error?
Thanks,
Rusty.
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next prev parent reply other threads:[~2017-04-18 3:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-03 11:11 [PATCH 0/7] Coverity David Gibson
2017-04-03 11:11 ` [PATCH 1/7] .travis.yml: Add support for Coverity Scan David Gibson
2017-04-03 12:14 ` David Gibson
2017-04-03 11:11 ` [PATCH 2/7] failtest: Remove memory leak David Gibson
2017-04-03 11:11 ` [PATCH 3/7] tools: Remove fd leak David Gibson
2017-04-03 11:11 ` [PATCH 4/7] crypto/hmac_sha256: Remove undefined memset() David Gibson
2017-04-04 2:22 ` Rusty Russell
2017-04-05 12:23 ` David Gibson
2017-04-12 23:56 ` Rusty Russell [this message]
2017-04-18 4:22 ` Timothy B. Terriberry
2017-04-24 2:30 ` Rusty Russell
2017-04-03 11:11 ` [PATCH 5/7] crypto/ripemd160: Correct badly sized union member David Gibson
2017-04-03 11:11 ` [PATCH 6/7] ccanlint: Fix leak in do_reduce_features() David Gibson
2017-04-03 11:11 ` [PATCH 7/7] net: Add check for failure of setsockopt() David Gibson
2017-04-04 2:23 ` Rusty Russell
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