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From: Eric Biggers <ebiggers@kernel.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-crypto@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	herbert@gondor.apana.org.au, will@kernel.org,
	kernel-team@android.com
Subject: Re: [PATCH v3 1/7] crypto: handle zero sized AEAD inputs correctly
Date: Wed, 12 May 2021 13:04:37 -0700	[thread overview]
Message-ID: <YJw01Z3oxwY5Sfpa@gmail.com> (raw)
In-Reply-To: <20210512184439.8778-2-ardb@kernel.org>

On Wed, May 12, 2021 at 08:44:33PM +0200, Ard Biesheuvel wrote:
> There are corner cases where skcipher_walk_aead_[en|de]crypt() may be
> invoked with a zero sized input, which is not rejected by the walker
> code, but results in the skcipher_walk structure to not be fully
> initialized. This will leave stale values in its page and buffer
> members, which will be subsequently passed to kfree() or free_page() by
> skcipher_walk_done(), resulting in a crash if those routines fail to
> identify them as in valid inputs.
> 
> Fix this by setting page and buffer to NULL even if the size of the
> input is zero.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Is this fixing an existing bug, or only a bug that got exposed by this patchset?
It would be helpful to make that clear (and if it fixes an existing bug, include
a Fixes tag).

Also, skcipher_walk_virt() doesn't set page and buffer to NULL, as it is
currently expected that skcipher_walk_done() is only called when
walk.nbytes != 0.  Is something different for skcipher_walk_aead_[en|de]crypt()?

- Eric

WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers <ebiggers@kernel.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-crypto@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	herbert@gondor.apana.org.au, will@kernel.org,
	kernel-team@android.com
Subject: Re: [PATCH v3 1/7] crypto: handle zero sized AEAD inputs correctly
Date: Wed, 12 May 2021 13:04:37 -0700	[thread overview]
Message-ID: <YJw01Z3oxwY5Sfpa@gmail.com> (raw)
In-Reply-To: <20210512184439.8778-2-ardb@kernel.org>

On Wed, May 12, 2021 at 08:44:33PM +0200, Ard Biesheuvel wrote:
> There are corner cases where skcipher_walk_aead_[en|de]crypt() may be
> invoked with a zero sized input, which is not rejected by the walker
> code, but results in the skcipher_walk structure to not be fully
> initialized. This will leave stale values in its page and buffer
> members, which will be subsequently passed to kfree() or free_page() by
> skcipher_walk_done(), resulting in a crash if those routines fail to
> identify them as in valid inputs.
> 
> Fix this by setting page and buffer to NULL even if the size of the
> input is zero.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Is this fixing an existing bug, or only a bug that got exposed by this patchset?
It would be helpful to make that clear (and if it fixes an existing bug, include
a Fixes tag).

Also, skcipher_walk_virt() doesn't set page and buffer to NULL, as it is
currently expected that skcipher_walk_done() is only called when
walk.nbytes != 0.  Is something different for skcipher_walk_aead_[en|de]crypt()?

- Eric

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  reply	other threads:[~2021-05-12 21:08 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-12 18:44 [PATCH v3 0/7] running kernel mode SIMD with softirqs disabled Ard Biesheuvel
2021-05-12 18:44 ` Ard Biesheuvel
2021-05-12 18:44 ` [PATCH v3 1/7] crypto: handle zero sized AEAD inputs correctly Ard Biesheuvel
2021-05-12 18:44   ` Ard Biesheuvel
2021-05-12 20:04   ` Eric Biggers [this message]
2021-05-12 20:04     ` Eric Biggers
2021-05-12 21:24     ` Ard Biesheuvel
2021-05-12 21:24       ` Ard Biesheuvel
2021-05-21  7:55       ` Herbert Xu
2021-05-21  7:55         ` Herbert Xu
2021-05-21  9:28         ` Ard Biesheuvel
2021-05-21  9:28           ` Ard Biesheuvel
2021-05-12 18:44 ` [PATCH v3 2/7] crypto: aead - disallow en/decrypt for non-task or non-softirq context Ard Biesheuvel
2021-05-12 18:44   ` Ard Biesheuvel
2021-05-12 20:06   ` Eric Biggers
2021-05-12 20:06     ` Eric Biggers
2021-05-12 21:24     ` Ard Biesheuvel
2021-05-12 21:24       ` Ard Biesheuvel
2021-05-12 18:44 ` [PATCH v3 3/7] crypto: skcipher " Ard Biesheuvel
2021-05-12 18:44   ` Ard Biesheuvel
2021-05-12 18:44 ` [PATCH v3 4/7] crypto: arm64/gcm-aes-ce - remove non-SIMD fallback path Ard Biesheuvel
2021-05-12 18:44   ` Ard Biesheuvel
2021-05-12 18:44 ` [PATCH v3 5/7] crypto: arm64/aes-neonbs - stop using SIMD helper for skciphers Ard Biesheuvel
2021-05-12 18:44   ` Ard Biesheuvel
2021-05-12 20:08   ` Eric Biggers
2021-05-12 20:08     ` Eric Biggers
2021-05-12 21:25     ` Ard Biesheuvel
2021-05-12 21:25       ` Ard Biesheuvel
2021-05-12 18:44 ` [PATCH v3 6/7] crypto: arm64/aes-ce " Ard Biesheuvel
2021-05-12 18:44   ` Ard Biesheuvel
2021-05-12 18:44 ` [PATCH v3 7/7] crypto: arm64/aes-ccm - remove non-SIMD fallback path Ard Biesheuvel
2021-05-12 18:44   ` Ard Biesheuvel
2021-05-12 20:11 ` [PATCH v3 0/7] running kernel mode SIMD with softirqs disabled Eric Biggers
2021-05-12 20:11   ` Eric Biggers
2021-05-12 21:31   ` Ard Biesheuvel
2021-05-12 21:31     ` Ard Biesheuvel

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