linux-kernel - RE: [PATCH] rfc4106, Intel, AES-NI: Don't leak memory in rfc4106_set_hash

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Message-ID: <alpine.LNX.2.00.1102062039080.13593@swampdragon.chaosbits.net>
Date:	Sun, 6 Feb 2011 20:43:22 +0100 (CET)
From:	Jesper Juhl <jj@...osbits.net>
To:	"Struk, Tadeusz" <tadeusz.struk@...el.com>,
	Herbert Xu <herbert@...dor.apana.org.au>
cc:	"linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"David S. Miller" <davem@...emloft.net>,
	"Huang, Ying" <ying.huang@...el.com>,
	"Hoban, Adrian" <adrian.hoban@...el.com>,
	"Paoloni, Gabriele" <gabriele.paoloni@...el.com>,
	"O Mahony, Aidan" <aidan.o.mahony@...el.com>
Subject: RE: [PATCH] rfc4106, Intel, AES-NI: Don't leak memory in
 rfc4106_set_hash_subkey().

On Wed, 19 Jan 2011, Struk, Tadeusz wrote:

> Hi Jesper,

Hi Tadeusz,

> We have tested your changes and all is fine.
> Thank you for identifying this issue.

You are welcome. But I believe I made a mistake in that patch. I looked at 
it again and I'm convinced that the 'out' label should not exist. The 
jump to it will still leak 'ctr_tfm' - don't you agree?

I believe the patch should look like this instead:


Signed-off-by: Jesper Juhl <jj@...osbits.net>
---
 aesni-intel_glue.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index e1e60c7..4a8c015 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -873,21 +873,19 @@ rfc4106_set_hash_subkey(u8 *hash_subkey, const u8 *key, unsigned int key_len)
 	crypto_ablkcipher_clear_flags(ctr_tfm, ~0);
 
 	ret = crypto_ablkcipher_setkey(ctr_tfm, key, key_len);
-	if (ret) {
-		crypto_free_ablkcipher(ctr_tfm);
-		return ret;
-	}
+	if (ret)
+		goto out_free_ablkcipher;
 
 	req = ablkcipher_request_alloc(ctr_tfm, GFP_KERNEL);
 	if (!req) {
-		crypto_free_ablkcipher(ctr_tfm);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out_free_ablkcipher;
 	}
 
 	req_data = kmalloc(sizeof(*req_data), GFP_KERNEL);
 	if (!req_data) {
-		crypto_free_ablkcipher(ctr_tfm);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto out_free_request;
 	}
 	memset(req_data->iv, 0, sizeof(req_data->iv));
 
@@ -913,8 +911,10 @@ rfc4106_set_hash_subkey(u8 *hash_subkey, const u8 *key, unsigned int key_len)
 		if (!ret)
 			ret = req_data->result.err;
 	}
+out_free_request:
 	ablkcipher_request_free(req);
 	kfree(req_data);
+out_free_ablkcipher:
 	crypto_free_ablkcipher(ctr_tfm);
 	return ret;
 }


Herbert: If Tadeusz agrees, could you please replace the patch you merged 
with the one above?

-- 
Jesper Juhl <jj@...osbits.net>            http://www.chaosbits.net/
Plain text mails only, please.
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html

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