Re: [PATCH] Crypto: Don't use err uninitialized in algif_hash.c:hash_sendmsg()

On Mon, 27 Jun 2011, Herbert Xu wrote:

On Sun, Jun 26, 2011 at 11:23:06PM +0200, Jesper Juhl wrote:

quoted

If af_alg_make_sg() returns <0 in hash_sendmsg() we'll jump to the
'unlock' label without having set 'err' to anything. At the 'unlock'
label the value of 'err' is tested to determine return value of the
function - not good to base that on a uninitialized variable.

This patch sets 'err' to the return value of hash_sendmsg() before the
'goto' when the value is less than zero, which seems to me to be the
proper thing to do.

Signed-off-by: Jesper Juhl <redacted>

Thanks for catching this!

You're welcome.

quoted

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 62122a1..1847544 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c

@@ -68,9 +68,10 @@ static int hash_sendmsg(struct kiocb *unused, struct socket *sock,
 			int newlen;
 
 			newlen = af_alg_make_sg(&ctx->sgl, from, len, 0);
-			if (newlen < 0)
+			if (newlen < 0) {
+				err = newlen;
 				goto unlock;
-
+			}

This isn't quite what we want though.  The error from af_alg_make_sg
should only be fatal if we haven't sent anything at all.  That is,
it's OK to get an error on the second try.

So I'm going to tweak your patch a little bit and apply this:

Ok. Guess I didn't quite understand what was going on there. Thank you for 
fixing it up.

-- 
Jesper Juhl [off-list ref]       http://www.chaosbits.net/
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