crypto: af_alg - use struct_size() in sock_kfree_s()

GustavoARSilva · herbertx · commit 91e14842f8ea · 2019-02-28T14:17:59.000+08:00
Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.

So, change the following form:

sizeof(*sgl) + sizeof(sgl-&gt;sg[0]) * (MAX_SGL_ENTS + 1)

to :

struct_size(sgl, sg, MAX_SGL_ENTS + 1)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva &lt;gustavo@embeddedor.com&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
@@ -635,8 +635,7 @@ void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 		}
 
 		list_del(&sgl->list);
-		sock_kfree_s(sk, sgl, sizeof(*sgl) + sizeof(sgl->sg[0]) *
-						     (MAX_SGL_ENTS + 1));
+		sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
 	}
 
 	if (!ctx->used)

Original file line number	Diff line number	Diff line change
`@@ -635,8 +635,7 @@ void af_alg_pull_tsgl(struct sock sk, size_t used, struct scatterlist dst,`
`635`	`635`	`}`
`636`	`636`
`637`	`637`	`list_del(&sgl->list);`
`638`		`- sock_kfree_s(sk, sgl, sizeof(sgl) + sizeof(sgl->sg[0]) `
`639`		`- (MAX_SGL_ENTS + 1));`
	`638`	`+ sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));`
`640`	`639`	`}`
`641`	`640`
`642`	`641`	`if (!ctx->used)`