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From:   Julia Lawall <Julia.Lawall@inria.fr>
To:     Dmitry Vyukov <dvyukov@google.com>
Cc:     keescook@chromium.org, kernel-janitors@vger.kernel.org,
        Andrey Konovalov <andreyknvl@gmail.com>,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
Subject: [PATCH 17/26] kcov: use array_size
Date:   Fri, 23 Jun 2023 23:14:48 +0200
Message-Id: <20230623211457.102544-18-Julia.Lawall@inria.fr>
In-Reply-To: <20230623211457.102544-1-Julia.Lawall@inria.fr>
References: <20230623211457.102544-1-Julia.Lawall@inria.fr>
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Use array_size to protect against multiplication overflows.

The changes were done using the following Coccinelle semantic patch:

// <smpl>
@@
    expression E1, E2;
    constant C1, C2;
    identifier alloc = {vmalloc,vzalloc};
@@
    
(
      alloc(C1 * C2,...)
|
      alloc(
-           (E1) * (E2)
+           array_size(E1, E2)
      ,...)
)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

---
 kernel/kcov.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kcov.c b/kernel/kcov.c
index 84c717337df0..631444760644 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -900,7 +900,7 @@ void kcov_remote_start(u64 handle)
 	/* Can only happen when in_task(). */
 	if (!area) {
 		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
-		area = vmalloc(size * sizeof(unsigned long));
+		area = vmalloc(array_size(size, sizeof(unsigned long)));
 		if (!area) {
 			kcov_put(kcov);
 			return;