linux-hardening - [PATCH v4 2/3] drivers/soc/renesas: Prefer memcpy over strcpy

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Date:   Sun,  8 Aug 2021 14:50:11 +0200
From:   Len Baker <len.baker@....com>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
        Santosh Shilimkar <ssantosh@...nel.org>
Cc:     Len Baker <len.baker@....com>, Kees Cook <keescook@...omium.org>,
        David Laight <David.Laight@...LAB.COM>,
        Robin Murphy <robin.murphy@....com>,
        linux-hardening@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v4 2/3] drivers/soc/renesas: Prefer memcpy over strcpy

strcpy() performs no bounds checking on the destination buffer. This
could result in linear overflows beyond the end of the buffer, leading
to all kinds of misbehaviors. So, use memcpy() as a safe replacement.

This is a previous step in the path to remove the strcpy() function
entirely from the kernel.

Signed-off-by: Len Baker <len.baker@....com>
---
 drivers/soc/renesas/r8a779a0-sysc.c | 6 ++++--
 drivers/soc/renesas/rcar-sysc.c     | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/renesas/r8a779a0-sysc.c b/drivers/soc/renesas/r8a779a0-sysc.c
index d464ffa1be33..7410b9fa9846 100644
--- a/drivers/soc/renesas/r8a779a0-sysc.c
+++ b/drivers/soc/renesas/r8a779a0-sysc.c
@@ -404,19 +404,21 @@ static int __init r8a779a0_sysc_pd_init(void)
 	for (i = 0; i < info->num_areas; i++) {
 		const struct r8a779a0_sysc_area *area = &info->areas[i];
 		struct r8a779a0_sysc_pd *pd;
+		size_t n;

 		if (!area->name) {
 			/* Skip NULLified area */
 			continue;
 		}

-		pd = kzalloc(sizeof(*pd) + strlen(area->name) + 1, GFP_KERNEL);
+		n = strlen(area->name) + 1;
+		pd = kzalloc(sizeof(*pd) + n, GFP_KERNEL);
 		if (!pd) {
 			error = -ENOMEM;
 			goto out_put;
 		}

-		strcpy(pd->name, area->name);
+		memcpy(pd->name, area->name, n);
 		pd->genpd.name = pd->name;
 		pd->pdr = area->pdr;
 		pd->flags = area->flags;
diff --git a/drivers/soc/renesas/rcar-sysc.c b/drivers/soc/renesas/rcar-sysc.c
index 53387a72ca00..b0a80de34c98 100644
--- a/drivers/soc/renesas/rcar-sysc.c
+++ b/drivers/soc/renesas/rcar-sysc.c
@@ -396,19 +396,21 @@ static int __init rcar_sysc_pd_init(void)
 	for (i = 0; i < info->num_areas; i++) {
 		const struct rcar_sysc_area *area = &info->areas[i];
 		struct rcar_sysc_pd *pd;
+		size_t n;

 		if (!area->name) {
 			/* Skip NULLified area */
 			continue;
 		}

-		pd = kzalloc(sizeof(*pd) + strlen(area->name) + 1, GFP_KERNEL);
+		n = strlen(area->name) + 1;
+		pd = kzalloc(sizeof(*pd) + n, GFP_KERNEL);
 		if (!pd) {
 			error = -ENOMEM;
 			goto out_put;
 		}

-		strcpy(pd->name, area->name);
+		memcpy(pd->name, area->name, n);
 		pd->genpd.name = pd->name;
 		pd->ch.chan_offs = area->chan_offs;
 		pd->ch.chan_bit = area->chan_bit;
--
2.25.1