From: Laura Abbott <labbott@redhat.com>
To: Russell King <linux@armlinux.org.uk>, David Airlie <airlied@linux.ie>
Cc: Laura Abbott <labbott@redhat.com>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Kees Cook <keescook@chromium.org>
Subject: [PATCHv2] drm/i2c: tda998x: Remove VLA usage
Date: Tue, 10 Apr 2018 18:03:30 -0700 [thread overview]
Message-ID: <20180411010330.17866-1-labbott@redhat.com> (raw)
There's an ongoing effort to remove VLAs[1] from the kernel to eventually
turn on -Wvla. The vla in reg_write_range is based on the length of data
passed. The one use of a non-constant size for this range is bounded by
the size buffer passed to hdmi_infoframe_pack which is a fixed size.
Switch to this upper bound.
[1] https://lkml.org/lkml/2018/3/7/621
Signed-off-by: Laura Abbott <labbott@redhat.com>
---
v2: Switch to make the buffer size more transparent and add a bounds
check.
---
drivers/gpu/drm/i2c/tda998x_drv.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 9e67a7b4e3a4..c8b6029b7839 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -466,13 +466,22 @@ reg_read_range(struct tda998x_priv *priv, u16 reg, char *buf, int cnt)
return ret;
}
+#define MAX_WRITE_RANGE_BUF 32
+
static void
reg_write_range(struct tda998x_priv *priv, u16 reg, u8 *p, int cnt)
{
struct i2c_client *client = priv->hdmi;
- u8 buf[cnt+1];
+ /* This is the maximum size of the buffer passed in */
+ u8 buf[MAX_WRITE_RANGE_BUF + 1];
int ret;
+ if (cnt > MAX_WRITE_RANGE_BUF) {
+ dev_err(&client->dev, "Fixed write buffer too small (%d)\n",
+ MAX_WRITE_RANGE_BUF);
+ return;
+ }
+
buf[0] = REG2ADDR(reg);
memcpy(&buf[1], p, cnt);
@@ -679,7 +688,7 @@ static void
tda998x_write_if(struct tda998x_priv *priv, u8 bit, u16 addr,
union hdmi_infoframe *frame)
{
- u8 buf[32];
+ u8 buf[MAX_WRITE_RANGE_BUF];
ssize_t len;
len = hdmi_infoframe_pack(frame, buf, sizeof(buf));
--
2.14.3
next reply other threads:[~2018-04-11 1:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-11 1:03 Laura Abbott [this message]
2018-05-18 18:01 ` [PATCHv2] drm/i2c: tda998x: Remove VLA usage Kees Cook
2018-05-19 10:07 ` Russell King - ARM Linux
2018-05-23 8:46 ` Daniel Vetter
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