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Subject[PATCH] usb: typec: tps6598x: Remove VLA usage
In the quest to remove all stack VLA usage from the kernel[1], this
uses the maximum buffer size and adds a sanity check.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/usb/typec/tps6598x.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/typec/tps6598x.c b/drivers/usb/typec/tps6598x.c
index 4b4c8d271b27..396193f85e6d 100644
--- a/drivers/usb/typec/tps6598x.c
+++ b/drivers/usb/typec/tps6598x.c
@@ -81,12 +81,17 @@ struct tps6598x {
struct typec_capability typec_cap;
};

+#define TPS_MAX_LEN sizeof(u64)
+
static int
tps6598x_block_read(struct tps6598x *tps, u8 reg, void *val, size_t len)
{
- u8 data[len + 1];
+ u8 data[TPS_MAX_LEN + 1];
int ret;

+ if (WARN_ON(len + 1 > sizeof(data)))
+ return -EINVAL;
+
if (!tps->i2c_protocol)
return regmap_raw_read(tps->regmap, reg, val, len);

--
2.17.1

--
Kees Cook
Pixel Security

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