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authorKees Cook <keescook@chromium.org>2018-06-29 11:44:50 -0700
committerFlorian Fainelli <f.fainelli@gmail.com>2018-07-09 10:47:29 -0700
commita1547e0bca519b92b09ac5530c6accb7c3f69d1a (patch)
treef53f4d6e3dc3045f8c504445a3eec298f23a0409 /drivers/firmware/raspberrypi.c
parent70eea1bbb5561154e62b322904b685acb0e52d3e (diff)
firmware: raspberrypi: Remove VLA usage
In the quest to remove all stack VLA usage from the kernel[1], this removes the VLA in favor of a maximum size and adds a sanity check. Existing callers of the firmware interface never need more than 24 bytes (struct gpio_set_config). This chooses 32 just to stay ahead of future growth. v2: Fix the length passed to rpi_firmware_property_list (by anholt, acked by Kees). [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric Anholt <eric@anholt.net> Reviewed-by: Eric Anholt <eric@anholt.net>
Diffstat (limited to 'drivers/firmware/raspberrypi.c')
-rw-r--r--drivers/firmware/raspberrypi.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index 0602626bf72d..a200a2174611 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -21,6 +21,8 @@
#define MBOX_DATA28(msg) ((msg) & ~0xf)
#define MBOX_CHAN_PROPERTY 8
+#define MAX_RPI_FW_PROP_BUF_SIZE 32
+
static struct platform_device *rpi_hwmon;
struct rpi_firmware {
@@ -145,18 +147,22 @@ int rpi_firmware_property(struct rpi_firmware *fw,
/* Single tags are very small (generally 8 bytes), so the
* stack should be safe.
*/
- u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];
+ u8 data[sizeof(struct rpi_firmware_property_tag_header) +
+ MAX_RPI_FW_PROP_BUF_SIZE];
struct rpi_firmware_property_tag_header *header =
(struct rpi_firmware_property_tag_header *)data;
int ret;
+ if (WARN_ON(buf_size > sizeof(data) - sizeof(*header)))
+ return -EINVAL;
+
header->tag = tag;
header->buf_size = buf_size;
header->req_resp_size = 0;
memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
tag_data, buf_size);
- ret = rpi_firmware_property_list(fw, &data, sizeof(data));
+ ret = rpi_firmware_property_list(fw, &data, buf_size + sizeof(*header));
memcpy(tag_data,
data + sizeof(struct rpi_firmware_property_tag_header),
buf_size);