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| author |   Kees Cook <keescook@chromium.org> | 2018-06-29 11:44:50 -0700 |
|---|---|---|
| committer |   Florian Fainelli <f.fainelli@gmail.com> | 2018-07-09 10:47:29 -0700 |
| commit | a1547e0bca519b92b09ac5530c6accb7c3f69d1a (patch) | |
| tree | f53f4d6e3dc3045f8c504445a3eec298f23a0409 /drivers/firmware/raspberrypi.c | |
| parent | firmware: raspberrypi: Register hwmon driver (diff) | |
| download | wireguard-linux-a1547e0bca519b92b09ac5530c6accb7c3f69d1a.tar.xz wireguard-linux-a1547e0bca519b92b09ac5530c6accb7c3f69d1a.zip | |
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.c | 10 |
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); |