Christian Marangi <ansuelsmth@xxxxxxxxx> writes:
> diff --git a/block/partitions/of.c b/block/partitions/of.c
> new file mode 100644
> index 000000000000..bc6200eb86b3
> --- /dev/null
> +++ b/block/partitions/of.c
> @@ -0,0 +1,151 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/blkdev.h>
> +#include <linux/major.h>
> +#include <linux/of.h>
> +#include "check.h"
> +
> +#define BOOT0_STR "boot0"
> +#define BOOT1_STR "boot1"
> +
> +static struct device_node *get_partitions_node(struct device_node *disk_np,
> + struct gendisk *disk)
> +{
> + const char *node_name = "partitions";
> +
> + /*
> + * JEDEC specification 4.4 for eMMC introduced 3 additional partition
> + * present on every eMMC. These additional partition are always hardcoded
> + * from the eMMC driver as boot0, boot1 and rpmb. While rpmb is used to
> + * store keys and exposed as a char device, the other 2 are exposed as
> + * real separate disk with the boot0/1 appended to the disk name.
> + *
> + * Here we parse the disk_name in search for such suffix and select
> + * the correct partition node.
> + */
> + if (disk->major == MMC_BLOCK_MAJOR) {
> + const char *disk_name = disk->disk_name;
> +
> + if (!memcmp(disk_name + strlen(disk_name) - strlen(BOOT0_STR),
> + BOOT0_STR, sizeof(BOOT0_STR)))
> + node_name = "partitions-boot0";
If strlen(disk_name) is less than 5 (and I don't know if that's actually
possible), this well end up doing out-of-bounds access.
We have a strstarts() helper, could you also add a strends() helper that
handles this correctly? Something like
/**
* strends - does @str end with @suffix?
* @str: string to examine
* @suffix: suffix to look for.
*/
static inline bool strends(const char *str, const char *suffix)
{
size_t n = strlen(str);
size_t m = strlen(suffix);
return n >= m && !memcmp(str + n - m, suffix, m);
}
[or name it str_has_suffix() or str_ends_with(), "strends" is not
particularly readable, it's unfortunate that the existing strstarts is
spelled like that].
Rasmus
