[U-Boot] [PATCH 4/6] bootcount: Configure length limit for I2C bootcount

[Sebastian Reichel]

From: Denis Zalevskiy <denis.zalevs...@ge.com>

Bootcount driver should verify size against the maximum available space. New
configuration parameter adds this capability and keeps backward compatibility by
providing default value.

Signed-off-by: Denis Zalevskiy <denis.zalevs...@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reic...@collabora.co.uk>
---
 drivers/bootcount/Kconfig         |  6 ++++++
 drivers/bootcount/bootcount_i2c.c | 10 ++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/bootcount/Kconfig b/drivers/bootcount/Kconfig
index a5349a62fdc3..e7f2e1ef65e0 100644
--- a/drivers/bootcount/Kconfig
+++ b/drivers/bootcount/Kconfig
@@ -132,4 +132,10 @@ config SYS_BOOTCOUNT_I2C_ADDR
        depends on BOOTCOUNT_I2C
        help
          I2C address of the device used to store bootcounter
+
+config BOOTCOUNT_I2C_LEN
+       int "Maximum length of bootcounter in bytes"
+       default 2
+       depends on BOOTCOUNT_I2C
+
 endif
diff --git a/drivers/bootcount/bootcount_i2c.c 
b/drivers/bootcount/bootcount_i2c.c
index 79d82ad451f3..a8bb611eea9e 100644
--- a/drivers/bootcount/bootcount_i2c.c
+++ b/drivers/bootcount/bootcount_i2c.c
@@ -54,14 +54,15 @@ void bootcount_store(ulong a)
        if (prev_i2c_bus < 0)
                return;
 
-       unsigned char buf[3];
+       unsigned char buf[2];
        int ret;
 
+       BUILD_BUG_ON(CONFIG_BOOTCOUNT_I2C_LEN < sizeof(buf));
        buf[0] = BC_MAGIC;
        buf[1] = (a & 0xff);
        ret = i2c_write(CONFIG_SYS_BOOTCOUNT_I2C_ADDR,
                        CONFIG_SYS_BOOTCOUNT_ADDR,
-                       CONFIG_BOOTCOUNT_ALEN, buf, 2);
+                       CONFIG_BOOTCOUNT_ALEN, buf, sizeof(buf));
        if (ret != 0)
                puts("Error writing bootcount\n");
 
@@ -77,12 +78,13 @@ ulong bootcount_load(void)
        if (prev_i2c_bus < 0)
                return count;
 
-       unsigned char buf[3];
+       unsigned char buf[2];
        int ret;
 
+       BUILD_BUG_ON(CONFIG_BOOTCOUNT_I2C_LEN < sizeof(buf));
        ret = i2c_read(CONFIG_SYS_BOOTCOUNT_I2C_ADDR,
                       CONFIG_SYS_BOOTCOUNT_ADDR,
-                      CONFIG_BOOTCOUNT_ALEN, buf, 2);
+                      CONFIG_BOOTCOUNT_ALEN, buf, sizeof(buf));
        if (ret != 0) {
                puts("Error loading bootcount\n");
                goto out;
-- 
2.18.0

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