On 4/11/24 01:46, Mark Kettenis wrote:

...

From: Heinrich Schuchardt heinrich.schuchardt@canonical.com Date: Thu, 11 Apr 2024 01:31:16 +0200

The random() function is unsafe to initialize cryptographic data. Use getrandom() which reads from /dev/urandom instead.

getrandom() is available on Linux sine release 3.17 and on BSD.

NACK

getrandom() isn't evailable on OpenBSD. Either use getentropy() or arc4random_buf() instead.

Thanks for reviewing. arc4random_buf() was added to glibc only in 2022. So there might be too many users not using a recent enough Linux distro. So I guess getentropy() is a better choice.

Best regards

Heinrich

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Addresses-Coverity-ID: 312953 Calling risky function Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com

---

tools/image-host.c | 36 +++--------------------------------- 1 file changed, 3 insertions(+), 33 deletions(-)

diff --git a/tools/image-host.c b/tools/image-host.c index b2a0f2e6d16..d30a235baf6 100644 --- a/tools/image-host.c +++ b/tools/image-host.c @@ -13,11 +13,11 @@ #include <fdt_region.h> #include <image.h> #include <version.h>

• #if CONFIG_IS_ENABLED(FIT_SIGNATURE) #include <openssl/pem.h> #include <openssl/evp.h> #endif

+#include <sys/random.h>

/**

• fit_set_hash_value - set hash value in requested has node

@@ -364,36 +364,6 @@ static int fit_image_read_key_iv_data(const char *keydir, const char *key_iv_nam return ret; }

-static int get_random_data(void *data, int size) -{

• unsigned char *tmp = data;
• struct timespec date;
• int i, ret;
• if (!tmp) {

• fprintf(stderr, "%s: pointer data is NULL\n", __func__);
  

• ret = -1;
  

• goto out;
  

• }
• ret = clock_gettime(CLOCK_MONOTONIC, &date);
• if (ret) {

• fprintf(stderr, "%s: clock_gettime has failed (%s)\n", __func__,
  

• 	strerror(errno));
  

• goto out;
  

• }
• srandom(date.tv_nsec);
• for (i = 0; i < size; i++) {

• *tmp = random() & 0xff;
  

• tmp++;
  

• }
• out:
• return ret;

-}

• static int fit_image_setup_cipher(struct image_cipher_info *info, const char *keydir, void *fit, const char *image_name, int image_noffset,

@@ -465,8 +435,8 @@ static int fit_image_setup_cipher(struct image_cipher_info *info, if (ret < 0) goto out; } else {

• /* Generate an ramdom IV */
  

• ret = get_random_data((void *)info->iv, info->cipher->iv_len);
  

• /* Generate a ramdom initialization vector */
  

• ret = getrandom((void *)info->iv, info->cipher->iv_len, 0);
  

  }

  out:

-- 2.43.0