random: entropy: Return error in csrand
Propagate driver error when getting entropy data when calling a cryptographically secure random generator. Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
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4f2c107389
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1 changed files with 19 additions and 7 deletions
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@ -46,7 +46,7 @@ u32_t sys_rand32_get(void)
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}
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#endif /* CONFIG_ENTROPY_DEVICE_RANDOM_GENERATOR */
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static void rand_get(u8_t *dst, size_t outlen)
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static int rand_get(u8_t *dst, size_t outlen, bool csrand)
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{
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struct device *dev = entropy_driver;
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u32_t random_num;
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@ -67,6 +67,14 @@ static void rand_get(u8_t *dst, size_t outlen)
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ret = entropy_get_entropy(dev, dst, outlen);
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if (unlikely(ret < 0)) {
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/* Don't try to fill the buffer in case of
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* cryptographically secure random numbers, just
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* propagate the driver error.
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*/
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if (csrand) {
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return ret;
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}
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/* Use system timer in case the entropy device couldn't deliver
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* 32-bit of data. There's not much that can be done in this
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* situation. An __ASSERT() isn't used here as the HWRNG might
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@ -89,12 +97,14 @@ static void rand_get(u8_t *dst, size_t outlen)
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len += blocksize;
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}
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}
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return 0;
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}
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#if defined(CONFIG_ENTROPY_DEVICE_RANDOM_GENERATOR)
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void sys_rand_get(void *dst, size_t outlen)
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{
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return rand_get(dst, outlen);
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rand_get(dst, outlen, false);
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}
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#endif /* CONFIG_ENTROPY_DEVICE_RANDOM_GENERATOR */
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@ -102,11 +112,13 @@ void sys_rand_get(void *dst, size_t outlen)
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int sys_csrand_get(void *dst, size_t outlen)
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{
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rand_get(dst, outlen);
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/* need deeper inspection on hardware based RNG error cases. Right
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* now the assumption is that the HW will continue providing a stream
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* of RNG values
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*/
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if (rand_get(dst, outlen, true) != 0) {
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/* Is it the only error it should return ? entropy_sam
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* can return -ETIMEDOUT for example
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*/
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return -EIO;
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}
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return 0;
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}
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