This commit reverts the previous change to use system provided
entropy, as (SYS_)getrandom is very slow on Linux because it is
a syscall.
The change introduced in this commit adds a new call isc_nonce_buf
that uses CSPRNG from cryptographic library provider to generate
secure data that can be and must be used for generating nonces.
Example usage would be DNS cookies.
The isc_random() API has been changed to use fast PRNG that is not
cryptographically secure, but runs entirely in user space. Two
contestants have been considered xoroshiro family of the functions
by Villa&Blackman and PCG by O'Neill. After a consideration the
xoshiro128starstar function has been used as uint32_t random number
provider because it is very fast and has good enough properties
for our usage pattern.
The other change introduced in the commit is the more extensive usage
of isc_random_uniform in places where the usage pattern was
isc_random() % n to prevent modulo bias. For usage patterns where
only 16 or 8 bits are needed (DNS Message ID), the isc_random()
functions has been renamed to isc_random32(), and isc_random16() and
isc_random8() functions have been introduced by &-ing the
isc_random32() output with 0xffff and 0xff. Please note that the
functions that uses stripped down bit count doesn't pass our
NIST SP 800-22 based random test.
The three functions has been modeled after the arc4random family of
functions, and they will always return random bytes.
The isc_random family of functions internally use these CSPRNG (if available):
1. getrandom() libc call (might be available on Linux and Solaris)
2. SYS_getrandom syscall (might be available on Linux, detected at runtime)
3. arc4random(), arc4random_buf() and arc4random_uniform() (available on BSDs and Mac OS X)
4. crypto library function:
4a. RAND_bytes in case OpenSSL
4b. pkcs_C_GenerateRandom() in case PKCS#11 library
4610. [func] The "new-zones-directory" option specifies the
location of NZF or NZD files for storing
configuration of zones added by "rndc addzone".
Thanks to Petr Menšík. [RT #44853]
Based on a patch sent in by Tony Finch <dot@dotat.at>.
Also fix win32 implementation of isc_file_openunique() to use a random
filename instead of using the process id.
3999. [func] "mkeys" and "nzf" files are now named after
their corresponding views, unless the view name
contains characters that would be incompatible
with use in a filename (i.e., slash, backslash,
or capital letters). If a view name does contain
these characters, the files will still be named
using a cryptographic hash of the view name.
Regardless of this, if a file using the old name
format is found to exist, it will continue to be
used. [RT #37704]
- check for mmap() in configure
- implement isc_file_mmap() and isc_file_munmap() to do
malloc()/read() and free() when run on systems that do not
support mmap().
