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author | Tobin C. Harding <me@tobin.cc> | 2018-06-22 02:15:32 +0300 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2018-07-18 04:32:48 +0300 |
commit | 753d433b586d1d43c487e3d660f5778c7c8d58ea (patch) | |
tree | 7f1a030f66811359e8c12c7e4d3668564d919684 /drivers/char/random.c | |
parent | 8ddd6efa56c3fe23df9fe4cf5e2b49cc55416ef4 (diff) | |
download | linux-753d433b586d1d43c487e3d660f5778c7c8d58ea.tar.xz |
random: Return nbytes filled from hw RNG
Currently the function get_random_bytes_arch() has return value 'void'.
If the hw RNG fails we currently fall back to using get_random_bytes().
This defeats the purpose of requesting random material from the hw RNG
in the first place.
There are currently no intree users of get_random_bytes_arch().
Only get random bytes from the hw RNG, make function return the number
of bytes retrieved from the hw RNG.
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'drivers/char/random.c')
-rw-r--r-- | drivers/char/random.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 8e53e9515a1d..34ddfd57419b 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1725,26 +1725,28 @@ EXPORT_SYMBOL(del_random_ready_callback); * key known by the NSA). So it's useful if we need the speed, but * only if we're willing to trust the hardware manufacturer not to * have put in a back door. + * + * Return number of bytes filled in. */ -void get_random_bytes_arch(void *buf, int nbytes) +int __must_check get_random_bytes_arch(void *buf, int nbytes) { + int left = nbytes; char *p = buf; - trace_get_random_bytes_arch(nbytes, _RET_IP_); - while (nbytes) { + trace_get_random_bytes_arch(left, _RET_IP_); + while (left) { unsigned long v; - int chunk = min(nbytes, (int)sizeof(unsigned long)); + int chunk = min_t(int, left, sizeof(unsigned long)); if (!arch_get_random_long(&v)) break; memcpy(p, &v, chunk); p += chunk; - nbytes -= chunk; + left -= chunk; } - if (nbytes) - get_random_bytes(p, nbytes); + return nbytes - left; } EXPORT_SYMBOL(get_random_bytes_arch); |