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  1. 13 4月, 2022 2 次提交
    • J
      random: make random_get_entropy() return an unsigned long · b0c3e796
      由 Jason A. Donenfeld 提交于 
      Some implementations were returning type `unsigned long`, while others
that fell back to get_cycles() were implicitly returning a `cycles_t` or
an untyped constant int literal. That makes for weird and confusing
code, and basically all code in the kernel already handled it like it
was an `unsigned long`. I recently tried to handle it as the largest
type it could be, a `cycles_t`, but doing so doesn't really help with
much.

Instead let's just make random_get_entropy() return an unsigned long all
the time. This also matches the commonly used `arch_get_random_long()`
function, so now RDRAND and RDTSC return the same sized integer, which
means one can fallback to the other more gracefully.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
      b0c3e796
    • J
      random: allow partial reads if later user copies fail · 5209aed5
      由 Jason A. Donenfeld 提交于 
      Rather than failing entirely if a copy_to_user() fails at some point,
instead we should return a partial read for the amount that succeeded
prior, unless none succeeded at all, in which case we return -EFAULT as
before.

This makes it consistent with other reader interfaces. For example, the
following snippet for /dev/zero outputs "4" followed by "1":

  int fd;
  void *x = mmap(NULL, 4096, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  assert(x != MAP_FAILED);
  fd = open("/dev/zero", O_RDONLY);
  assert(fd >= 0);
  printf("%zd\n", read(fd, x, 4));
  printf("%zd\n", read(fd, x + 4095, 4));
  close(fd);

This brings that same standard behavior to the various RNG reader
interfaces.

While we're at it, we can streamline the loop logic a little bit.
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
      5209aed5
  3. 09 4月, 2022 3 次提交
  5. 08 4月, 2022 3 次提交
  7. 07 4月, 2022 29 次提交
  9. 06 4月, 2022 3 次提交