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vim-patch:9.0.1015: without /dev/urandom srand() seed is too predictable (#21303)

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Problem:    Without /dev/urandom srand() seed is too predictable.
Solution:   Use micro seconds and XOR with process ID. (Yasuhiro Matsumoto,
            closes vim/vim#11656)

f0a9c00482

Co-authored-by: Yasuhiro Matsumoto <mattn.jp@gmail.com>
This commit is contained in:
zeertzjq 2022-12-06 09:15:04 +08:00 committed by GitHub
parent 54a1cc0ab0
commit 5199c333a0
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 22 additions and 2 deletions
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5
src/nvim/eval/funcs.c
View File

@ -5145,10 +5145,11 @@ static void init_srand(uint32_t *const x)
}
}
if (dev_urandom_state != OK) {
// Reading /dev/urandom doesn't work, fall back to time().
// Reading /dev/urandom doesn't work, fall back to os_hrtime() XOR with process ID
#endif
// uncrustify:off
*x = (uint32_t)time(NULL);
*x = (uint32_t)os_hrtime();
*x ^= (uint32_t)os_get_pid();
#ifndef MSWIN
}
#endif

19
src/nvim/testdir/test_random.vim
View File

@ -1,5 +1,8 @@
" Tests for srand() and rand()
source check.vim
source shared.vim
func Test_Rand()
let r = srand(123456789)
call assert_equal([1573771921, 319883699, 2742014374, 1324369493], r)
@ -48,4 +51,20 @@ func Test_issue_5587()
call rand()
endfunc
func Test_srand()
CheckNotGui
let cmd = GetVimCommand() .. ' -V -es -c "echo rand()" -c qa!'
let bad = 0
for _ in range(10)
echo cmd
let result1 = system(cmd)
let result2 = system(cmd)
if result1 ==# result2
let bad += 1
endif
endfor
call assert_inrange(0, 4, bad)
endfunc
" vim: shiftwidth=2 sts=2 expandtab