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| author | Mattias Engdegård <mattiase@acm.org> | 2019-12-29 13:51:48 +0100 |
|---|---|---|
| committer | Mattias Engdegård <mattiase@acm.org> | 2019-12-29 13:55:25 +0100 |
| commit | aa0c679f484347d20ab6f7c0f75f32f5e360cb89 (patch) | |
| tree | 1471501c2d1effaa28cf933cf52681d635a41fc5 /lisp/emacs-lisp | |
| parent | d6922db49dea33ac2bca8b33d24763cc7b2e4cd7 (diff) | |
| download | emacs-aa0c679f484347d20ab6f7c0f75f32f5e360cb89.tar.gz emacs-aa0c679f484347d20ab6f7c0f75f32f5e360cb89.tar.bz2 emacs-aa0c679f484347d20ab6f7c0f75f32f5e360cb89.zip | |
Avoid unbounded growth of cl-random-state components (bug#38753)
* lisp/emacs-lisp/cl-extra.el (cl-random):
Perform the modulo 2**23 operation before updating the state instead
of after. The result is always the same, but it prevents the state
from growing into arbitrary large bignums.
Patch from Christopher Wellons.
Diffstat (limited to 'lisp/emacs-lisp')
| -rw-r--r-- | lisp/emacs-lisp/cl-extra.el | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lisp/emacs-lisp/cl-extra.el b/lisp/emacs-lisp/cl-extra.el index 7e9d8fe870b..2e0b37c14de 100644 --- a/lisp/emacs-lisp/cl-extra.el +++ b/lisp/emacs-lisp/cl-extra.el @@ -469,7 +469,7 @@ Optional second arg STATE is a random-state object." (while (< (setq i (1+ i)) 200) (cl-random 2 state)))) (let* ((i (cl-callf (lambda (x) (% (1+ x) 55)) (cl--random-state-i state))) (j (cl-callf (lambda (x) (% (1+ x) 55)) (cl--random-state-j state))) - (n (logand 8388607 (aset vec i (- (aref vec i) (aref vec j)))))) + (n (aset vec i (logand 8388607 (- (aref vec i) (aref vec j)))))) (if (integerp lim) (if (<= lim 512) (% n lim) (if (> lim 8388607) (setq n (+ (ash n 9) (cl-random 512 state)))) |