diff options
| -rw-r--r-- | util/libreboot-utils/lib/num.c | 6 | ||||
| -rw-r--r-- | util/libreboot-utils/lib/rand.c | 1 |
2 files changed, 3 insertions, 4 deletions
diff --git a/util/libreboot-utils/lib/num.c b/util/libreboot-utils/lib/num.c index d297ab86..f53f0cee 100644 --- a/util/libreboot-utils/lib/num.c +++ b/util/libreboot-utils/lib/num.c @@ -41,10 +41,8 @@ hextonum(char ch_s) if ((unsigned int)(ch - 'a') <= 5) return ch - 'a' + 10; - if (ch == '?' || ch == 'x') { - rset(&rval, sizeof(rval)); - return rval & 0xf; - } + if (ch == '?' || ch == 'x') + return rsize(16); /* <-- with rejection sampling! */ return 16; } diff --git a/util/libreboot-utils/lib/rand.c b/util/libreboot-utils/lib/rand.c index 9304d83a..10831e44 100644 --- a/util/libreboot-utils/lib/rand.c +++ b/util/libreboot-utils/lib/rand.c @@ -86,6 +86,7 @@ rsize(size_t n) if (!n) err_no_cleanup(0, EFAULT, "rsize: division by zero"); + /* rejection sampling (clamp rand to eliminate modulo bias) */ for (; rval >= SIZE_MAX - (SIZE_MAX % n); rset(&rval, sizeof(rval))); return rval % n; |