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random.c: make sure that Random.urandom returns required-length buffer

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getrandom(2) and read(2) (from /dev/urandom) may return a random buffer
whose length is shorter than required.  This change makes sure that they
get enough buffer by using a loop.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61292 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
mame 2017-12-16 00:39:34 +00:00
parent d2333dd92c
commit 0c2f92daad
1 changed files with 20 additions and 9 deletions
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21
random.c
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@ -447,14 +447,21 @@ fill_random_bytes_urandom(void *seed, size_t size)
O_RDONLY, 0); O_RDONLY, 0);
struct stat statbuf; struct stat statbuf;
ssize_t ret = 0; ssize_t ret = 0;
size_t offset = 0;
if (fd < 0) return -1; if (fd < 0) return -1;
rb_update_max_fd(fd); rb_update_max_fd(fd);
if (fstat(fd, &statbuf) == 0 && S_ISCHR(statbuf.st_mode)) { if (fstat(fd, &statbuf) == 0 && S_ISCHR(statbuf.st_mode)) {
ret = read(fd, seed, size); do {
ret = read(fd, ((char*)seed) + offset, size - offset);
if (ret < 0) {
close(fd);
return -1;
}
offset += (size_t)ret;
} while(offset < size);
} }
close(fd); close(fd);
if (ret < 0 || (size_t)ret < size) return -1;
return 0; return 0;
} }
#else #else
@ -518,16 +525,20 @@ fill_random_bytes_syscall(void *seed, size_t size, int need_secure)
static rb_atomic_t try_syscall = 1; static rb_atomic_t try_syscall = 1;
if (try_syscall) { if (try_syscall) {
long ret; long ret;
size_t offset = 0;
int flags = 0; int flags = 0;
if (!need_secure) if (!need_secure)
flags = GRND_NONBLOCK; flags = GRND_NONBLOCK;
do {
errno = 0; errno = 0;
ret = syscall(__NR_getrandom, seed, size, flags); ret = syscall(__NR_getrandom, ((char*)seed) + offset, size - offset, flags);
if (errno == ENOSYS) { if (ret == -1) {
ATOMIC_SET(try_syscall, 0); ATOMIC_SET(try_syscall, 0);
return -1; return -1;
} }
if ((size_t)ret == size) return 0; offset += (size_t)ret;
} while(offset < size);
return 0;
} }
return -1; return -1;
} }