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Message-Id: <20220409225851.715796-2-Jason@zx2c4.com>
Date: Sun, 10 Apr 2022 00:58:50 +0200
From: "Jason A. Donenfeld" <Jason@...c4.com>
To: Rich Felker <dalias@...c.org>,
musl@...ts.openwall.com
Cc: "Jason A. Donenfeld" <Jason@...c4.com>
Subject: [PATCH v3] getentropy: fail if buffer not completely filled
The man page for getentropy says that it either completely succeeds or
completely fails for values < 256, so we can simplify this scenario by
omitting the loop. As a safeguard, we still return EIO if it returns
short, but otherwise we pass the error on through to the caller.
---
Changes v2->v3:
- v3 gets rid of the loop entirely.
src/misc/getentropy.c | 24 +++++++++---------------
1 file changed, 9 insertions(+), 15 deletions(-)
diff --git a/src/misc/getentropy.c b/src/misc/getentropy.c
index 651ea95f..e8cb4d02 100644
--- a/src/misc/getentropy.c
+++ b/src/misc/getentropy.c
@@ -6,8 +6,8 @@
int getentropy(void *buffer, size_t len)
{
- int cs, ret = 0;
- char *pos = buffer;
+ ssize_t ret;
+ int cs;
if (len > 256) {
errno = EIO;
@@ -15,19 +15,13 @@ int getentropy(void *buffer, size_t len)
}
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
-
- while (len) {
- ret = getrandom(pos, len, 0);
- if (ret < 0) {
- if (errno == EINTR) continue;
- else break;
- }
- pos += ret;
- len -= ret;
- ret = 0;
- }
-
+ ret = getrandom(buffer, len, 0);
pthread_setcancelstate(cs, 0);
- return ret;
+ if (ret != len) {
+ if (ret >= 0)
+ errno = EIO;
+ return -1;
+ }
+ return 0;
}
--
2.35.1
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