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Message-Id: <20220409001047.234283-1-Jason@zx2c4.com>
Date: Sat, 9 Apr 2022 02:10:47 +0200
From: "Jason A. Donenfeld" <Jason@...c4.com>
To: musl@...ts.openwall.com
Cc: "Jason A. Donenfeld" <Jason@...c4.com>
Subject: [PATCH] getentropy: fail if buffer not completely filled
The man page for getentropy says that it either completely succeeds or
completely fails, and indeed this is what glibc does. However, musl has
a condition where it breaks out of the loop early, yet still returns a
success. This patch fixes that by returning a success only if the buffer
is completely filled. While we're at it, prevent an unexpected infinite
loop if the function returns 0, the same way glibc does, just in case.
---
src/misc/getentropy.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/src/misc/getentropy.c b/src/misc/getentropy.c
index 651ea95f..5b2fc7a1 100644
--- a/src/misc/getentropy.c
+++ b/src/misc/getentropy.c
@@ -6,7 +6,7 @@
int getentropy(void *buffer, size_t len)
{
- int cs, ret = 0;
+ int cs, ret;
char *pos = buffer;
if (len > 256) {
@@ -18,16 +18,19 @@ int getentropy(void *buffer, size_t len)
while (len) {
ret = getrandom(pos, len, 0);
- if (ret < 0) {
+ if (ret <= 0) {
if (errno == EINTR) continue;
else break;
}
pos += ret;
len -= ret;
- ret = 0;
}
pthread_setcancelstate(cs, 0);
- return ret;
+ if (len) {
+ errno = EIO;
+ return -1;
+ }
+ return 0;
}
--
2.35.1
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