From cc577d0e058b53df5c0fe2ac17890a41d77e94c5 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Sat, 13 Feb 2021 13:59:44 -0500
Subject: fix misuse of getpwuid_r in cuserid

getpwuid_r can return 0 but without a result in the case where there
was no error but no record exists. in that case cuserid was treating
it as success and copying junk out of pw.pw_name to the output buffer.
---
 src/legacy/cuserid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'src/legacy')

diff --git a/src/legacy/cuserid.c b/src/legacy/cuserid.c
index 3ff115a1..07866acf 100644
--- a/src/legacy/cuserid.c
+++ b/src/legacy/cuserid.c
@@ -9,7 +9,8 @@ char *cuserid(char *buf)
 	static char usridbuf[L_cuserid];
 	struct passwd pw, *ppw;
 	long pwb[256];
-	if (getpwuid_r(geteuid(), &pw, (void *)pwb, sizeof pwb, &ppw))
+	getpwuid_r(geteuid(), &pw, (void *)pwb, sizeof pwb, &ppw);
+	if (!ppw)
 		return 0;
 	size_t len = strnlen(pw.pw_name, L_cuserid);
 	if (len == L_cuserid)
-- 
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