From: Dmitry V. Levin <ldv@altlinux.org>
Date: Mon, 2 Mar 2015 02:13:03 +0000 (+0000)
Subject: tests/uid16: skip if real uid is larger than 16bit
X-Git-Tag: v4.10~38
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=77e0d2dccc2487923325571f02cba5c377d5bb9a;p=strace

tests/uid16: skip if real uid is larger than 16bit

* tests/uid16.c (main): Skip if the uid returned by getuid matches
/proc/sys/kernel/overflowuid.
---

diff --git a/tests/uid16.c b/tests/uid16.c
index be5cec6d..a2006d7f 100644
--- a/tests/uid16.c
+++ b/tests/uid16.c
@@ -4,6 +4,7 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <sys/syscall.h>
 
 int
@@ -38,6 +39,21 @@ main(void)
 	int *list = 0;
 
 	uid = syscall(__NR_getuid);
+
+	(void) close(0);
+	if (open("/proc/sys/kernel/overflowuid", O_RDONLY) == 0) {
+		/* we trust the kernel */
+		char buf[sizeof(int)*3];
+		int n = read(0, buf, sizeof(buf) - 1);
+		if (n) {
+			buf[n] = '\0';
+			n = atoi(buf);
+			if (uid == n)
+				return 77;
+		}
+		close(0);
+	}
+
 	assert(syscall(__NR_setuid, uid) == 0);
 	{
 		/*