MFC r287345:

Drop group privileges after opening the kvm descriptor, otherwise, the code
would not drop privileges as expected.

While there also add checks for the drop and bail out immediately if we
failed.

1 files changed, 4 insertions, 10 deletions

diff --git a/usr.bin/bluetooth/btsockstat/btsockstat.c b/usr.bin/bluetooth/btsockstat/btsockstat.c
index f63ee1f..95a1680 100644
--- a/usr.bin/bluetooth/btsockstat/btsockstat.c
+++ b/usr.bin/bluetooth/btsockstat/btsockstat.c
@@ -154,9 +154,9 @@ main(int argc, char *argv[])
 	 * Discard setgid privileges if not the running kernel so that
 	 * bad guys can't print interesting stuff from kernel memory.
 	 */
-
 	if (memf != NULL)
-		setgid(getgid());
+		if (setgid(getgid()) != 0)
+			err(1, "setgid");
 
 	kvmd = kopen(memf);
 	if (kvmd == NULL)
@@ -583,15 +583,9 @@ kopen(char const *memf)
 	kvm_t	*kvmd = NULL;
 	char	 errbuf[_POSIX2_LINE_MAX];
 
-	/*
-	 * Discard setgid privileges if not the running kernel so that 
-	 * bad guys can't print interesting stuff from kernel memory.
-	 */
-
-	if (memf != NULL)
-		setgid(getgid());   
-
 	kvmd = kvm_openfiles(NULL, memf, NULL, O_RDONLY, errbuf);
+	if (setgid(getgid()) != 0)
+		err(1, "setgid");
 	if (kvmd == NULL) {
 		warnx("kvm_openfiles: %s", errbuf);
 		return (NULL);