From: Sami Kerola <kerolasa@iki.fi>
Date: Sat, 31 Oct 2015 19:21:13 +0000 (+0000)
Subject: login: fix stat(2) race
X-Git-Tag: v2.28-rc1~285
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a64e268224a142210e135c2b409c4f65743e476a;p=thirdparty%2Futil-linux.git

login: fix stat(2) race

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
---

diff --git a/login-utils/login.c b/login-utils/login.c
index 0e45de7ac3..b70846771c 100644
--- a/login-utils/login.c
+++ b/login-utils/login.c
@@ -256,13 +256,11 @@ static void motd(void)
 		struct stat st;
 		int fd;
 
-		if (stat(motdfile, &st) || !st.st_size)
-			continue;
 		fd = open(motdfile, O_RDONLY, 0);
 		if (fd < 0)
 			continue;
-
-		sendfile(fileno(stdout), fd, NULL, st.st_size);
+		if (!fstat(fd, &st) && st.st_size)
+			sendfile(fileno(stdout), fd, NULL, st.st_size);
 		close(fd);
 	}