From: Dmitry V. Levin <ldv@altlinux.org>
Date: Sun, 9 Jul 2017 18:43:34 +0000 (+0000)
Subject: net: enhance decoding of setsockopt's SO_LINGER negative option length
X-Git-Tag: v4.19~294
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b5f7cde8a58e1215f4379dd4b2b1b9e366275cb4;p=strace

net: enhance decoding of setsockopt's SO_LINGER negative option length

* net.c (print_set_linger): Treat negative option length as invalid
to match the kernel behaviour.
* tests/so_linger.c (main): Check it.
---

diff --git a/net.c b/net.c
index 78325da8..934e3ecf 100644
--- a/net.c
+++ b/net.c
@@ -443,19 +443,17 @@ print_sockopt_fd_level_name(struct tcb *tcp, int fd, unsigned int level,
 
 static void
 print_set_linger(struct tcb *const tcp, const kernel_ulong_t addr,
-		 const unsigned int len)
+		 const int len)
 {
 	struct linger linger;
 
-	if (len < sizeof(linger) ||
-	    umove(tcp, addr, &linger) < 0) {
+	if (len < (int) sizeof(linger)) {
 		printaddr(addr);
-		return;
+	} else if (!umove_or_printaddr(tcp, addr, &linger)) {
+		PRINT_FIELD_D("{", linger, l_onoff);
+		PRINT_FIELD_D(", ", linger, l_linger);
+		tprints("}");
 	}
-
-	PRINT_FIELD_D("{", linger, l_onoff);
-	PRINT_FIELD_D(", ", linger, l_linger);
-	tprints("}");
 }
 
 static void
diff --git a/tests/so_linger.c b/tests/so_linger.c
index 8f106349..4dc994bf 100644
--- a/tests/so_linger.c
+++ b/tests/so_linger.c
@@ -83,6 +83,11 @@ main(void)
 	       fd, linger->l_onoff, linger->l_linger,
 	       (unsigned int) sizeof(*linger) + 1, errstr);
 
+	/* setsockopt with optlen < 0 - EINVAL */
+	set_linger(fd, linger, -1U);
+	printf("setsockopt(%d, SOL_SOCKET, SO_LINGER, %p, -1) = %s\n",
+	       fd, linger, errstr);
+
 	/* setsockopt with optlen smaller than necessary - EINVAL */
 	set_linger(fd, linger, sizeof(linger->l_onoff));
 	printf("setsockopt(%d, SOL_SOCKET, SO_LINGER, %p, %d) = %s\n",