From: Dmitry V. Levin <ldv@altlinux.org>
Date: Sat, 8 Jul 2017 14:57:44 +0000 (+0000)
Subject: net: accept arbitrary option length for getsockopt's SO_LINGER
X-Git-Tag: v4.19~317
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4c14d39332f8e56909f8bf5527b355a40cbf13fb;p=strace

net: accept arbitrary option length for getsockopt's SO_LINGER

* net.c (print_linger): Rename to print_set_linger.
(print_setsockopt): Replace print_linger with print_set_linger.
(print_get_linger): New function that accepts arbitrary option length
to match the kernel behaviour.
(print_getsockopt): Replace print_linger with print_get_linger.
* NEWS: Mention this.
---

diff --git a/NEWS b/NEWS
index 70f9fa2f..4cb22a3f 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,7 @@ Noteworthy changes in release ?.?? (????-??-??)
 
 * Improvements
   * Enhanced decoding of optlen argument of getsockopt syscall.
+  * Enhanced decoding of SO_LINGER option of getsockopt and setsockopt syscalls.
 
 Noteworthy changes in release 4.18 (2017-07-05)
 ===============================================
diff --git a/net.c b/net.c
index 5e20abc6..58a1bbf3 100644
--- a/net.c
+++ b/net.c
@@ -489,8 +489,8 @@ print_sockopt_fd_level_name(struct tcb *tcp, int fd, unsigned int level,
 }
 
 static void
-print_linger(struct tcb *const tcp, const kernel_ulong_t addr,
-	     const unsigned int len)
+print_set_linger(struct tcb *const tcp, const kernel_ulong_t addr,
+		 const unsigned int len)
 {
 	struct linger linger;
 
@@ -505,6 +505,32 @@ print_linger(struct tcb *const tcp, const kernel_ulong_t addr,
 	tprints("}");
 }
 
+static void
+print_get_linger(struct tcb *const tcp, const kernel_ulong_t addr,
+		 unsigned int len)
+{
+	struct linger linger;
+
+	if (len < sizeof(linger)) {
+		if (len != sizeof(linger.l_onoff)) {
+			printstr_ex(tcp, addr, len, QUOTE_FORCE_HEX);
+			return;
+		}
+	} else {
+		len = sizeof(linger);
+	}
+
+	if (umoven(tcp, addr, len, &linger) < 0) {
+		printaddr(addr);
+		return;
+	}
+
+	PRINT_FIELD_D("{", linger, l_onoff);
+	if (len == sizeof(linger))
+		PRINT_FIELD_D(", ", linger, l_linger);
+	tprints("}");
+}
+
 #ifdef SO_PEERCRED
 static void
 print_ucred(struct tcb *const tcp, const kernel_ulong_t addr, const int len)
@@ -573,7 +599,7 @@ print_getsockopt(struct tcb *const tcp, const unsigned int level,
 	case SOL_SOCKET:
 		switch (name) {
 		case SO_LINGER:
-			print_linger(tcp, addr, len);
+			print_get_linger(tcp, addr, len);
 			return;
 #ifdef SO_PEERCRED
 		case SO_PEERCRED:
@@ -771,7 +797,7 @@ print_setsockopt(struct tcb *const tcp, const unsigned int level,
 	case SOL_SOCKET:
 		switch (name) {
 		case SO_LINGER:
-			print_linger(tcp, addr, len);
+			print_set_linger(tcp, addr, len);
 			return;
 		}
 		break;