From 43946df838529fb810cc203411defdadefb242db Mon Sep 17 00:00:00 2001
From: Eugene Syromyatnikov <evgsyr@gmail.com>
Date: Thu, 27 Sep 2018 07:12:18 +0200
Subject: [PATCH] syslog: fix argument printing

* syslog.c (SYS_FUNC(syslog)): Store conversion to int of tcp->u_arg[2]
in len; print address using printaddr64 (as syslog doesn't use compat
for x32), and third argument as int (as it has this type in the syscall
handler).
* tests/syslog.c: Add checks.
---
 syslog.c       |  9 ++++----
 tests/syslog.c | 57 ++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/syslog.c b/syslog.c
index 92d68f2a..1297f7f1 100644
--- a/syslog.c
+++ b/syslog.c
@@ -13,6 +13,7 @@
 SYS_FUNC(syslog)
 {
 	int type = tcp->u_arg[0];
+	int len = tcp->u_arg[2];
 
 	if (entering(tcp)) {
 		/* type */
@@ -41,8 +42,8 @@ SYS_FUNC(syslog)
 		break;
 	default:
 		tprints(", ");
-		printaddr(tcp->u_arg[1]);
-		tprintf(", %" PRI_klu, tcp->u_arg[2]);
+		printaddr64(tcp->u_arg[1]);
+		tprintf(", %d", len);
 		return RVAL_DECODED;
 	}
 
@@ -50,11 +51,11 @@ SYS_FUNC(syslog)
 
 	/* bufp */
 	if (syserror(tcp))
-		printaddr(tcp->u_arg[1]);
+		printaddr64(tcp->u_arg[1]);
 	else
 		printstrn(tcp, tcp->u_arg[1], tcp->u_rval);
 	/* len */
-	tprintf(", %d", (int) tcp->u_arg[2]);
+	tprintf(", %d", len);
 
 	return 0;
 }
diff --git a/tests/syslog.c b/tests/syslog.c
index 151880d1..a3c66e8d 100644
--- a/tests/syslog.c
+++ b/tests/syslog.c
@@ -13,8 +13,26 @@
 # include <stdio.h>
 # include <unistd.h>
 
-# define SYSLOG_ACTION_READ 2
-# define SYSLOG_ACTION_SIZE_BUFFER 10
+bool
+valid_cmd(int cmd)
+{
+	return cmd >= 0 && cmd <= 10;
+}
+
+void
+printstr(const char *s, int cmd, long size)
+{
+	if (size < 0 || !valid_cmd(cmd))
+		printf("%p", s);
+	else if (size == 0)
+		printf("\"\"");
+	else if (size <= DEFAULT_STRLEN)
+		print_quoted_memory(s, size);
+	else {
+		print_quoted_memory(s, DEFAULT_STRLEN);
+		printf("...");
+	}
+}
 
 int
 main(void)
@@ -31,19 +49,46 @@ main(void)
 		{ 9,  "9 /* SYSLOG_ACTION_SIZE_UNREAD */" },
 		{ 10, "10 /* SYSLOG_ACTION_SIZE_BUFFER */" },
 	};
+	static const struct cmd_str two_args[] = {
+		{ 0xfeedbeef, "-17973521 /* SYSLOG_ACTION_??? */" },
+		{ -1U, "-1 /* SYSLOG_ACTION_??? */" },
+		{ 2,  "2 /* SYSLOG_ACTION_READ */" },
+		{ 3,  "3 /* SYSLOG_ACTION_READ_ALL */" },
+		{ 4,  "4 /* SYSLOG_ACTION_READ_CLEAR */" },
+		{ 11, "11 /* SYSLOG_ACTION_??? */" },
+		{ (1U << 31) - 1, "2147483647 /* SYSLOG_ACTION_??? */" },
+	};
 	static const kernel_ulong_t high =
 		(kernel_ulong_t) 0xbadc0ded00000000ULL;
-	const long addr = (long) 0xfacefeeddeadbeefULL;
+	const kernel_ulong_t addr = (kernel_ulong_t) 0xfacefeeddeadbeefULL;
 	int rc;
+
 	for (size_t i = 0; i < ARRAY_SIZE(no_args); i++) {
 		rc = syscall(__NR_syslog, high | no_args[i].cmd, addr, -1);
 		printf("syslog(%s) = %s\n",
 		no_args[i].str, sprintrc(rc));
 	}
 
-	rc = syscall(__NR_syslog, SYSLOG_ACTION_READ, addr, -1);
-	printf("syslog(2 /* SYSLOG_ACTION_READ */, %#lx, -1) = %s\n",
-	       addr, sprintrc(rc));
+	for (size_t i = 0; i < ARRAY_SIZE(two_args); i++) {
+		rc = syscall(__NR_syslog, high | two_args[i].cmd, NULL, -1);
+		printf("syslog(%s, NULL, -1) = %s\n",
+		       two_args[i].str, sprintrc(rc));
+
+		rc = syscall(__NR_syslog, high | two_args[i].cmd, addr, -1);
+		printf("syslog(%s, %#llx, -1) = %s\n",
+		       two_args[i].str, (unsigned long long) addr,
+		       sprintrc(rc));
+
+		rc = syscall(__NR_syslog, two_args[i].cmd, addr, 0);
+		printf("syslog(%s, %s, 0) = %s\n",
+		       two_args[i].str,
+		       !rc && valid_cmd(two_args[i].cmd)
+			   && (sizeof(kernel_ulong_t) == sizeof(void *))
+				? "\"\""
+				: (sizeof(addr) == 8) ? "0xfacefeeddeadbeef"
+						      : "0xdeadbeef",
+		       sprintrc(rc));
+	}
 
 	puts("+++ exited with 0 +++");
 	return 0;
-- 
2.40.0