From: Dmitry V. Levin <ldv@altlinux.org>
Date: Fri, 29 Jan 2016 01:51:54 +0000 (+0000)
Subject: Fixed decoding of mincore syscall's last argument
X-Git-Tag: v4.12~614
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=dfea1da0e6361e80b66a9ef7d9e0f35518a7629c;p=strace

Fixed decoding of mincore syscall's last argument

* mem.c (SYS_FUNC(mincore)): Print only those bytes of the vector
that were written by the kernel.
* NEWS: Mention this fix.
* tests/mincore.c: New file.
* tests/mincore.test: New test.
* tests/Makefile.am (check_PROGRAMS): Add mincore.
(TESTS): Add mincore.test.
* tests/.gitignore: Add mincore.
---

diff --git a/NEWS b/NEWS
index a7520d66..b9ed032b 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,7 @@ Noteworthy changes in release ?.?? (????-??-??)
     (addresses Debian bug #485979 and Fedora bug #1298294).
   * Fixed decoding and dumping of readv syscall in case of short read.
   * Fixed dumping of recvmsg and recvmmsg syscalls in case of short read.
+  * Fixed decoding of mincore syscall's last argument.
 
 Noteworthy changes in release 4.11 (2015-12-21)
 ===============================================
diff --git a/mem.c b/mem.c
index 37c7daba..28b49c97 100644
--- a/mem.c
+++ b/mem.c
@@ -264,15 +264,18 @@ SYS_FUNC(mincore)
 		printaddr(tcp->u_arg[0]);
 		tprintf(", %lu, ", tcp->u_arg[1]);
 	} else {
-		unsigned long i, len;
-		char *vec = NULL;
+		const unsigned long page_size = get_pagesize();
+		const unsigned long page_mask = page_size - 1;
+		unsigned long len = tcp->u_arg[1];
+		unsigned char *vec = NULL;
 
-		len = tcp->u_arg[1];
+		len = len / page_size + (len & page_mask ? 1 : 0);
 		if (syserror(tcp) || !verbose(tcp) ||
 		    !tcp->u_arg[2] || !(vec = malloc(len)) ||
 		    umoven(tcp, tcp->u_arg[2], len, vec) < 0)
 			printaddr(tcp->u_arg[2]);
 		else {
+			unsigned long i;
 			tprints("[");
 			for (i = 0; i < len; i++) {
 				if (abbrev(tcp) && i >= max_strlen) {
diff --git a/tests/.gitignore b/tests/.gitignore
index 207a9b2e..10214d35 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -50,6 +50,7 @@ lstat
 lstat64
 membarrier
 memfd_create
+mincore
 mlock2
 mmap
 mmap64
diff --git a/tests/Makefile.am b/tests/Makefile.am
index f6345836..e31be34e 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -96,6 +96,7 @@ check_PROGRAMS = \
 	lstat64 \
 	membarrier \
 	memfd_create \
+	mincore \
 	mlock2 \
 	mmap \
 	mmap64 \
@@ -235,6 +236,7 @@ TESTS = \
 	lstat64.test \
 	membarrier.test \
 	memfd_create.test \
+	mincore.test \
 	mlock2.test \
 	mmap.test \
 	mmap64.test \
diff --git a/tests/mincore.c b/tests/mincore.c
new file mode 100644
index 00000000..d9cbbd4c
--- /dev/null
+++ b/tests/mincore.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "tests.h"
+#include <stdio.h>
+#include <sys/mman.h>
+
+#define DEFAULT_STRLEN 32
+
+static void
+test_mincore(const unsigned int pages)
+{
+	const size_t size = pages * get_page_size();
+	char *addr = tail_alloc(size);
+	unsigned char *vec = tail_alloc(pages);
+	unsigned int i;
+
+	if (mincore(addr, size, vec))
+		perror_msg_and_skip("mincore");
+	printf("mincore(%p, %zu, [", addr, size);
+	for (i = 0; i < pages; ++i) {
+		if (i >= DEFAULT_STRLEN) {
+			printf("...");
+			break;
+		}
+		printf("%u", vec[i] & 1);
+	}
+	puts("]) = 0");
+}
+
+int main(void)
+{
+	test_mincore(1);
+	test_mincore(2);
+	test_mincore(DEFAULT_STRLEN + 1);
+
+	puts("+++ exited with 0 +++");
+	return 0;
+}
diff --git a/tests/mincore.test b/tests/mincore.test
new file mode 100755
index 00000000..9a6a6865
--- /dev/null
+++ b/tests/mincore.test
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+# Check mincore syscall decoding.
+
+. "${srcdir=.}/init.sh"
+
+run_prog > /dev/null
+OUT="$LOG.out"
+run_strace -a22 -emincore $args > "$OUT"
+match_diff "$LOG" "$OUT"
+rm -f "$OUT"