From: Dmitry V. Levin <ldv@altlinux.org>
Date: Fri, 1 Apr 2016 15:31:23 +0000 (+0000)
Subject: Consistently handle unsigned arguments of mmap* and remap_file_pages
X-Git-Tag: v4.12~465
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3ae8690d8eb597fe05dc0a2e746b2e6a83926479;p=strace

Consistently handle unsigned arguments of mmap* and remap_file_pages

Explicitly declare first 4 arguments of mmap* and all remap_file_pages
arguments as unsigned to avoid potential sign extension issues.

* mem.c (print_mmap, SYS_FUNC(remap_file_pages)): Assign syscall
arguments to local variables of appropriate types.
---

diff --git a/mem.c b/mem.c
index 28b49c97..53793e6d 100644
--- a/mem.c
+++ b/mem.c
@@ -57,24 +57,24 @@ SYS_FUNC(brk)
 static void
 print_mmap(struct tcb *tcp, long *u_arg, unsigned long long offset)
 {
-	/* addr */
-	printaddr(u_arg[0]);
-	/* len */
-	tprintf(", %lu, ", u_arg[1]);
-	/* prot */
-	printflags(mmap_prot, u_arg[2], "PROT_???");
+	const unsigned long addr = u_arg[0];
+	const unsigned long len = u_arg[1];
+	const unsigned long prot = u_arg[2];
+	const unsigned long flags = u_arg[3];
+	const int fd = u_arg[4];
+
+	printaddr(addr);
+	tprintf(", %lu, ", len);
+	printflags(mmap_prot, prot, "PROT_???");
 	tprints(", ");
-	/* flags */
 #ifdef MAP_TYPE
-	printxval(mmap_flags, u_arg[3] & MAP_TYPE, "MAP_???");
-	addflags(mmap_flags, u_arg[3] & ~MAP_TYPE);
+	printxval(mmap_flags, flags & MAP_TYPE, "MAP_???");
+	addflags(mmap_flags, flags & ~MAP_TYPE);
 #else
-	printflags(mmap_flags, u_arg[3], "MAP_???");
+	printflags(mmap_flags, flags, "MAP_???");
 #endif
 	tprints(", ");
-	/* fd */
-	printfd(tcp, u_arg[4]);
-	/* offset */
+	printfd(tcp, fd);
 	tprintf(", %#llx", offset);
 }
 
@@ -301,15 +301,21 @@ SYS_FUNC(getpagesize)
 
 SYS_FUNC(remap_file_pages)
 {
-	printaddr(tcp->u_arg[0]);
-	tprintf(", %lu, ", tcp->u_arg[1]);
-	printflags(mmap_prot, tcp->u_arg[2], "PROT_???");
-	tprintf(", %lu, ", tcp->u_arg[3]);
+	const unsigned long addr = tcp->u_arg[0];
+	const unsigned long size = tcp->u_arg[1];
+	const unsigned long prot = tcp->u_arg[2];
+	const unsigned long pgoff = tcp->u_arg[3];
+	const unsigned long flags = tcp->u_arg[4];
+
+	printaddr(addr);
+	tprintf(", %lu, ", size);
+	printflags(mmap_prot, prot, "PROT_???");
+	tprintf(", %lu, ", pgoff);
 #ifdef MAP_TYPE
-	printxval(mmap_flags, tcp->u_arg[4] & MAP_TYPE, "MAP_???");
-	addflags(mmap_flags, tcp->u_arg[4] & ~MAP_TYPE);
+	printxval(mmap_flags, flags & MAP_TYPE, "MAP_???");
+	addflags(mmap_flags, flags & ~MAP_TYPE);
 #else
-	printflags(mmap_flags, tcp->u_arg[4], "MAP_???");
+	printflags(mmap_flags, flags, "MAP_???");
 #endif
 
 	return RVAL_DECODED;