From 1804dc6e145f3f24a8c94deddfc0a986d380a27f Mon Sep 17 00:00:00 2001
From: Clement Calmels <cboulte@gmail.com>
Date: Wed, 20 Aug 2008 14:09:00 -0700
Subject: /proc/self/maps doesn't display the real file offset

This addresses

	http://bugzilla.kernel.org/show_bug.cgi?id=11318

In function show_map (file: fs/proc/task_mmu.c), if vma->vm_pgoff > 2^20
than (vma->vm_pgoff << PAGE_SIZE) is greater than 2^32 (with PAGE_SIZE
equal to 4096 (i.e.  2^12).  The next seq_printf use an unsigned long for
the conversion of (vma->vm_pgoff << PAGE_SIZE), as a result the offset
value displayed in /proc/self/maps is truncated if the page offset is
greater than 2^20.

A test that shows this issue:

#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

#define PAGE_SIZE (getpagesize())

#if __i386__
#   define U64_STR "%llx"
#elif __x86_64
#   define U64_STR "%lx"
#else
#   error "Architecture Unsupported"
#endif

int main(int argc, char *argv[])
{
	int fd;
	char *addr;
	off64_t offset = 0x10000000;
	char *filename = "/dev/zero";

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
		perror("open");
		return 1;
	}

	offset *= 0x10;
	printf("offset = " U64_STR "\n", offset);

	addr = (char*)mmap64(NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd,
			     offset);
	if ((void*)addr == MAP_FAILED) {
		perror("mmap64");
		return 1;
	}

	{
		FILE *fmaps;
		char *line = NULL;
		size_t len = 0;
		ssize_t read;
		size_t filename_len = strlen(filename);

		fmaps = fopen("/proc/self/maps", "r");
		if (!fmaps) {
			perror("fopen");
			return 1;
		}
		while ((read = getline(&line, &len, fmaps)) != -1) {
			if ((read > filename_len + 1)
			    && (strncmp(&line[read - filename_len - 1], filename, filename_len) == 0))
				printf("%s", line);
		}

		if (line)
			free(line);

		fclose(fmaps);
	}

	close(fd);
	return 0;
}

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Clement Calmels <cboulte@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/proc/task_mmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'fs/proc/task_mmu.c')

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 7546a918f790..73d1891ee625 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -219,14 +219,14 @@ static int show_map(struct seq_file *m, void *v)
 		ino = inode->i_ino;
 	}
 
-	seq_printf(m, "%08lx-%08lx %c%c%c%c %08lx %02x:%02x %lu %n",
+	seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
 			vma->vm_start,
 			vma->vm_end,
 			flags & VM_READ ? 'r' : '-',
 			flags & VM_WRITE ? 'w' : '-',
 			flags & VM_EXEC ? 'x' : '-',
 			flags & VM_MAYSHARE ? 's' : 'p',
-			vma->vm_pgoff << PAGE_SHIFT,
+			((loff_t)vma->vm_pgoff) << PAGE_SHIFT,
 			MAJOR(dev), MINOR(dev), ino, &len);
 
 	/*
-- 
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