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linux-2.6/fs/proc
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Clement Calmels 1804dc6e14 /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>
 		2008-08-20 15:40:30 -07:00
..
Kconfig proc: move Kconfig to fs/proc/Kconfig 2008-07-25 10:53:45 -07:00
Makefile [NET]: Make /proc/net per network namespace 2007-10-10 16:49:06 -07:00
array.c tracehook: tracehook_tracer_task 2008-07-26 12:00:08 -07:00
base.c proc: fix warnings 2008-08-05 14:33:50 -07:00
generic.c [PATCH 2/2] proc: switch inode number allocation to IDA 2008-08-01 11:25:28 -04:00
inode-alloc.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
inode.c [PATCH] sanitize proc_sysctl 2008-07-26 20:53:12 -04:00
internal.h proc: always do ->release 2008-07-25 10:53:44 -07:00
kcore.c elf: use ELF_CORE_EFLAGS for kcore ELF header flags 2008-07-25 10:53:42 -07:00
kmsg.c move proc_kmsg_operations to fs/proc/internal.h 2008-07-25 10:53:44 -07:00
mmu.c fs/proc/mmu.c: headers butchery 2007-10-17 08:42:48 -07:00
nommu.c /proc/self/maps doesn't display the real file offset 2008-08-20 15:40:30 -07:00
proc_devtree.c [POWERPC] Make struct property's value a void * 2007-04-13 03:55:18 +10:00
proc_misc.c vmallocinfo: add NUMA information 2008-07-24 10:47:17 -07:00
proc_net.c netns: make get_proc_net() static 2008-07-22 14:19:19 -07:00
proc_sysctl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
proc_tty.c tty: Ldisc revamp 2008-07-20 17:12:34 -07:00
root.c proc: introduce proc_create_data to setup de->data 2008-04-29 08:06:20 -07:00
task_mmu.c /proc/self/maps doesn't display the real file offset 2008-08-20 15:40:30 -07:00
task_nommu.c Security: split proc ptrace checking into read vs. attach 2008-07-14 15:01:47 +10:00
vmcore.c aout: remove unnecessary inclusions of {asm, linux}/a.out.h 2008-02-08 09:22:30 -08:00