set-anon-vma-name-test.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * This test covers the anonymous VMA naming functionality through prctl calls
  4 */
  5
  6#include <errno.h>
  7#include <sys/prctl.h>
  8#include <stdio.h>
  9#include <stdlib.h>
 10#include <sys/mman.h>
 11#include <string.h>
 12
 13#include "kselftest_harness.h"
 14
 15#define AREA_SIZE 1024
 16
 17#define GOOD_NAME "goodname"
 18#define BAD_NAME "badname\1"
 19
 20#ifndef PR_SET_VMA
 21#define PR_SET_VMA 0x53564d41
 22#define PR_SET_VMA_ANON_NAME 0
 23#endif
 24
 25
 26int rename_vma(unsigned long addr, unsigned long size, char *name)
 27{
 28	int res;
 29
 30	res = prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, addr, size, name);
 31	if (res < 0)
 32		return -errno;
 33	return res;
 34}
 35
 36int was_renaming_successful(char *target_name, unsigned long ptr)
 37{
 38	FILE *maps_file;
 39
 40	char line_buf[512], name[128], mode[8];
 41	unsigned long start_addr, end_addr, offset;
 42	unsigned int major_id, minor_id, node_id;
 43
 44	char target_buf[128];
 45	int res = 0, sscanf_res;
 46
 47	// The entry name in maps will be in format [anon:<target_name>]
 48	sprintf(target_buf, "[anon:%s]", target_name);
 49	maps_file = fopen("/proc/self/maps", "r");
 50	if (!maps_file) {
 51		printf("## /proc/self/maps file opening error\n");
 52		return 0;
 53	}
 54
 55	// Parse the maps file to find the entry we renamed
 56	while (fgets(line_buf, sizeof(line_buf), maps_file)) {
 57		sscanf_res = sscanf(line_buf, "%lx-%lx %7s %lx %u:%u %u %s", &start_addr,
 58					&end_addr, mode, &offset, &major_id,
 59					&minor_id, &node_id, name);
 60		if (sscanf_res == EOF) {
 61			res = 0;
 62			printf("## EOF while parsing the maps file\n");
 63			break;
 64		}
 65		if (!strcmp(name, target_buf) && start_addr == ptr) {
 66			res = 1;
 67			break;
 68		}
 69	}
 70	fclose(maps_file);
 71	return res;
 72}
 73
 74FIXTURE(vma) {
 75	void *ptr_anon, *ptr_not_anon;
 76};
 77
 78FIXTURE_SETUP(vma) {
 79	self->ptr_anon = mmap(NULL, AREA_SIZE, PROT_READ | PROT_WRITE,
 80					MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
 81	ASSERT_NE(self->ptr_anon, NULL);
 82	self->ptr_not_anon = mmap(NULL, AREA_SIZE, PROT_READ | PROT_WRITE,
 83					MAP_PRIVATE, 0, 0);
 84	ASSERT_NE(self->ptr_not_anon, NULL);
 85}
 86
 87FIXTURE_TEARDOWN(vma) {
 88	munmap(self->ptr_anon, AREA_SIZE);
 89	munmap(self->ptr_not_anon, AREA_SIZE);
 90}
 91
 92TEST_F(vma, renaming) {
 93	TH_LOG("Try to rename the VMA with correct parameters");
 94	EXPECT_GE(rename_vma((unsigned long)self->ptr_anon, AREA_SIZE, GOOD_NAME), 0);
 95	EXPECT_TRUE(was_renaming_successful(GOOD_NAME, (unsigned long)self->ptr_anon));
 96
 97	TH_LOG("Try to pass invalid name (with non-printable character \\1) to rename the VMA");
 98	EXPECT_EQ(rename_vma((unsigned long)self->ptr_anon, AREA_SIZE, BAD_NAME), -EINVAL);
 99
100	TH_LOG("Try to rename non-anonymous VMA");
101	EXPECT_EQ(rename_vma((unsigned long) self->ptr_not_anon, AREA_SIZE, GOOD_NAME), -EINVAL);
102}
103
104TEST_HARNESS_MAIN