[LTP] [PATCH] syscalls/mmap17.c: Add new regression test

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2018/02/02 18:20, Jan Stancek wrote:
>
> ----- Original Message -----
>> We add a regression test to check if mmap() can't map invalid physical
>> addresses.  If mmap() maps /dev/mem offsets outside of the addressable
>> limits of a system, setting reserved bits corrupts the page table and
>> triggers a kernel crash.
>>
>> The kernel bug has been fixed by:
>> 'commit ce56a86 ("x86/mm: Limit mmap() of /dev/mem to valid physical
>> addresses")'
>>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
>> ---
>>   runtest/syscalls                        |  1 +
>>   testcases/kernel/syscalls/.gitignore    |  1 +
>>   testcases/kernel/syscalls/mmap/mmap17.c | 81
>>   +++++++++++++++++++++++++++++++++
>>   3 files changed, 83 insertions(+)
>>   create mode 100644 testcases/kernel/syscalls/mmap/mmap17.c
>>
>> diff --git a/runtest/syscalls b/runtest/syscalls
>> index 2a4fad0..4342f03 100644
>> --- a/runtest/syscalls
>> +++ b/runtest/syscalls
>> @@ -641,6 +641,7 @@ mmap14 mmap14
>>   #mmap11 mmap11 -i 30000
>>   mmap15 mmap15
>>   mmap16 mmap16
>> +mmap17 mmap17
>>
>>   modify_ldt01 modify_ldt01
>>   modify_ldt02 modify_ldt02
>> diff --git a/testcases/kernel/syscalls/.gitignore
>> b/testcases/kernel/syscalls/.gitignore
>> index 67211ca..6a8560a 100644
>> --- a/testcases/kernel/syscalls/.gitignore
>> +++ b/testcases/kernel/syscalls/.gitignore
>> @@ -584,6 +584,7 @@
>>   /mmap/mmap14
>>   /mmap/mmap15
>>   /mmap/mmap16
>> +/mmap/mmap17
>>   /modify_ldt/modify_ldt01
>>   /modify_ldt/modify_ldt02
>>   /modify_ldt/modify_ldt03
>> diff --git a/testcases/kernel/syscalls/mmap/mmap17.c
>> b/testcases/kernel/syscalls/mmap/mmap17.c
>> new file mode 100644
>> index 0000000..b83050f
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/mmap/mmap17.c
>> @@ -0,0 +1,81 @@
>> +/*
>> + * Copyright (c) 2018 FUJITSU LIMITED. All rights reserved.
>> + * Author: Xiao Yang<yangx.jy@cn.fujitsu.com>
>> + *
>> + * This program is free software;  you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY;  without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
>> + * the GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License along
>> + * with this program; if not, see<http://www.gnu.org/licenses/>.
>> + */
>> +
>> +/*
>> + * Description:
>> + * A regression test to check if mmap() can't map invalid physical
>> addresses.
>> + * If mmap() maps /dev/mem offsets outside of the addressable limits of a
>> + * system, setting reserved bits corrupts the page table and triggers a
>> kernel
>> + * crash.
>> + *
>> + * The kernel bug has been fixed by:
>> + * 'commit ce56a86 ("x86/mm: Limit mmap() of /dev/mem to valid physical
>> addresses")'
>> + */
>> +
>> +#include<errno.h>
>> +#include<unistd.h>
>> +#include<sys/mman.h>
>> +
>> +#include "tst_test.h"
>> +
>> +#define MEM_PATH	"/dev/mem"
>> +#define CPUINFO_PATH	"/proc/cpuinfo"
>> +
>> +static int fd;
>> +static int phy_addr_bits;
>> +
>> +static void verify_mmap(void)
>> +{
>> +	char *addr;
>> +
>> +	addr = mmap(NULL, 1, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
>> +		    1ULL<<phy_addr_bits);
>> +	if (addr == MAP_FAILED) {
>> +		tst_res(TPASS | TERRNO,
>> +			"Refused to map invalid physical address");
>> +		return;
>> +	}
>> +
>> +	addr[0] = 'a';
>> +	SAFE_MUNMAP(addr, 1);
>> +	tst_res(TFAIL, "Mapped and set invalid physical address successfully");
>> +}
>> +
>> +static void setup(void)
>> +{
>> +	if (access(MEM_PATH, F_OK))
>> +		tst_brk(TCONF, "%s didn't exist", MEM_PATH);
>> +
>> +	fd = SAFE_OPEN(MEM_PATH, O_RDWR | O_SYNC);
>> +
>> +	SAFE_FILE_LINES_SCANF(CPUINFO_PATH, "address sizes\t: %d",
>> +			&phy_addr_bits);
> This looks like a problem for architectures other than x86:
>
> $ grep -l "address sizes" -r arch/
> arch/sh/kernel/cpu/proc.c
> arch/x86/kernel/cpu/proc.c
> arch/x86/kernel/umip.c
> arch/x86/lib/insn-eval.c
Hi Jan,

I tried to find a generic way to get physical address bits from all architectures, but failed.
Do you know how to get physical address bits in generic way?

If we don't have a better way, can we just test the bug which is fixed for x86 on x86 architecture?

Thanks,
Xiao Yang

> Regards,
> Jan
>
>> +}
>> +
>> +static void cleanup(void)
>> +{
>> +	if (fd>  0)
>> +		SAFE_CLOSE(fd);
>> +}
>> +
>> +static struct tst_test test = {
>> +	.needs_root = 1,
>> +	.setup = setup,
>> +	.cleanup = cleanup,
>> +	.test_all = verify_mmap,
>> +};
>> --
>> 1.8.3.1
>>
>>
>>
>>
>> --
>> Mailing list info: https://lists.linux.it/listinfo/ltp
>>
>
> .
>