[LTP] [PATCH v4 1/1] mount03: Convert to new API

[xuyang2018.jy@fujitsu.com]

Hi Richard, Petr

> 
> "xuyang2018.jy@fujitsu.com" <xuyang2018.jy@fujitsu.com> writes:
> 
>> Hi Petr
>>
>>> Hi all,
>>>
>>> when running in loop, I sometimes still get error:
>>>
>>> i=0; while true; do i=$((i+1)); echo "== $i =="; ./mount03  || break; done
>>> ...
>>> === 100 ===
>>> ...
>>> tst_device.c:434: TINFO: No device is mounted at mntpoint
>>> tst_test.c:1599: TINFO: Testing on ext4
>>> tst_test.c:1065: TINFO: Formatting /dev/loop0 with ext4 opts='' extra opts=''
>>> mke2fs 1.46.5 (30-Dec-2021)
>>> mount03.c:150: TINFO: Testing flag MS_RDONLY
>>> mount03.c:48: TPASS: otfd = open(file, O_CREAT | O_RDWR, 0700) : EROFS (30)
>>> mount03.c:150: TINFO: Testing flag MS_NODEV
>>> mount03.c:153: TFAIL: mount(tst_device->dev, MNTPOINT, tst_device->fs_type, tc->flag, NULL) failed: EINVAL (22)
>>> mount03.c:150: TINFO: Testing flag MS_NOEXEC
>>> mount03.c:153: TFAIL: mount(tst_device->dev, MNTPOINT, tst_device->fs_type, tc->flag, NULL) failed: EINVAL (22)
>>> mount03.c:150: TINFO: Testing flag MS_RDONLY
>>> mount03.c:153: TFAIL: mount(tst_device->dev, MNTPOINT, tst_device->fs_type, tc->flag, NULL) failed: EINVAL (22)
>>> mount03.c:150: TINFO: Testing flag MS_NOSUID
>>> mount03.c:153: TFAIL: mount(tst_device->dev, MNTPOINT, tst_device->fs_type, tc->flag, NULL) failed: EINVAL (22)
>>> mount03.c:150: TINFO: Testing flag MS_NOATIME
>>> mount03.c:111: TPASS: st.st_atime == atime (1661183501)
>>
>> I also meet nosuid work not as expected.
>>
>> st_test.c:1599: TINFO: Testing on ext4
>> tst_test.c:1064: TINFO: Formatting /dev/loop0 with ext4 opts='' extra
>> opts=''
>> mke2fs 1.46.5 (30-Dec-2021)
>> mount03.c:151: TINFO: Testing flag MS_RDONLY
>> mount03.c:48: TPASS: otfd = open(file, O_CREAT | O_RDWR, 0700) : EROFS (30)
>> mount03.c:151: TINFO: Testing flag MS_NODEV
>> mount03.c:55: TPASS: otfd = open(file, O_RDWR, 0700) : EACCES (13)
>> mount03.c:151: TINFO: Testing flag MS_NOEXEC
>> mount03.c:63: TPASS: execlp(file, basename(file), NULL) : EACCES (13)
>> mount03.c:151: TINFO: Testing flag MS_RDONLY
>> mount03.c:70: TPASS: otfd = open(file, O_CREAT | O_RDWR, 0700) returned fd 3
>> mount03.c:151: TINFO: Testing flag MS_NOSUID
>> mount03_suid_child.c:22: TFAIL: setreuid(getuid(), 0) succeeded
>> mount03.c:151: TINFO: Testing flag MS_NOATIME
>> mount03.c:112: TPASS: st.st_atime == atime (1661280863)
>> tst_device.c:434: TINFO: No device is mounted at mntpoint
>>
> 
> I added some more debug info:
> 
> @@ -86,7 +89,20 @@ static void test_nosuid(void)
>   		if (st.st_mode != SUID_MODE)
>   			SAFE_CHMOD(BIN_PATH, SUID_MODE);
>   
> -		SAFE_SETREUID(nobody_uid, nobody_uid);
> +		tst_res(TINFO, "dev %d:%d, rdev: %d:%d",
> +			major(st.st_dev), minor(st.st_dev), major(st.st_rdev), minor(st.st_rdev));
> +		SAFE_SETRESGID(nobody_gid, nobody_gid, nobody_gid);
> +		SAFE_SETRESUID(nobody_uid, nobody_uid, nobody_uid);
> +
> +		uid_t uid, gid, euid, egid, suid, sgid;
> +
> +		getresuid(&uid, &euid, &suid);
> +		getresgid(&gid, &egid, &sgid);
> +		tst_res(TINFO, "uid: %d, gid: %d, euid: %d, egid: %d, suid: %d, sgid: %d",
> +			uid, gid, euid, egid, suid, sgid);
> +
> +		tst_system("pwd");
> +		tst_system("ls -l " MNTPOINT);
>   		SAFE_EXECL(BIN_PATH, BIN_PATH, NULL);
>   		tst_brk(TFAIL | TTERRNO, "Failed to execute %s", BIN_PATH);
> 
> and in the child
> 
>   int main(void)
>   {
> +	uid_t uid, gid, euid, egid, suid, sgid;
>   	tst_reinit();
>   
> +	getresuid(&uid, &euid, &suid);
> +	getresgid(&gid, &egid, &sgid);
> +	tst_res(TINFO, "uid: %d, gid: %d, euid: %d, egid: %d, suid: %d, sgid: %d",
> +		uid, gid, euid, egid, suid, sgid);
> +
>   	TST_EXP_FAIL(setreuid(getuid(), 0), EPERM);
>   
> 
> This shows that BIN_PATH is being accessed from the wrong device AFAICT
> 
> mount03.c:166: TINFO: Testing flag MS_NOSUID
> 
> ...
> 
> 30 1 0:26 / /tmp rw,relatime - tmpfs ltp rw,size=512000k,inode64
> 31 30 0:27 / /tmp/mouLkSN2v/mntpoint rw,nosuid,relatime - tmpfs /dev/loop0 rw,inode64
> mount03.c:92: TINFO: dev 0:26, rdev: 0:0
> mount03.c:101: TINFO: uid: 65534, gid: 65534, euid: 65534, egid: 65534, suid: 65534, sgid: 65534
> /tmp/mouLkSN2v
> total 688
> -r-s--x--x 1 root 0 702952 Oct 13 11:29 mount03_suid_child
> mount03_suid_child.c:25: TINFO: uid: 65534, gid: 65534, euid: 0, egid: 65534, suid: 0, sgid: 65534
> mount03_suid_child.c:28: TFAIL: setreuid(getuid(), 0) succeeded
> 
> The device should be 0:27 not 0:26.
> 
> Indeed if I remove SAFE_CHMOD then the euid and suid are set to
> nobody. Also if I mount /tmp as nosuid then the test passes. Possibly we
> need to use absoute paths to ensure we are going through the mount
> point.

I use statfs struct f_flags member to debug, then found the mounted 
filesystem doesn't have nosuid flag.

It seems parent has umounted this dev and so child doesn't have nosuid 
flag, so this case failed.

--- a/testcases/kernel/syscalls/mount/mount03.c
+++ b/testcases/kernel/syscalls/mount/mount03.c
@@ -90,6 +90,7 @@ static void test_nosuid(void)
                 SAFE_EXECL(BIN_PATH, BIN_PATH, NULL);
                 tst_brk(TFAIL | TTERRNO, "Failed to execute %s", BIN_PATH);
         }
+       tst_reap_children();
  }


After this change, this case can pass when I run with -i 10.


Best Regards
Yang Xu
>