mount: rm ForceMount #1
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Since this is a new library, we are free to remove the deprecated functions. Fortunately, there's only one. Signed-off-by: Kir Kolyshkin <[email protected]>
AkihiroSuda
approved these changes
Mar 15, 2020
justincormack
approved these changes
Mar 15, 2020
kolyshkin
referenced
this pull request
in kolyshkin/sys
Mar 16, 2020
TIL older kernels (presumably < 5.1) has a bug of not showing
the "source" field in /proc/self/mountinfo in case an empty
string was passed as the source argument to mount() syscall.
My best guess is it was fixed by the kernel commit 8f2918898eb5f
("new helpers: vfs_create_mount(), fc_mount()", Nov 4 2018) which
is v5.1-rc1~12^2~37, i.e. kernel 5.1 should be the one with the fix.
I was able to reproduce it on a machine with an old kernel:
```console
[kir@micros ~]$ cat a.c
#include <sys/mount.h>
#include <stdio.h>
int main(void) {
int r;
r = mount("", "/tmp/bb", "tmpfs", MS_MGC_VAL, (void*)0);
if (r != 0) {
perror("mount");
return 1;
}
return 0;
}
[kir@micros ~]$ gcc -Wall -o a a.c
[kir@micros ~]$ mkdir /tmp/bb
[kir@micros ~]$ ./a; echo $?
mount: Operation not permitted
1
[kir@micros ~]$ sudo ./a; echo $?
0
[kir@micros ~]$ grep -F /tmp/bb /proc/self/mountinfo
279 23 0:108 / /tmp/bb rw,relatime - tmpfs rw
[kir@micros ~]$ # notice the two spaces ^^^^^ here
[kir@micros ~]$ uname -a
Linux micros 2.6.32-042stab133.2 #1 SMP Mon Aug 27 21:07:08 MSK 2018 x86_64 x86_64 x86_64 GNU/Linux
```
The most interesting thing is this package is not affected by the bug,
working as expected, since strings.Split by a space gives an empty
element in case of two spaces.
Nevertheless, it makes sense to add a test case for it.
Signed-off-by: Kir Kolyshkin <[email protected]>
cpuguy83
pushed a commit
that referenced
this pull request
Mar 19, 2020
TIL older kernels (presumably < 5.1) has a bug of not showing
the "source" field in /proc/self/mountinfo in case an empty
string was passed as the source argument to mount() syscall.
My best guess is it was fixed by the kernel commit 8f2918898eb5f
("new helpers: vfs_create_mount(), fc_mount()", Nov 4 2018) which
is v5.1-rc1~12^2~37, i.e. kernel 5.1 should be the one with the fix.
I was able to reproduce it on a machine with an old kernel:
```console
[kir@micros ~]$ cat a.c
#include <sys/mount.h>
#include <stdio.h>
int main(void) {
int r;
r = mount("", "/tmp/bb", "tmpfs", MS_MGC_VAL, (void*)0);
if (r != 0) {
perror("mount");
return 1;
}
return 0;
}
[kir@micros ~]$ gcc -Wall -o a a.c
[kir@micros ~]$ mkdir /tmp/bb
[kir@micros ~]$ ./a; echo $?
mount: Operation not permitted
1
[kir@micros ~]$ sudo ./a; echo $?
0
[kir@micros ~]$ grep -F /tmp/bb /proc/self/mountinfo
279 23 0:108 / /tmp/bb rw,relatime - tmpfs rw
[kir@micros ~]$ # notice the two spaces ^^^^^ here
[kir@micros ~]$ uname -a
Linux micros 2.6.32-042stab133.2 #1 SMP Mon Aug 27 21:07:08 MSK 2018 x86_64 x86_64 x86_64 GNU/Linux
```
The most interesting thing is this package is not affected by the bug,
working as expected, since strings.Split by a space gives an empty
element in case of two spaces.
Nevertheless, it makes sense to add a test case for it.
Signed-off-by: Kir Kolyshkin <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Since this is a new library, we are free to remove the deprecated
functions. Fortunately, there's only one.