* [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines
@ 2021-08-03 10:59 Thomas Huth
2021-08-03 10:59 ` [PATCH 1/2] sysctl: introduce new proc handler proc_dobool Thomas Huth
` (4 more replies)
0 siblings, 5 replies; 9+ messages in thread
From: Thomas Huth @ 2021-08-03 10:59 UTC (permalink / raw)
To: linux-kernel, linux-fsdevel, linux-nfs
Cc: J. Bruce Fields, Chuck Lever, Trond Myklebust, Anna Schumaker,
Luis Chamberlain, Kees Cook, Iurii Zaikin, linux-s390, Jia He,
Pan Xinhui
There is an endianess problem with /proc/sys/fs/nfs/nsm_use_hostnames
(which can e.g. be seen on an s390x host) :
# modprobe lockd nsm_use_hostnames=1
# cat /proc/sys/fs/nfs/nsm_use_hostnames
16777216
The nsm_use_hostnames variable is declared as "bool" which is required
for the correct type for the module parameter. However, this does not
work correctly with the entry in the /proc filesystem since this
currently requires "int".
Jia He already provided patches for this problem a couple of years ago,
but apparently they felt through the cracks and never got merged. So
here's a rebased version to finally fix this issue.
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1764075
Jia He (2):
sysctl: introduce new proc handler proc_dobool
lockd: change the proc_handler for nsm_use_hostnames
fs/lockd/svc.c | 2 +-
include/linux/sysctl.h | 2 ++
kernel/sysctl.c | 42 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 45 insertions(+), 1 deletion(-)
--
2.27.0
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] sysctl: introduce new proc handler proc_dobool
2021-08-03 10:59 [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines Thomas Huth
@ 2021-08-03 10:59 ` Thomas Huth
2021-09-16 22:03 ` Kees Cook
2021-08-03 10:59 ` [PATCH 2/2] lockd: change the proc_handler for nsm_use_hostnames Thomas Huth
` (3 subsequent siblings)
4 siblings, 1 reply; 9+ messages in thread
From: Thomas Huth @ 2021-08-03 10:59 UTC (permalink / raw)
To: linux-kernel, linux-fsdevel, linux-nfs
Cc: J. Bruce Fields, Chuck Lever, Trond Myklebust, Anna Schumaker,
Luis Chamberlain, Kees Cook, Iurii Zaikin, linux-s390, Jia He,
Pan Xinhui
From: Jia He <hejianet@gmail.com>
This is to let bool variable could be correctly displayed in
big/little endian sysctl procfs. sizeof(bool) is arch dependent,
proc_dobool should work in all arches.
Suggested-by: Pan Xinhui <xinhui@linux.vnet.ibm.com>
Signed-off-by: Jia He <hejianet@gmail.com>
[thuth: rebased the patch to the current kernel version]
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
include/linux/sysctl.h | 2 ++
kernel/sysctl.c | 42 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 44 insertions(+)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index d99ca99837de..1fa2b69c6fc3 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -48,6 +48,8 @@ typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
size_t *lenp, loff_t *ppos);
int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
+int proc_dobool(struct ctl_table *table, int write, void *buffer,
+ size_t *lenp, loff_t *ppos);
int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 272f4a272f8c..25e49b4d8049 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -536,6 +536,21 @@ static void proc_put_char(void **buf, size_t *size, char c)
}
}
+static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp,
+ int *valp,
+ int write, void *data)
+{
+ if (write) {
+ *(bool *)valp = *lvalp;
+ } else {
+ int val = *(bool *)valp;
+
+ *lvalp = (unsigned long)val;
+ *negp = false;
+ }
+ return 0;
+}
+
static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
@@ -798,6 +813,26 @@ static int do_proc_douintvec(struct ctl_table *table, int write,
buffer, lenp, ppos, conv, data);
}
+/**
+ * proc_dobool - read/write a bool
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * Returns 0 on success.
+ */
+int proc_dobool(struct ctl_table *table, int write, void *buffer,
+ size_t *lenp, loff_t *ppos)
+{
+ return do_proc_dointvec(table, write, buffer, lenp, ppos,
+ do_proc_dobool_conv, NULL);
+}
+
/**
* proc_dointvec - read a vector of integers
* @table: the sysctl table
@@ -1630,6 +1665,12 @@ int proc_dostring(struct ctl_table *table, int write,
return -ENOSYS;
}
+int proc_dobool(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ return -ENOSYS;
+}
+
int proc_dointvec(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
@@ -3425,6 +3466,7 @@ int __init sysctl_init(void)
* No sense putting this after each symbol definition, twice,
* exception granted :-)
*/
+EXPORT_SYMBOL(proc_dobool);
EXPORT_SYMBOL(proc_dointvec);
EXPORT_SYMBOL(proc_douintvec);
EXPORT_SYMBOL(proc_dointvec_jiffies);
--
2.27.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/2] lockd: change the proc_handler for nsm_use_hostnames
2021-08-03 10:59 [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines Thomas Huth
2021-08-03 10:59 ` [PATCH 1/2] sysctl: introduce new proc handler proc_dobool Thomas Huth
@ 2021-08-03 10:59 ` Thomas Huth
2021-09-16 22:05 ` Kees Cook
2021-08-03 14:08 ` [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines J. Bruce Fields
` (2 subsequent siblings)
4 siblings, 1 reply; 9+ messages in thread
From: Thomas Huth @ 2021-08-03 10:59 UTC (permalink / raw)
To: linux-kernel, linux-fsdevel, linux-nfs
Cc: J. Bruce Fields, Chuck Lever, Trond Myklebust, Anna Schumaker,
Luis Chamberlain, Kees Cook, Iurii Zaikin, linux-s390, Jia He,
Pan Xinhui
From: Jia He <hejianet@gmail.com>
nsm_use_hostnames is a module parameter and it will be exported to sysctl
procfs. This is to let user sometimes change it from userspace. But the
minimal unit for sysctl procfs read/write it sizeof(int).
In big endian system, the converting from/to bool to/from int will cause
error for proc items.
This patch use a new proc_handler proc_dobool to fix it.
Signed-off-by: Jia He <hejianet@gmail.com>
Reviewed-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
[thuth: Fix typo in commit message]
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
fs/lockd/svc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 2de048f80eb8..0ab9756ed235 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -584,7 +584,7 @@ static struct ctl_table nlm_sysctls[] = {
.data = &nsm_use_hostnames,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dobool,
},
{
.procname = "nsm_local_state",
--
2.27.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines
2021-08-03 10:59 [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines Thomas Huth
2021-08-03 10:59 ` [PATCH 1/2] sysctl: introduce new proc handler proc_dobool Thomas Huth
2021-08-03 10:59 ` [PATCH 2/2] lockd: change the proc_handler for nsm_use_hostnames Thomas Huth
@ 2021-08-03 14:08 ` J. Bruce Fields
2021-08-03 14:24 ` Chuck Lever III
2021-08-04 2:12 ` Jia He
2021-08-09 17:50 ` Chuck Lever III
4 siblings, 1 reply; 9+ messages in thread
From: J. Bruce Fields @ 2021-08-03 14:08 UTC (permalink / raw)
To: Thomas Huth
Cc: linux-kernel, linux-fsdevel, linux-nfs, Chuck Lever,
Trond Myklebust, Anna Schumaker, Luis Chamberlain, Kees Cook,
Iurii Zaikin, linux-s390, Jia He, Pan Xinhui
Looks good to me. Could Chuck take it with nfsd stuff if somebody could
ACK the sysctl part?
--b.
On Tue, Aug 03, 2021 at 12:59:35PM +0200, Thomas Huth wrote:
> There is an endianess problem with /proc/sys/fs/nfs/nsm_use_hostnames
> (which can e.g. be seen on an s390x host) :
>
> # modprobe lockd nsm_use_hostnames=1
> # cat /proc/sys/fs/nfs/nsm_use_hostnames
> 16777216
>
> The nsm_use_hostnames variable is declared as "bool" which is required
> for the correct type for the module parameter. However, this does not
> work correctly with the entry in the /proc filesystem since this
> currently requires "int".
>
> Jia He already provided patches for this problem a couple of years ago,
> but apparently they felt through the cracks and never got merged. So
> here's a rebased version to finally fix this issue.
>
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1764075
>
> Jia He (2):
> sysctl: introduce new proc handler proc_dobool
> lockd: change the proc_handler for nsm_use_hostnames
>
> fs/lockd/svc.c | 2 +-
> include/linux/sysctl.h | 2 ++
> kernel/sysctl.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 45 insertions(+), 1 deletion(-)
>
> --
> 2.27.0
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines
2021-08-03 14:08 ` [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines J. Bruce Fields
@ 2021-08-03 14:24 ` Chuck Lever III
0 siblings, 0 replies; 9+ messages in thread
From: Chuck Lever III @ 2021-08-03 14:24 UTC (permalink / raw)
To: Bruce Fields
Cc: Thomas Huth, LKML, linux-fsdevel, Linux NFS Mailing List,
Trond Myklebust, Anna Schumaker, Luis Chamberlain, Kees Cook,
Iurii Zaikin, linux-s390, Jia He, Pan Xinhui
Thanks for your review, Bruce. I'll watch for the additional Ack.
> On Aug 3, 2021, at 10:08 AM, J. Bruce Fields <bfields@fieldses.org> wrote:
>
> Looks good to me. Could Chuck take it with nfsd stuff if somebody could
> ACK the sysctl part?
>
> --b.
>
> On Tue, Aug 03, 2021 at 12:59:35PM +0200, Thomas Huth wrote:
>> There is an endianess problem with /proc/sys/fs/nfs/nsm_use_hostnames
>> (which can e.g. be seen on an s390x host) :
>>
>> # modprobe lockd nsm_use_hostnames=1
>> # cat /proc/sys/fs/nfs/nsm_use_hostnames
>> 16777216
>>
>> The nsm_use_hostnames variable is declared as "bool" which is required
>> for the correct type for the module parameter. However, this does not
>> work correctly with the entry in the /proc filesystem since this
>> currently requires "int".
>>
>> Jia He already provided patches for this problem a couple of years ago,
>> but apparently they felt through the cracks and never got merged. So
>> here's a rebased version to finally fix this issue.
>>
>> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1764075
>>
>> Jia He (2):
>> sysctl: introduce new proc handler proc_dobool
>> lockd: change the proc_handler for nsm_use_hostnames
>>
>> fs/lockd/svc.c | 2 +-
>> include/linux/sysctl.h | 2 ++
>> kernel/sysctl.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 45 insertions(+), 1 deletion(-)
>>
>> --
>> 2.27.0
--
Chuck Lever
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines
2021-08-03 10:59 [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines Thomas Huth
` (2 preceding siblings ...)
2021-08-03 14:08 ` [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines J. Bruce Fields
@ 2021-08-04 2:12 ` Jia He
2021-08-09 17:50 ` Chuck Lever III
4 siblings, 0 replies; 9+ messages in thread
From: Jia He @ 2021-08-04 2:12 UTC (permalink / raw)
To: Thomas Huth, linux-kernel, linux-fsdevel, linux-nfs
Cc: J. Bruce Fields, Chuck Lever, Trond Myklebust, Anna Schumaker,
Luis Chamberlain, Kees Cook, Iurii Zaikin, linux-s390,
Pan Xinhui
On 2021/8/3 18:59, Thomas Huth wrote:
> There is an endianess problem with /proc/sys/fs/nfs/nsm_use_hostnames
> (which can e.g. be seen on an s390x host) :
>
> # modprobe lockd nsm_use_hostnames=1
> # cat /proc/sys/fs/nfs/nsm_use_hostnames
> 16777216
>
> The nsm_use_hostnames variable is declared as "bool" which is required
> for the correct type for the module parameter. However, this does not
> work correctly with the entry in the /proc filesystem since this
> currently requires "int".
>
> Jia He already provided patches for this problem a couple of years ago,
> but apparently they felt through the cracks and never got merged. So
> here's a rebased version to finally fix this issue.
>
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1764075
>
> Jia He (2):
> sysctl: introduce new proc handler proc_dobool
> lockd: change the proc_handler for nsm_use_hostnames
Thanks for picking them up ;-)
---
Cheers,
Justin (Jia He)
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines
2021-08-03 10:59 [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines Thomas Huth
` (3 preceding siblings ...)
2021-08-04 2:12 ` Jia He
@ 2021-08-09 17:50 ` Chuck Lever III
4 siblings, 0 replies; 9+ messages in thread
From: Chuck Lever III @ 2021-08-09 17:50 UTC (permalink / raw)
To: Thomas Huth
Cc: LKML, linux-fsdevel, Linux NFS Mailing List, Bruce Fields,
Trond Myklebust, Anna Schumaker, Luis Chamberlain, Kees Cook,
Iurii Zaikin, linux-s390, Jia He, Pan Xinhui
> On Aug 3, 2021, at 6:59 AM, Thomas Huth <thuth@redhat.com> wrote:
>
> There is an endianess problem with /proc/sys/fs/nfs/nsm_use_hostnames
> (which can e.g. be seen on an s390x host) :
>
> # modprobe lockd nsm_use_hostnames=1
> # cat /proc/sys/fs/nfs/nsm_use_hostnames
> 16777216
>
> The nsm_use_hostnames variable is declared as "bool" which is required
> for the correct type for the module parameter. However, this does not
> work correctly with the entry in the /proc filesystem since this
> currently requires "int".
>
> Jia He already provided patches for this problem a couple of years ago,
> but apparently they felt through the cracks and never got merged. So
> here's a rebased version to finally fix this issue.
>
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1764075
>
> Jia He (2):
> sysctl: introduce new proc handler proc_dobool
> lockd: change the proc_handler for nsm_use_hostnames
>
> fs/lockd/svc.c | 2 +-
> include/linux/sysctl.h | 2 ++
> kernel/sysctl.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 45 insertions(+), 1 deletion(-)
>
> --
> 2.27.0
To get these patches in front of our zero-day apparatus,
I've applied them to the for-next topic branch here:
https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/log/?h=for-next
However I haven't seen an Ack for the kernel/sysctl.c change yet.
--
Chuck Lever
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] sysctl: introduce new proc handler proc_dobool
2021-08-03 10:59 ` [PATCH 1/2] sysctl: introduce new proc handler proc_dobool Thomas Huth
@ 2021-09-16 22:03 ` Kees Cook
0 siblings, 0 replies; 9+ messages in thread
From: Kees Cook @ 2021-09-16 22:03 UTC (permalink / raw)
To: Thomas Huth
Cc: linux-kernel, linux-fsdevel, linux-nfs, J. Bruce Fields,
Chuck Lever, Trond Myklebust, Anna Schumaker, Luis Chamberlain,
Iurii Zaikin, linux-s390, Jia He, Pan Xinhui
On Tue, Aug 03, 2021 at 12:59:36PM +0200, Thomas Huth wrote:
> From: Jia He <hejianet@gmail.com>
>
> This is to let bool variable could be correctly displayed in
> big/little endian sysctl procfs. sizeof(bool) is arch dependent,
> proc_dobool should work in all arches.
>
> Suggested-by: Pan Xinhui <xinhui@linux.vnet.ibm.com>
> Signed-off-by: Jia He <hejianet@gmail.com>
Hi! I apologize for the delay. Yes, this looks good to me; thanks!
Acked-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 2/2] lockd: change the proc_handler for nsm_use_hostnames
2021-08-03 10:59 ` [PATCH 2/2] lockd: change the proc_handler for nsm_use_hostnames Thomas Huth
@ 2021-09-16 22:05 ` Kees Cook
0 siblings, 0 replies; 9+ messages in thread
From: Kees Cook @ 2021-09-16 22:05 UTC (permalink / raw)
To: Thomas Huth
Cc: linux-kernel, linux-fsdevel, linux-nfs, J. Bruce Fields,
Chuck Lever, Trond Myklebust, Anna Schumaker, Luis Chamberlain,
Iurii Zaikin, linux-s390, Jia He, Pan Xinhui
On Tue, Aug 03, 2021 at 12:59:37PM +0200, Thomas Huth wrote:
> From: Jia He <hejianet@gmail.com>
>
> nsm_use_hostnames is a module parameter and it will be exported to sysctl
> procfs. This is to let user sometimes change it from userspace. But the
> minimal unit for sysctl procfs read/write it sizeof(int).
> In big endian system, the converting from/to bool to/from int will cause
> error for proc items.
>
> This patch use a new proc_handler proc_dobool to fix it.
>
> Signed-off-by: Jia He <hejianet@gmail.com>
> Reviewed-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
> [thuth: Fix typo in commit message]
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
> fs/lockd/svc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index 2de048f80eb8..0ab9756ed235 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -584,7 +584,7 @@ static struct ctl_table nlm_sysctls[] = {
> .data = &nsm_use_hostnames,
> .maxlen = sizeof(int),
For robustness, maybe this should be:
.maxlen = sizeof(nsm_use_hostnames),
> .mode = 0644,
> - .proc_handler = proc_dointvec,
> + .proc_handler = proc_dobool,
> },
> {
> .procname = "nsm_local_state",
> --
> 2.27.0
>
Reviewed-by: Kees Cook <keescook@chromium.org>
Also, I wonder what other BE-corrupted bools are out there?
--
Kees Cook
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-09-16 22:05 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-03 10:59 ` [PATCH 1/2] sysctl: introduce new proc handler proc_dobool Thomas Huth
2021-09-16 22:03 ` Kees Cook
2021-08-03 10:59 ` [PATCH 2/2] lockd: change the proc_handler for nsm_use_hostnames Thomas Huth
2021-09-16 22:05 ` Kees Cook
2021-08-03 14:08 ` [PATCH 0/2] Fix /proc/sys/fs/nfs/nsm_use_hostnames on big endian machines J. Bruce Fields
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