| Message ID | 1520885744-1546-3-git-send-email-longman@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Mar 12, 2018 at 04:15:40PM -0400, Waiman Long wrote: > Checking code is added to check for invalid flags in the ctl_table > and return error if an unknown flag is used. This should be merged with the first patch otherwise there are atomic points in time on the commit log history where invalid values are allowed and that makes no sense. This can probably be expanded to verify semantics further. Details below. > > Signed-off-by: Waiman Long <longman@redhat.com> > --- > fs/proc/proc_sysctl.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c > index 493c975..67c0c82 100644 > --- a/fs/proc/proc_sysctl.c > +++ b/fs/proc/proc_sysctl.c > @@ -1092,6 +1092,16 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table) > return err; > } > > +static int sysctl_check_flags(const char *path, struct ctl_table *table) > +{ > + int err = 0; > + > + if (table->flags & ~CTL_TABLE_FLAGS_ALL) > + err = sysctl_err(path, table, "invalid flags"); What if a range for the upper limit is set but not the lower limit and the user goes over the lower limit? How about the inverse? Do we need both ranges set? Luis
On Mon, 12 Mar 2018 16:15:40 -0400 Waiman Long <longman@redhat.com> wrote: > Checking code is added to check for invalid flags in the ctl_table > and return error if an unknown flag is used. Why? What's wrong with the old code, what value does this change add, etc.
On 03/12/2018 04:46 PM, Luis R. Rodriguez wrote: > On Mon, Mar 12, 2018 at 04:15:40PM -0400, Waiman Long wrote: >> Checking code is added to check for invalid flags in the ctl_table >> and return error if an unknown flag is used. > This should be merged with the first patch otherwise there are atomic > points in time on the commit log history where invalid values are allowed > and that makes no sense. > > This can probably be expanded to verify semantics further. Details > below. >> Signed-off-by: Waiman Long <longman@redhat.com> >> --- >> fs/proc/proc_sysctl.c | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) >> >> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c >> index 493c975..67c0c82 100644 >> --- a/fs/proc/proc_sysctl.c >> +++ b/fs/proc/proc_sysctl.c >> @@ -1092,6 +1092,16 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table) >> return err; >> } >> >> +static int sysctl_check_flags(const char *path, struct ctl_table *table) >> +{ >> + int err = 0; >> + >> + if (table->flags & ~CTL_TABLE_FLAGS_ALL) >> + err = sysctl_err(path, table, "invalid flags"); > What if a range for the upper limit is set but not the lower limit and > the user goes over the lower limit? > > How about the inverse? > > Do we need both ranges set? > > Luis This check is just to make sure that no invalid flag bit is set. Range clamping is just one of flag bits, though this is the only one currently supported. In fact, it is allowed that the minimum or maximum can be left unspecified. In this case, no minimum or maximum checking will be done. So I don't see anything related to range checking should be put here. Cheers, Longman
On Mon, Mar 12, 2018 at 04:54:51PM -0400, Waiman Long wrote: > On 03/12/2018 04:46 PM, Luis R. Rodriguez wrote: > > On Mon, Mar 12, 2018 at 04:15:40PM -0400, Waiman Long wrote: > >> Checking code is added to check for invalid flags in the ctl_table > >> and return error if an unknown flag is used. > > This should be merged with the first patch otherwise there are atomic > > points in time on the commit log history where invalid values are allowed > > and that makes no sense. > > > > This can probably be expanded to verify semantics further. Details > > below. > >> Signed-off-by: Waiman Long <longman@redhat.com> > >> --- > >> fs/proc/proc_sysctl.c | 12 ++++++++++++ > >> 1 file changed, 12 insertions(+) > >> > >> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c > >> index 493c975..67c0c82 100644 > >> --- a/fs/proc/proc_sysctl.c > >> +++ b/fs/proc/proc_sysctl.c > >> @@ -1092,6 +1092,16 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table) > >> return err; > >> } > >> > >> +static int sysctl_check_flags(const char *path, struct ctl_table *table) > >> +{ > >> + int err = 0; > >> + > >> + if (table->flags & ~CTL_TABLE_FLAGS_ALL) > >> + err = sysctl_err(path, table, "invalid flags"); > > What if a range for the upper limit is set but not the lower limit and > > the user goes over the lower limit? > > > > How about the inverse? > > > > Do we need both ranges set? > > > > Luis > > This check is just to make sure that no invalid flag bit is set. Range > clamping is just one of flag bits, though this is the only one currently > supported. In fact, it is allowed that the minimum or maximum can be > left unspecified. In this case, no minimum or maximum checking will be > done. So I don't see anything related to range checking should be put here. What if minimum is greater than maximum? Luis
On 03/12/2018 04:59 PM, Luis R. Rodriguez wrote: > On Mon, Mar 12, 2018 at 04:54:51PM -0400, Waiman Long wrote: >> On 03/12/2018 04:46 PM, Luis R. Rodriguez wrote: >>> On Mon, Mar 12, 2018 at 04:15:40PM -0400, Waiman Long wrote: >>>> Checking code is added to check for invalid flags in the ctl_table >>>> and return error if an unknown flag is used. >>> This should be merged with the first patch otherwise there are atomic >>> points in time on the commit log history where invalid values are allowed >>> and that makes no sense. >>> >>> This can probably be expanded to verify semantics further. Details >>> below. >>>> Signed-off-by: Waiman Long <longman@redhat.com> >>>> --- >>>> fs/proc/proc_sysctl.c | 12 ++++++++++++ >>>> 1 file changed, 12 insertions(+) >>>> >>>> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c >>>> index 493c975..67c0c82 100644 >>>> --- a/fs/proc/proc_sysctl.c >>>> +++ b/fs/proc/proc_sysctl.c >>>> @@ -1092,6 +1092,16 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table) >>>> return err; >>>> } >>>> >>>> +static int sysctl_check_flags(const char *path, struct ctl_table *table) >>>> +{ >>>> + int err = 0; >>>> + >>>> + if (table->flags & ~CTL_TABLE_FLAGS_ALL) >>>> + err = sysctl_err(path, table, "invalid flags"); >>> What if a range for the upper limit is set but not the lower limit and >>> the user goes over the lower limit? >>> >>> How about the inverse? >>> >>> Do we need both ranges set? >>> >>> Luis >> This check is just to make sure that no invalid flag bit is set. Range >> clamping is just one of flag bits, though this is the only one currently >> supported. In fact, it is allowed that the minimum or maximum can be >> left unspecified. In this case, no minimum or maximum checking will be >> done. So I don't see anything related to range checking should be put here. > What if minimum is greater than maximum? > > Luis Yes, you are right. That is a valid check. I am going to add that in the next patch. Cheers, Longman
On 03/12/2018 04:52 PM, Andrew Morton wrote: > On Mon, 12 Mar 2018 16:15:40 -0400 Waiman Long <longman@redhat.com> wrote: > >> Checking code is added to check for invalid flags in the ctl_table >> and return error if an unknown flag is used. > Why? What's wrong with the old code, what value does this change add, > etc. This is an additional checking code requested by Luis. Cheers, Longman
On Mon, 12 Mar 2018 18:12:47 -0400 Waiman Long <longman@redhat.com> wrote: > On 03/12/2018 04:52 PM, Andrew Morton wrote: > > On Mon, 12 Mar 2018 16:15:40 -0400 Waiman Long <longman@redhat.com> wrote: > > > >> Checking code is added to check for invalid flags in the ctl_table > >> and return error if an unknown flag is used. > > Why? What's wrong with the old code, what value does this change add, > > etc. > > This is an additional checking code requested by Luis. Readers of this patch will wish to know why it exists. That doesn't tell us!
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 493c975..67c0c82 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1092,6 +1092,16 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table) return err; } +static int sysctl_check_flags(const char *path, struct ctl_table *table) +{ + int err = 0; + + if (table->flags & ~CTL_TABLE_FLAGS_ALL) + err = sysctl_err(path, table, "invalid flags"); + + return err; +} + static int sysctl_check_table(const char *path, struct ctl_table *table) { int err = 0; @@ -1111,6 +1121,8 @@ static int sysctl_check_table(const char *path, struct ctl_table *table) (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { if (!table->data) err |= sysctl_err(path, table, "No data"); + if (table->flags) + err |= sysctl_check_flags(path, table); if (!table->maxlen) err |= sysctl_err(path, table, "No maxlen"); else
Checking code is added to check for invalid flags in the ctl_table and return error if an unknown flag is used. Signed-off-by: Waiman Long <longman@redhat.com> --- fs/proc/proc_sysctl.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)