| Message ID | 1519926220-7453-7-git-send-email-longman@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Mar 01, 2018 at 12:43:40PM -0500, Waiman Long wrote: > This patch clamps the semmni value (fourth element of sem_ctls[] > array) to within the [0, IPCMNI] range and prints a warning message > once when an out-of-range value is being written. > > Signed-off-by: Waiman Long <longman@redhat.com> > --- > ipc/ipc_sysctl.c | 13 ++++++++++++- > ipc/sem.c | 28 ++++++++++++++++++++++++++++ > ipc/util.h | 4 ++++ > 3 files changed, 44 insertions(+), 1 deletion(-) > > diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c > index 8eb7268..2c03f57 100644 > --- a/ipc/ipc_sysctl.c > +++ b/ipc/ipc_sysctl.c > @@ -97,12 +97,22 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, > return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); > } > > +static int proc_ipc_sem_dointvec(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + int ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos); > + > + sem_check_semmni(table, current->nsproxy->ipc_ns); > + return ret; > +} > + > #else > #define proc_ipc_doulongvec_minmax NULL > #define proc_ipc_dointvec NULL > #define proc_ipc_dointvec_minmax NULL > #define proc_ipc_dointvec_minmax_orphans NULL > #define proc_ipc_auto_msgmni NULL > +#define proc_ipc_sem_dointvec NULL > #endif > > static int zero; > @@ -186,7 +196,8 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, > .data = &init_ipc_ns.sem_ctls, > .maxlen = 4*sizeof(int), > .mode = 0644, > - .proc_handler = proc_ipc_dointvec, > + .proc_handler = proc_ipc_sem_dointvec, > + .flags = CTL_FLAGS_CLAMP_RANGE, > }, > #ifdef CONFIG_CHECKPOINT_RESTORE > { > diff --git a/ipc/sem.c b/ipc/sem.c > index a4af049..739dfca 100644 > --- a/ipc/sem.c > +++ b/ipc/sem.c > @@ -2337,3 +2337,31 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it) > return 0; > } > #endif > + > +#ifdef CONFIG_PROC_SYSCTL > +/* > + * Check to see if semmni is out of range and clamp it if necessary. > + */ > +void sem_check_semmni(struct ctl_table *table, struct ipc_namespace *ns) > +{ > + bool clamped = false; > + > + if (!(table->flags & CTL_FLAGS_CLAMP_RANGE)) > + return; > + > + /* > + * Clamp semmni to the range [0, IPCMNI]. > + */ > + if (ns->sc_semmni < 0) { > + ns->sc_semmni = 0; > + clamped = true; > + } > + if (ns->sc_semmni > IPCMNI) { > + ns->sc_semmni = IPCMNI; > + clamped = true; > + } > + if (clamped) > + pr_warn_once("Kernel parameter \"sem[3]\" was set out of range [%d, %d], clamped to %d.\n", > + 0, IPCMNI, ns->sc_semmni); Why are the users issuing a warning, wouldn't the API do the warning on its own, specially since we're adding a warn flag? Luis
On 03/08/2018 01:15 PM, Luis R. Rodriguez wrote: > On Thu, Mar 01, 2018 at 12:43:40PM -0500, Waiman Long wrote: >> This patch clamps the semmni value (fourth element of sem_ctls[] >> array) to within the [0, IPCMNI] range and prints a warning message >> once when an out-of-range value is being written. >> >> Signed-off-by: Waiman Long <longman@redhat.com> >> --- >> ipc/ipc_sysctl.c | 13 ++++++++++++- >> ipc/sem.c | 28 ++++++++++++++++++++++++++++ >> ipc/util.h | 4 ++++ >> 3 files changed, 44 insertions(+), 1 deletion(-) >> >> diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c >> index 8eb7268..2c03f57 100644 >> --- a/ipc/ipc_sysctl.c >> +++ b/ipc/ipc_sysctl.c >> @@ -97,12 +97,22 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, >> return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); >> } >> >> +static int proc_ipc_sem_dointvec(struct ctl_table *table, int write, >> + void __user *buffer, size_t *lenp, loff_t *ppos) >> +{ >> + int ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos); >> + >> + sem_check_semmni(table, current->nsproxy->ipc_ns); >> + return ret; >> +} >> + >> #else >> #define proc_ipc_doulongvec_minmax NULL >> #define proc_ipc_dointvec NULL >> #define proc_ipc_dointvec_minmax NULL >> #define proc_ipc_dointvec_minmax_orphans NULL >> #define proc_ipc_auto_msgmni NULL >> +#define proc_ipc_sem_dointvec NULL >> #endif >> >> static int zero; >> @@ -186,7 +196,8 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, >> .data = &init_ipc_ns.sem_ctls, >> .maxlen = 4*sizeof(int), >> .mode = 0644, >> - .proc_handler = proc_ipc_dointvec, >> + .proc_handler = proc_ipc_sem_dointvec, >> + .flags = CTL_FLAGS_CLAMP_RANGE, >> }, >> #ifdef CONFIG_CHECKPOINT_RESTORE >> { >> diff --git a/ipc/sem.c b/ipc/sem.c >> index a4af049..739dfca 100644 >> --- a/ipc/sem.c >> +++ b/ipc/sem.c >> @@ -2337,3 +2337,31 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it) >> return 0; >> } >> #endif >> + >> +#ifdef CONFIG_PROC_SYSCTL >> +/* >> + * Check to see if semmni is out of range and clamp it if necessary. >> + */ >> +void sem_check_semmni(struct ctl_table *table, struct ipc_namespace *ns) >> +{ >> + bool clamped = false; >> + >> + if (!(table->flags & CTL_FLAGS_CLAMP_RANGE)) >> + return; >> + >> + /* >> + * Clamp semmni to the range [0, IPCMNI]. >> + */ >> + if (ns->sc_semmni < 0) { >> + ns->sc_semmni = 0; >> + clamped = true; >> + } >> + if (ns->sc_semmni > IPCMNI) { >> + ns->sc_semmni = IPCMNI; >> + clamped = true; >> + } >> + if (clamped) >> + pr_warn_once("Kernel parameter \"sem[3]\" was set out of range [%d, %d], clamped to %d.\n", >> + 0, IPCMNI, ns->sc_semmni); > Why are the users issuing a warning, wouldn't the API do the warning > on its own, specially since we're adding a warn flag? > > Luis This is a special case as the semmni parameter is actually embedded in the sem sysctl paramter as the last argument of the 4. So the previous sysctl patches won't have any effect on this one. I did this patch to make all the IPC *mni parameters have the same behavior for consistency purpose. Cheers, Longman
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index 8eb7268..2c03f57 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c @@ -97,12 +97,22 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); } +static int proc_ipc_sem_dointvec(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos); + + sem_check_semmni(table, current->nsproxy->ipc_ns); + return ret; +} + #else #define proc_ipc_doulongvec_minmax NULL #define proc_ipc_dointvec NULL #define proc_ipc_dointvec_minmax NULL #define proc_ipc_dointvec_minmax_orphans NULL #define proc_ipc_auto_msgmni NULL +#define proc_ipc_sem_dointvec NULL #endif static int zero; @@ -186,7 +196,8 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, .data = &init_ipc_ns.sem_ctls, .maxlen = 4*sizeof(int), .mode = 0644, - .proc_handler = proc_ipc_dointvec, + .proc_handler = proc_ipc_sem_dointvec, + .flags = CTL_FLAGS_CLAMP_RANGE, }, #ifdef CONFIG_CHECKPOINT_RESTORE { diff --git a/ipc/sem.c b/ipc/sem.c index a4af049..739dfca 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -2337,3 +2337,31 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it) return 0; } #endif + +#ifdef CONFIG_PROC_SYSCTL +/* + * Check to see if semmni is out of range and clamp it if necessary. + */ +void sem_check_semmni(struct ctl_table *table, struct ipc_namespace *ns) +{ + bool clamped = false; + + if (!(table->flags & CTL_FLAGS_CLAMP_RANGE)) + return; + + /* + * Clamp semmni to the range [0, IPCMNI]. + */ + if (ns->sc_semmni < 0) { + ns->sc_semmni = 0; + clamped = true; + } + if (ns->sc_semmni > IPCMNI) { + ns->sc_semmni = IPCMNI; + clamped = true; + } + if (clamped) + pr_warn_once("Kernel parameter \"sem[3]\" was set out of range [%d, %d], clamped to %d.\n", + 0, IPCMNI, ns->sc_semmni); +} +#endif diff --git a/ipc/util.h b/ipc/util.h index 89b8ec1..af57394 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -206,6 +206,10 @@ int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); +#ifdef CONFIG_PROC_SYSCTL +extern void sem_check_semmni(struct ctl_table *table, struct ipc_namespace *ns); +#endif + #ifdef CONFIG_COMPAT #include <linux/compat.h> struct compat_ipc_perm {
This patch clamps the semmni value (fourth element of sem_ctls[] array) to within the [0, IPCMNI] range and prints a warning message once when an out-of-range value is being written. Signed-off-by: Waiman Long <longman@redhat.com> --- ipc/ipc_sysctl.c | 13 ++++++++++++- ipc/sem.c | 28 ++++++++++++++++++++++++++++ ipc/util.h | 4 ++++ 3 files changed, 44 insertions(+), 1 deletion(-)