Messages in this thread | | | Date | Fri, 17 Aug 2018 09:53:34 -0700 | From | Davidlohr Bueso <> | Subject | Re: [PATCH v8 2/5] ipc: IPCMNI limit check for semmni |
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On Mon, 18 Jun 2018, Waiman Long wrote:
>For SysV semaphores, the semmni value is the last part of the 4-element >sem number array. To make semmni behave in a similar way to msgmni and >shmmni, we can't directly use the _minmax handler. Instead, a special >sem specific handler is added to check the last argument to make sure >that it is limited to the [0, IPCMNI] range. An error will be returned >if this is not the case. > >Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
>--- > ipc/ipc_sysctl.c | 23 ++++++++++++++++++++++- > ipc/util.h | 9 +++++++++ > 2 files changed, 31 insertions(+), 1 deletion(-) > >diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c >index f87cb29..49f9bf4 100644 >--- a/ipc/ipc_sysctl.c >+++ b/ipc/ipc_sysctl.c >@@ -88,12 +88,33 @@ 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, semmni; >+ struct ipc_namespace *ns = current->nsproxy->ipc_ns; >+ >+ semmni = ns->sem_ctls[3]; >+ ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos); >+ >+ if (!ret) >+ ret = sem_check_semmni(current->nsproxy->ipc_ns); >+ >+ /* >+ * Reset the semmni value if an error happens. >+ */ >+ if (ret) >+ ns->sem_ctls[3] = semmni; >+ 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; >@@ -175,7 +196,7 @@ 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, > }, > #ifdef CONFIG_CHECKPOINT_RESTORE > { >diff --git a/ipc/util.h b/ipc/util.h >index 0aba323..8e9c52c 100644 >--- a/ipc/util.h >+++ b/ipc/util.h >@@ -218,6 +218,15 @@ 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 *)); > >+static inline int sem_check_semmni(struct ipc_namespace *ns) { >+ /* >+ * Check semmni range [0, IPCMNI] >+ * semmni is the last element of sem_ctls[4] array >+ */ >+ return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > IPCMNI)) >+ ? -ERANGE : 0; >+} >+ > #ifdef CONFIG_COMPAT > #include <linux/compat.h> > struct compat_ipc_perm { >-- >1.8.3.1 >
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