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authorWaiman Long <longman@redhat.com>2018-10-30 15:07:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-31 08:54:14 -0700
commit8c81ddd2acd2c10979f5a64f6784ce7c6717495e (patch)
tree753eefd7695e89bd0667bb877123be642c134642 /ipc
parent6730e6580177d13f4612767873cb5a533ad63c61 (diff)
downloadlinux-stericsson-8c81ddd2acd2c10979f5a64f6784ce7c6717495e.tar.gz
ipc: IPCMNI limit check for semmni
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. Link: http://lkml.kernel.org/r/1536352137-12003-3-git-send-email-longman@redhat.com Signed-off-by: Waiman Long <longman@redhat.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/ipc_sysctl.c23
-rw-r--r--ipc/util.h9
2 files changed, 31 insertions, 1 deletions
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index f87cb29436ef..49f9bf4ffc7f 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 struct ctl_table ipc_kern_table[] = {
.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 1ee81bce25e9..d768fdbed515 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -217,6 +217,15 @@ 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 {