path: root/src/ipc
diff options
authorRich Felker <>2013-06-28 23:57:58 -0400
committerRich Felker <>2013-06-28 23:57:58 -0400
commit062f40ef3e56021f4a9902095867e35cce6d99c4 (patch)
tree102a798592f8fdc5c74acdec9d8cb673b822cb93 /src/ipc
parent553d566c3f7080cf1f339eebf715db7e5d0b0d76 (diff)
work around wrong kernel type for sem_nsems member of struct semid_ds
rejecting invalid values for n is fine even in the case where a new sem will not be created, since the kernel does its range checks on n even in this case as well. by default, the kernel will bound the limit well below USHRT_MAX anyway, but it's presumably possible that an administrator could override this limit and break things.
Diffstat (limited to 'src/ipc')
1 files changed, 7 insertions, 0 deletions
diff --git a/src/ipc/semget.c b/src/ipc/semget.c
index 5f110e3b..c4a559db 100644
--- a/src/ipc/semget.c
+++ b/src/ipc/semget.c
@@ -1,9 +1,16 @@
#include <sys/sem.h>
+#include <limits.h>
+#include <errno.h>
#include "syscall.h"
#include "ipc.h"
int semget(key_t key, int n, int fl)
+ /* The kernel uses the wrong type for the sem_nsems member
+ * of struct semid_ds, and thus might not check that the
+ * n fits in the correct (per POSIX) userspace type, so
+ * we have to check here. */
+ if (n > USHRT_MAX) return __syscall_ret(-EINVAL);
#ifdef SYS_semget
return syscall(SYS_semget, key, n, fl);