[PATCH for-next V2 2/5] IB/core: Add ib_is_udata_cleared

Matan Barak
2015-12-15T18:30:10Z

Extending core and vendor verb commands require us to check that the
unknown part of the user's given command is all zeros.
Adding ib_is_udata_cleared in order to do so.

Signed-off-by: Matan Barak <matanb-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
---
include/rdma/ib_verbs.h | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 9a68a19..33ab4eb 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -50,6 +50,8 @@
#include <linux/workqueue.h>
#include <linux/socket.h>
#include <uapi/linux/if_ether.h>
+#include <linux/string.h>
+#include <linux/slab.h>

#include <linux/atomic.h>
#include <linux/mmu_notifier.h>
@@ -1887,6 +1889,31 @@ static inline int ib_copy_to_udata(struct ib_udata *udata, void *src, size_t len
return copy_to_user(udata->outbuf, src, len) ? -EFAULT : 0;
}

+static inline bool ib_is_udata_cleared(struct ib_udata *udata,
+ size_t offset,
+ size_t len)
+{
+ const void __user *p = udata->inbuf + offset;
+ bool ret = false;
+ u8 *buf;
+
+ if (len > USHRT_MAX)
+ return false;
+
+ buf = kmalloc(len, GFP_KERNEL);
+ if (!buf)
+ return false;
+
+ if (copy_from_user(buf, p, len))
+ goto free;
+
+ ret = !memchr_inv(buf, 0, len);
+
+free:
+ kfree(buf);
+ return ret;
+}
+
/**
* ib_modify_qp_is_ok - Check that the supplied attribute mask
* contains all required attributes and no attributes not allowed for
--
2.1.0