Last batch of InfiniBand/RDMA changes for 3.13 / 2014:

- Additional checks for uverbs to ensure forward compatibility, handle
    malformed input better.
  - Fix potential use-after-free in iWARP connection manager.
  - Make a function static.
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Merge tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband

Pull infiniband fixes from Roland Dreier:
 "Last batch of InfiniBand/RDMA changes for 3.13 / 2014:
   - Additional checks for uverbs to ensure forward compatibility,
     handle malformed input better.
   - Fix potential use-after-free in iWARP connection manager.
   - Make a function static"

* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
  IB/uverbs: Check access to userspace response buffer in extended command
  IB/uverbs: Check input length in flow steering uverbs
  IB/uverbs: Set error code when fail to consume all flow_spec items
  IB/uverbs: Check reserved fields in create_flow
  IB/uverbs: Check comp_mask in destroy_flow
  IB/uverbs: Check reserved field in extended command header
  IB/uverbs: New macro to set pointers to NULL if length is 0 in INIT_UDATA()
  IB/core: const'ify inbuf in struct ib_udata
  RDMA/iwcm: Don't touch cm_id after deref in rem_ref
  RDMA/cxgb4: Make _c4iw_write_mem_dma() static

drivers/infiniband/core/iwcm.c

@@ -181,9 +181,16 @@ static void add_ref(struct iw_cm_id *cm_id)
 static void rem_ref(struct iw_cm_id *cm_id)
 {
 	struct iwcm_id_private *cm_id_priv;
+	int cb_destroy;
+
 	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
-	if (iwcm_deref_id(cm_id_priv) &&
-	    test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags)) {
+
+	/*
+	 * Test bit before deref in case the cm_id gets freed on another
+	 * thread.
+	 */
+	cb_destroy = test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
+	if (iwcm_deref_id(cm_id_priv) && cb_destroy) {
 		BUG_ON(!list_empty(&cm_id_priv->work_list));
 		free_cm_id(cm_id_priv);
 	}

drivers/infiniband/core/uverbs.h

@@ -49,12 +49,20 @@
 
 #define INIT_UDATA(udata, ibuf, obuf, ilen, olen)			\
 	do {								\
-		(udata)->inbuf  = (void __user *) (ibuf);		\
+		(udata)->inbuf  = (const void __user *) (ibuf);		\
 		(udata)->outbuf = (void __user *) (obuf);		\
 		(udata)->inlen  = (ilen);				\
 		(udata)->outlen = (olen);				\
 	} while (0)
 
+#define INIT_UDATA_BUF_OR_NULL(udata, ibuf, obuf, ilen, olen)			\
+	do {									\
+		(udata)->inbuf  = (ilen) ? (const void __user *) (ibuf) : NULL;	\
+		(udata)->outbuf = (olen) ? (void __user *) (obuf) : NULL;	\
+		(udata)->inlen  = (ilen);					\
+		(udata)->outlen = (olen);					\
+	} while (0)
+
 /*
  * Our lifetime rules for these structs are the following:
  *

drivers/infiniband/core/uverbs_cmd.c

@@ -2593,6 +2593,9 @@ out_put:
 static int kern_spec_to_ib_spec(struct ib_uverbs_flow_spec *kern_spec,
 				union ib_flow_spec *ib_spec)
 {
+	if (kern_spec->reserved)
+		return -EINVAL;
+
 	ib_spec->type = kern_spec->type;
 
 	switch (ib_spec->type) {
@@ -2646,6 +2649,9 @@ int ib_uverbs_ex_create_flow(struct ib_uverbs_file *file,
 	void *ib_spec;
 	int i;
 
+	if (ucore->inlen < sizeof(cmd))
+		return -EINVAL;
+
 	if (ucore->outlen < sizeof(resp))
 		return -ENOSPC;
 
@@ -2671,6 +2677,10 @@ int ib_uverbs_ex_create_flow(struct ib_uverbs_file *file,
 	    (cmd.flow_attr.num_of_specs * sizeof(struct ib_uverbs_flow_spec)))
 		return -EINVAL;
 
+	if (cmd.flow_attr.reserved[0] ||
+	    cmd.flow_attr.reserved[1])
+		return -EINVAL;
+
 	if (cmd.flow_attr.num_of_specs) {
 		kern_flow_attr = kmalloc(sizeof(*kern_flow_attr) + cmd.flow_attr.size,
 					 GFP_KERNEL);
@@ -2731,6 +2741,7 @@ int ib_uverbs_ex_create_flow(struct ib_uverbs_file *file,
 	if (cmd.flow_attr.size || (i != flow_attr->num_of_specs)) {
 		pr_warn("create flow failed, flow %d: %d bytes left from uverb cmd\n",
 			i, cmd.flow_attr.size);
+		err = -EINVAL;
 		goto err_free;
 	}
 	flow_id = ib_create_flow(qp, flow_attr, IB_FLOW_DOMAIN_USER);
@@ -2791,10 +2802,16 @@ int ib_uverbs_ex_destroy_flow(struct ib_uverbs_file *file,
 	struct ib_uobject		*uobj;
 	int				ret;
 
+	if (ucore->inlen < sizeof(cmd))
+		return -EINVAL;
+
 	ret = ib_copy_from_udata(&cmd, ucore, sizeof(cmd));
 	if (ret)
 		return ret;
 
+	if (cmd.comp_mask)
+		return -EINVAL;
+
 	uobj = idr_write_uobj(&ib_uverbs_rule_idr, cmd.flow_handle,
 			      file->ucontext);
 	if (!uobj)

drivers/infiniband/core/uverbs_main.c

@@ -668,25 +668,30 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
 		if ((hdr.in_words + ex_hdr.provider_in_words) * 8 != count)
 			return -EINVAL;
 
+		if (ex_hdr.cmd_hdr_reserved)
+			return -EINVAL;
+
 		if (ex_hdr.response) {
 			if (!hdr.out_words && !ex_hdr.provider_out_words)
 				return -EINVAL;
+
+			if (!access_ok(VERIFY_WRITE,
+				       (void __user *) (unsigned long) ex_hdr.response,
+				       (hdr.out_words + ex_hdr.provider_out_words) * 8))
+				return -EFAULT;
 		} else {
 			if (hdr.out_words || ex_hdr.provider_out_words)
 				return -EINVAL;
 		}
 
-		INIT_UDATA(&ucore,
-			   (hdr.in_words) ? buf : 0,
-			   (unsigned long)ex_hdr.response,
-			   hdr.in_words * 8,
-			   hdr.out_words * 8);
+		INIT_UDATA_BUF_OR_NULL(&ucore, buf, (unsigned long) ex_hdr.response,
+				       hdr.in_words * 8, hdr.out_words * 8);
 
-		INIT_UDATA(&uhw,
-			   (ex_hdr.provider_in_words) ? buf + ucore.inlen : 0,
-			   (ex_hdr.provider_out_words) ? (unsigned long)ex_hdr.response + ucore.outlen : 0,
-			   ex_hdr.provider_in_words * 8,
-			   ex_hdr.provider_out_words * 8);
+		INIT_UDATA_BUF_OR_NULL(&uhw,
+				       buf + ucore.inlen,
+				       (unsigned long) ex_hdr.response + ucore.outlen,
+				       ex_hdr.provider_in_words * 8,
+				       ex_hdr.provider_out_words * 8);
 
 		err = uverbs_ex_cmd_table[command](file,
 						   &ucore,

drivers/infiniband/hw/cxgb4/mem.c

@@ -173,7 +173,7 @@ static int _c4iw_write_mem_inline(struct c4iw_rdev *rdev, u32 addr, u32 len,
 	return ret;
 }
 
-int _c4iw_write_mem_dma(struct c4iw_rdev *rdev, u32 addr, u32 len, void *data)
+static int _c4iw_write_mem_dma(struct c4iw_rdev *rdev, u32 addr, u32 len, void *data)
 {
 	u32 remain = len;
 	u32 dmalen;

include/rdma/ib_verbs.h

@@ -978,7 +978,7 @@ struct ib_uobject {
 };
 
 struct ib_udata {
-	void __user *inbuf;
+	const void __user *inbuf;
 	void __user *outbuf;
 	size_t       inlen;
 	size_t       outlen;