Merge branch 'rds-fixes'

Shamir Rabinovitch says:

====================
WARNING in rds_message_alloc_sgs

This patch set fix google syzbot rds bug found in linux-next.
The first patch solve the syzbot issue.
The second patch fix issue mentioned by Leon Romanovsky that
drivers should not call WARN_ON as result from user input.

syzbot bug report can be foud here: https://lkml.org/lkml/2018/10/31/28

v1->v2:
- patch 1: make rds_iov_vector fields name more descriptive (Hakon)
- patch 1: fix potential mem leak in rds_rm_size if krealloc fail
  (Hakon)
v2->v3:
- patch 2: harden rds_sendmsg for invalid number of sgs (Gerd)
v3->v4
- Santosh a.b. on both patches + repost to net-dev
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/message.c

@@ -308,16 +308,27 @@ struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)
 /*
  * RDS ops use this to grab SG entries from the rm's sg pool.
  */
-struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
+struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents,
+					  int *ret)
 {
 	struct scatterlist *sg_first = (struct scatterlist *) &rm[1];
 	struct scatterlist *sg_ret;
 
-	WARN_ON(rm->m_used_sgs + nents > rm->m_total_sgs);
-	WARN_ON(!nents);
+	if (WARN_ON(!ret))
+		return NULL;
 
-	if (rm->m_used_sgs + nents > rm->m_total_sgs)
+	if (nents <= 0) {
+		pr_warn("rds: alloc sgs failed! nents <= 0\n");
+		*ret = -EINVAL;
 		return NULL;
+	}
+
+	if (rm->m_used_sgs + nents > rm->m_total_sgs) {
+		pr_warn("rds: alloc sgs failed! total %d used %d nents %d\n",
+			rm->m_total_sgs, rm->m_used_sgs, nents);
+		*ret = -ENOMEM;
+		return NULL;
+	}
 
 	sg_ret = &sg_first[rm->m_used_sgs];
 	sg_init_table(sg_ret, nents);
@@ -332,6 +343,7 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in
 	unsigned int i;
 	int num_sgs = ceil(total_len, PAGE_SIZE);
 	int extra_bytes = num_sgs * sizeof(struct scatterlist);
+	int ret;
 
 	rm = rds_message_alloc(extra_bytes, GFP_NOWAIT);
 	if (!rm)
@@ -340,10 +352,10 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in
 	set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
 	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
 	rm->data.op_nents = ceil(total_len, PAGE_SIZE);
-	rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
+	rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs, &ret);
 	if (!rm->data.op_sg) {
 		rds_message_put(rm);
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR(ret);
 	}
 
 	for (i = 0; i < rm->data.op_nents; ++i) {

net/rds/rdma.c

@@ -517,9 +517,10 @@ static int rds_rdma_pages(struct rds_iovec iov[], int nr_iovecs)
 	return tot_pages;
 }
 
-int rds_rdma_extra_size(struct rds_rdma_args *args)
+int rds_rdma_extra_size(struct rds_rdma_args *args,
+			struct rds_iov_vector *iov)
 {
-	struct rds_iovec vec;
+	struct rds_iovec *vec;
 	struct rds_iovec __user *local_vec;
 	int tot_pages = 0;
 	unsigned int nr_pages;
@@ -530,13 +531,23 @@ int rds_rdma_extra_size(struct rds_rdma_args *args)
 	if (args->nr_local == 0)
 		return -EINVAL;
 
+	iov->iov = kcalloc(args->nr_local,
+			   sizeof(struct rds_iovec),
+			   GFP_KERNEL);
+	if (!iov->iov)
+		return -ENOMEM;
+
+	vec = &iov->iov[0];
+
+	if (copy_from_user(vec, local_vec, args->nr_local *
+			   sizeof(struct rds_iovec)))
+		return -EFAULT;
+	iov->len = args->nr_local;
+
 	/* figure out the number of pages in the vector */
-	for (i = 0; i < args->nr_local; i++) {
-		if (copy_from_user(&vec, &local_vec[i],
-				   sizeof(struct rds_iovec)))
-			return -EFAULT;
+	for (i = 0; i < args->nr_local; i++, vec++) {
 
-		nr_pages = rds_pages_in_vec(&vec);
+		nr_pages = rds_pages_in_vec(vec);
 		if (nr_pages == 0)
 			return -EINVAL;
 
@@ -558,15 +569,15 @@ int rds_rdma_extra_size(struct rds_rdma_args *args)
  * Extract all arguments and set up the rdma_op
  */
 int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
-			  struct cmsghdr *cmsg)
+		       struct cmsghdr *cmsg,
+		       struct rds_iov_vector *vec)
 {
 	struct rds_rdma_args *args;
 	struct rm_rdma_op *op = &rm->rdma;
 	int nr_pages;
 	unsigned int nr_bytes;
 	struct page **pages = NULL;
-	struct rds_iovec iovstack[UIO_FASTIOV], *iovs = iovstack;
-	int iov_size;
+	struct rds_iovec *iovs;
 	unsigned int i, j;
 	int ret = 0;
 
@@ -586,31 +597,23 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
 		goto out_ret;
 	}
 
-	/* Check whether to allocate the iovec area */
-	iov_size = args->nr_local * sizeof(struct rds_iovec);
-	if (args->nr_local > UIO_FASTIOV) {
-		iovs = sock_kmalloc(rds_rs_to_sk(rs), iov_size, GFP_KERNEL);
-		if (!iovs) {
-			ret = -ENOMEM;
-			goto out_ret;
-		}
+	if (vec->len != args->nr_local) {
+		ret = -EINVAL;
+		goto out_ret;
 	}
 
-	if (copy_from_user(iovs, (struct rds_iovec __user *)(unsigned long) args->local_vec_addr, iov_size)) {
-		ret = -EFAULT;
-		goto out;
-	}
+	iovs = vec->iov;
 
 	nr_pages = rds_rdma_pages(iovs, args->nr_local);
 	if (nr_pages < 0) {
 		ret = -EINVAL;
-		goto out;
+		goto out_ret;
 	}
 
 	pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 	if (!pages) {
 		ret = -ENOMEM;
-		goto out;
+		goto out_ret;
 	}
 
 	op->op_write = !!(args->flags & RDS_RDMA_READWRITE);
@@ -620,11 +623,9 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
 	op->op_active = 1;
 	op->op_recverr = rs->rs_recverr;
 	WARN_ON(!nr_pages);
-	op->op_sg = rds_message_alloc_sgs(rm, nr_pages);
-	if (!op->op_sg) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	op->op_sg = rds_message_alloc_sgs(rm, nr_pages, &ret);
+	if (!op->op_sg)
+		goto out_pages;
 
 	if (op->op_notify || op->op_recverr) {
 		/* We allocate an uninitialized notifier here, because
@@ -635,7 +636,7 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
 		op->op_notifier = kmalloc(sizeof(struct rds_notifier), GFP_KERNEL);
 		if (!op->op_notifier) {
 			ret = -ENOMEM;
-			goto out;
+			goto out_pages;
 		}
 		op->op_notifier->n_user_token = args->user_token;
 		op->op_notifier->n_status = RDS_RDMA_SUCCESS;
@@ -681,7 +682,7 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
 		 */
 		ret = rds_pin_pages(iov->addr, nr, pages, !op->op_write);
 		if (ret < 0)
-			goto out;
+			goto out_pages;
 		else
 			ret = 0;
 
@@ -714,13 +715,11 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
 				nr_bytes,
 				(unsigned int) args->remote_vec.bytes);
 		ret = -EINVAL;
-		goto out;
+		goto out_pages;
 	}
 	op->op_bytes = nr_bytes;
 
-out:
-	if (iovs != iovstack)
-		sock_kfree_s(rds_rs_to_sk(rs), iovs, iov_size);
+out_pages:
 	kfree(pages);
 out_ret:
 	if (ret)
@@ -838,11 +837,9 @@ int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
 	rm->atomic.op_silent = !!(args->flags & RDS_RDMA_SILENT);
 	rm->atomic.op_active = 1;
 	rm->atomic.op_recverr = rs->rs_recverr;
-	rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1);
-	if (!rm->atomic.op_sg) {
-		ret = -ENOMEM;
+	rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1, &ret);
+	if (!rm->atomic.op_sg)
 		goto err;
-	}
 
 	/* verify 8 byte-aligned */
 	if (args->local_addr & 0x7) {

net/rds/rds.h

@@ -386,6 +386,18 @@ static inline void rds_message_zcopy_queue_init(struct rds_msg_zcopy_queue *q)
 	INIT_LIST_HEAD(&q->zcookie_head);
 }
 
+struct rds_iov_vector {
+	struct rds_iovec *iov;
+	int               len;
+};
+
+struct rds_iov_vector_arr {
+	struct rds_iov_vector *vec;
+	int                    len;
+	int                    indx;
+	int                    incr;
+};
+
 struct rds_message {
 	refcount_t		m_refcount;
 	struct list_head	m_sock_item;
@@ -827,7 +839,8 @@ rds_conn_connecting(struct rds_connection *conn)
 
 /* message.c */
 struct rds_message *rds_message_alloc(unsigned int nents, gfp_t gfp);
-struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents);
+struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents,
+					  int *ret);
 int rds_message_copy_from_user(struct rds_message *rm, struct iov_iter *from,
 			       bool zcopy);
 struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len);
@@ -904,13 +917,13 @@ int rds_get_mr(struct rds_sock *rs, char __user *optval, int optlen);
 int rds_get_mr_for_dest(struct rds_sock *rs, char __user *optval, int optlen);
 int rds_free_mr(struct rds_sock *rs, char __user *optval, int optlen);
 void rds_rdma_drop_keys(struct rds_sock *rs);
-int rds_rdma_extra_size(struct rds_rdma_args *args);
-int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
-			  struct cmsghdr *cmsg);
+int rds_rdma_extra_size(struct rds_rdma_args *args,
+			struct rds_iov_vector *iov);
 int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,
 			  struct cmsghdr *cmsg);
 int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
-			  struct cmsghdr *cmsg);
+			  struct cmsghdr *cmsg,
+			  struct rds_iov_vector *vec);
 int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,
 			  struct cmsghdr *cmsg);
 void rds_rdma_free_op(struct rm_rdma_op *ro);

net/rds/send.c

@@ -876,13 +876,18 @@ static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
  * rds_message is getting to be quite complicated, and we'd like to allocate
  * it all in one go. This figures out how big it needs to be up front.
  */
-static int rds_rm_size(struct msghdr *msg, int num_sgs)
+static int rds_rm_size(struct msghdr *msg, int num_sgs,
+		       struct rds_iov_vector_arr *vct)
 {
 	struct cmsghdr *cmsg;
 	int size = 0;
 	int cmsg_groups = 0;
 	int retval;
 	bool zcopy_cookie = false;
+	struct rds_iov_vector *iov, *tmp_iov;
+
+	if (num_sgs < 0)
+		return -EINVAL;
 
 	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
@@ -893,8 +898,24 @@ static int rds_rm_size(struct msghdr *msg, int num_sgs)
 
 		switch (cmsg->cmsg_type) {
 		case RDS_CMSG_RDMA_ARGS:
+			if (vct->indx >= vct->len) {
+				vct->len += vct->incr;
+				tmp_iov =
+					krealloc(vct->vec,
+						 vct->len *
+						 sizeof(struct rds_iov_vector),
+						 GFP_KERNEL);
+				if (!tmp_iov) {
+					vct->len -= vct->incr;
+					return -ENOMEM;
+				}
+				vct->vec = tmp_iov;
+			}
+			iov = &vct->vec[vct->indx];
+			memset(iov, 0, sizeof(struct rds_iov_vector));
+			vct->indx++;
 			cmsg_groups |= 1;
-			retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
+			retval = rds_rdma_extra_size(CMSG_DATA(cmsg), iov);
 			if (retval < 0)
 				return retval;
 			size += retval;
@@ -951,10 +972,11 @@ static int rds_cmsg_zcopy(struct rds_sock *rs, struct rds_message *rm,
 }
 
 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
-			 struct msghdr *msg, int *allocated_mr)
+			 struct msghdr *msg, int *allocated_mr,
+			 struct rds_iov_vector_arr *vct)
 {
 	struct cmsghdr *cmsg;
-	int ret = 0;
+	int ret = 0, ind = 0;
 
 	for_each_cmsghdr(cmsg, msg) {
 		if (!CMSG_OK(msg, cmsg))
@@ -968,7 +990,10 @@ static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 		 */
 		switch (cmsg->cmsg_type) {
 		case RDS_CMSG_RDMA_ARGS:
-			ret = rds_cmsg_rdma_args(rs, rm, cmsg);
+			if (ind >= vct->indx)
+				return -ENOMEM;
+			ret = rds_cmsg_rdma_args(rs, rm, cmsg, &vct->vec[ind]);
+			ind++;
 			break;
 
 		case RDS_CMSG_RDMA_DEST:
@@ -1084,6 +1109,11 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
 		      sock_flag(rds_rs_to_sk(rs), SOCK_ZEROCOPY));
 	int num_sgs = ceil(payload_len, PAGE_SIZE);
 	int namelen;
+	struct rds_iov_vector_arr vct = {0};
+	int ind;
+
+	/* expect 1 RDMA CMSG per rds_sendmsg. can still grow if more needed. */
+	vct.incr = 1;
 
 	/* Mirror Linux UDP mirror of BSD error message compatibility */
 	/* XXX: Perhaps MSG_MORE someday */
@@ -1220,7 +1250,7 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
 		num_sgs = iov_iter_npages(&msg->msg_iter, INT_MAX);
 	}
 	/* size of rm including all sgs */
-	ret = rds_rm_size(msg, num_sgs);
+	ret = rds_rm_size(msg, num_sgs, &vct);
 	if (ret < 0)
 		goto out;
 
@@ -1232,11 +1262,9 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
 
 	/* Attach data to the rm */
 	if (payload_len) {
-		rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
-		if (!rm->data.op_sg) {
-			ret = -ENOMEM;
+		rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs, &ret);
+		if (!rm->data.op_sg)
 			goto out;
-		}
 		ret = rds_message_copy_from_user(rm, &msg->msg_iter, zcopy);
 		if (ret)
 			goto out;
@@ -1270,7 +1298,7 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
 	rm->m_conn_path = cpath;
 
 	/* Parse any control messages the user may have included. */
-	ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
+	ret = rds_cmsg_send(rs, rm, msg, &allocated_mr, &vct);
 	if (ret) {
 		/* Trigger connection so that its ready for the next retry */
 		if (ret ==  -EAGAIN)
@@ -1348,9 +1376,18 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
 	if (ret)
 		goto out;
 	rds_message_put(rm);
+
+	for (ind = 0; ind < vct.indx; ind++)
+		kfree(vct.vec[ind].iov);
+	kfree(vct.vec);
+
 	return payload_len;
 
 out:
+	for (ind = 0; ind < vct.indx; ind++)
+		kfree(vct.vec[ind].iov);
+	kfree(vct.vec);
+
 	/* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
 	 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
 	 * or in any other way, we need to destroy the MR again */