From: shamir rabinovitch <shamir.rabinovi...@oracle.com> per comment from Leon in rdma mailing list https://lkml.org/lkml/2018/10/31/312 :
Please don't forget to remove user triggered WARN_ON. https://lwn.net/Articles/769365/ "Greg Kroah-Hartman raised the problem of core kernel API code that will use WARN_ON_ONCE() to complain about bad usage; that will not generate the desired result if WARN_ON_ONCE() is configured to crash the machine. He was told that the code should just call pr_warn() instead, and that the called function should return an error in such situations. It was generally agreed that any WARN_ON() or WARN_ON_ONCE() calls that can be triggered from user space need to be fixed." in addition harden rds_sendmsg to detect and overcome issues with invalid sg count and fail the sendmsg. Suggested-by: Leon Romanovsky <l...@kernel.org> Acked-by: Santosh Shilimkar <santosh.shilim...@oracle.com> Signed-off-by: shamir rabinovitch <shamir.rabinovi...@oracle.com> --- net/rds/message.c | 24 ++++++++++++++++++------ net/rds/rdma.c | 12 ++++-------- net/rds/rds.h | 3 ++- net/rds/send.c | 9 +++++---- 4 files changed, 29 insertions(+), 19 deletions(-) diff --git a/net/rds/message.c b/net/rds/message.c index 4b00b1152a5f..f139420ba1f6 100644 --- a/net/rds/message.c +++ b/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) { diff --git a/net/rds/rdma.c b/net/rds/rdma.c index e1965d9cbcf8..182ab8430594 100644 --- a/net/rds/rdma.c +++ b/net/rds/rdma.c @@ -623,11 +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; + 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 @@ -839,11 +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) { diff --git a/net/rds/rds.h b/net/rds/rds.h index 4d2523100093..02ec4a3b2799 100644 --- a/net/rds/rds.h +++ b/net/rds/rds.h @@ -839,7 +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); diff --git a/net/rds/send.c b/net/rds/send.c index ec2267cbf85f..b39b30706210 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -886,6 +886,9 @@ static int rds_rm_size(struct msghdr *msg, int num_sgs, 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)) return -EINVAL; @@ -1259,11 +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; -- 2.19.1
