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authorAndy Grover <andy.grover@oracle.com>2010-10-28 15:40:59 +0000
committerDavid S. Miller <davem@davemloft.net>2010-10-30 16:34:18 -0700
commitd139ff0907dac9ef72fb2cf301e345bac3aec42f (patch)
tree0ba63235a10b7640bc8b613da0d0cda220a55087
parentfc8162e3c034af743d8def435fda6396603d321f (diff)
downloadlinux-linaro-d139ff0907dac9ef72fb2cf301e345bac3aec42f.tar.gz
RDS: Let rds_message_alloc_sgs() return NULL
Even with the previous fix, we still are reading the iovecs once to determine SGs needed, and then again later on. Preallocating space for sg lists as part of rds_message seemed like a good idea but it might be better to not do this. While working to redo that code, this patch attempts to protect against userspace rewriting the rds_iovec array between the first and second accesses. The consequences of this would be either a too-small or too-large sg list array. Too large is not an issue. This patch changes all callers of message_alloc_sgs to handle running out of preallocated sgs, and fail gracefully. Signed-off-by: Andy Grover <andy.grover@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/rds/message.c5
-rw-r--r--net/rds/rdma.c8
-rw-r--r--net/rds/send.c4
3 files changed, 17 insertions, 0 deletions
diff --git a/net/rds/message.c b/net/rds/message.c
index a84545dae37..848cff45183 100644
--- a/net/rds/message.c
+++ b/net/rds/message.c
@@ -224,6 +224,9 @@ struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
WARN_ON(rm->m_used_sgs + nents > rm->m_total_sgs);
WARN_ON(!nents);
+ if (rm->m_used_sgs + nents > rm->m_total_sgs)
+ return NULL;
+
sg_ret = &sg_first[rm->m_used_sgs];
sg_init_table(sg_ret, nents);
rm->m_used_sgs += nents;
@@ -246,6 +249,8 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in
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);
+ if (!rm->data.op_sg)
+ return ERR_PTR(-ENOMEM);
for (i = 0; i < rm->data.op_nents; ++i) {
sg_set_page(&rm->data.op_sg[i],
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index caa4d9866d9..8920f2a8332 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -607,6 +607,10 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
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;
+ }
if (op->op_notify || op->op_recverr) {
/* We allocate an uninitialized notifier here, because
@@ -807,6 +811,10 @@ int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
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;
+ goto err;
+ }
/* verify 8 byte-aligned */
if (args->local_addr & 0x7) {
diff --git a/net/rds/send.c b/net/rds/send.c
index 0bc9db17a87..35b9c2e9caf 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -973,6 +973,10 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
/* Attach data to the rm */
if (payload_len) {
rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
+ if (!rm->data.op_sg) {
+ ret = -ENOMEM;
+ goto out;
+ }
ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
if (ret)
goto out;