[PATCH AUTOSEL 5.3 19/33] net/rds: Whitelist rdma_cookie and rx_tstamp for usercopy

Sasha Levin
2019-10-25T13:55:50Z

From: Dag Moxnes <dag.moxnes@oracle.com>

[ Upstream commit bf1867db9b850fff2dd54a1a117a684a10b8cd90 ]

Add the RDMA cookie and RX timestamp to the usercopy whitelist.

After the introduction of hardened usercopy whitelisting
(https://lwn.net/Articles/727322/), a warning is displayed when the
RDMA cookie or RX timestamp is copied to userspace:

kernel: WARNING: CPU: 3 PID: 5750 at
mm/usercopy.c:81 usercopy_warn+0x8e/0xa6
[...]
kernel: Call Trace:
kernel: __check_heap_object+0xb8/0x11b
kernel: __check_object_size+0xe3/0x1bc
kernel: put_cmsg+0x95/0x115
kernel: rds_recvmsg+0x43d/0x620 [rds]
kernel: sock_recvmsg+0x43/0x4a
kernel: ___sys_recvmsg+0xda/0x1e6
kernel: ? __handle_mm_fault+0xcae/0xf79
kernel: __sys_recvmsg+0x51/0x8a
kernel: SyS_recvmsg+0x12/0x1c
kernel: do_syscall_64+0x79/0x1ae

When the whitelisting feature was introduced, the memory for the RDMA
cookie and RX timestamp in RDS was not added to the whitelist, causing
the warning above.

Signed-off-by: Dag Moxnes <dag.moxnes@oracle.com>
Tested-by: Jenny <jenny.x.xu@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/rds/ib_recv.c | 11 ++++++++---
net/rds/rds.h | 9 +++++++--
net/rds/recv.c | 22 ++++++++++++----------
3 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 3cae88cbdaa02..fecd0abdc7e8e 100644
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -1038,9 +1038,14 @@ int rds_ib_recv_init(void)
si_meminfo(&si);
rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;

- rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
- sizeof(struct rds_ib_incoming),
- 0, SLAB_HWCACHE_ALIGN, NULL);
+ rds_ib_incoming_slab =
+ kmem_cache_create_usercopy("rds_ib_incoming",
+ sizeof(struct rds_ib_incoming),
+ 0, SLAB_HWCACHE_ALIGN,
+ offsetof(struct rds_ib_incoming,
+ ii_inc.i_usercopy),
+ sizeof(struct rds_inc_usercopy),
+ NULL);
if (!rds_ib_incoming_slab)
goto out;

diff --git a/net/rds/rds.h b/net/rds/rds.h
index f0066d1684993..e792a67dd5788 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -271,6 +271,12 @@ struct rds_ext_header_rdma_dest {
#define RDS_MSG_RX_END 2
#define RDS_MSG_RX_CMSG 3

+/* The following values are whitelisted for usercopy */
+struct rds_inc_usercopy {
+ rds_rdma_cookie_t rdma_cookie;
+ ktime_t rx_tstamp;
+};
+
struct rds_incoming {
refcount_t i_refcount;
struct list_head i_item;
@@ -280,8 +286,7 @@ struct rds_incoming {
unsigned long i_rx_jiffies;
struct in6_addr i_saddr;

- rds_rdma_cookie_t i_rdma_cookie;
- ktime_t i_rx_tstamp;
+ struct rds_inc_usercopy i_usercopy;
u64 i_rx_lat_trace[RDS_RX_MAX_TRACES];
};

diff --git a/net/rds/recv.c b/net/rds/recv.c
index a42ba7fa06d5d..c8404971d5ab3 100644
--- a/net/rds/recv.c
+++ b/net/rds/recv.c
@@ -47,8 +47,8 @@ void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
INIT_LIST_HEAD(&inc->i_item);
inc->i_conn = conn;
inc->i_saddr = *saddr;
- inc->i_rdma_cookie = 0;
- inc->i_rx_tstamp = ktime_set(0, 0);
+ inc->i_usercopy.rdma_cookie = 0;
+ inc->i_usercopy.rx_tstamp = ktime_set(0, 0);

memset(inc->i_rx_lat_trace, 0, sizeof(inc->i_rx_lat_trace));
}
@@ -62,8 +62,8 @@ void rds_inc_path_init(struct rds_incoming *inc, struct rds_conn_path *cp,
inc->i_conn = cp->cp_conn;
inc->i_conn_path = cp;
inc->i_saddr = *saddr;
- inc->i_rdma_cookie = 0;
- inc->i_rx_tstamp = ktime_set(0, 0);
+ inc->i_usercopy.rdma_cookie = 0;
+ inc->i_usercopy.rx_tstamp = ktime_set(0, 0);
}
EXPORT_SYMBOL_GPL(rds_inc_path_init);

@@ -186,7 +186,7 @@ static void rds_recv_incoming_exthdrs(struct rds_incoming *inc, struct rds_sock
case RDS_EXTHDR_RDMA_DEST:
/* We ignore the size for now. We could stash it
* somewhere and use it for error checking. */
- inc->i_rdma_cookie = rds_rdma_make_cookie(
+ inc->i_usercopy.rdma_cookie = rds_rdma_make_cookie(
be32_to_cpu(buffer.rdma_dest.h_rdma_rkey),
be32_to_cpu(buffer.rdma_dest.h_rdma_offset));

@@ -380,7 +380,7 @@ void rds_recv_incoming(struct rds_connection *conn, struct in6_addr *saddr,
be32_to_cpu(inc->i_hdr.h_len),
inc->i_hdr.h_dport);
if (sock_flag(sk, SOCK_RCVTSTAMP))
- inc->i_rx_tstamp = ktime_get_real();
+ inc->i_usercopy.rx_tstamp = ktime_get_real();
rds_inc_addref(inc);
inc->i_rx_lat_trace[RDS_MSG_RX_END] = local_clock();
list_add_tail(&inc->i_item, &rs->rs_recv_queue);
@@ -540,16 +540,18 @@ static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg,
{
int ret = 0;

- if (inc->i_rdma_cookie) {
+ if (inc->i_usercopy.rdma_cookie) {
ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
- sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
+ sizeof(inc->i_usercopy.rdma_cookie),
+ &inc->i_usercopy.rdma_cookie);
if (ret)
goto out;
}

- if ((inc->i_rx_tstamp != 0) &&
+ if ((inc->i_usercopy.rx_tstamp != 0) &&
sock_flag(rds_rs_to_sk(rs), SOCK_RCVTSTAMP)) {
- struct __kernel_old_timeval tv = ns_to_kernel_old_timeval(inc->i_rx_tstamp);
+ struct __kernel_old_timeval tv =
+ ns_to_kernel_old_timeval(inc->i_usercopy.rx_tstamp);

if (!sock_flag(rds_rs_to_sk(rs), SOCK_TSTAMP_NEW)) {
ret = put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP_OLD,
--
2.20.1