[PATCH 5.10 22/93] RDMA/cma: Do not change route.addr.src_addr.ss_family

Greg Kroah-Hartman
2021-10-04T13:23:24Z

From: Jason Gunthorpe <jgg@nvidia.com>

commit bc0bdc5afaa740d782fbf936aaeebd65e5c2921d upstream.

If the state is not idle then rdma_bind_addr() will immediately fail and
no change to global state should happen.

For instance if the state is already RDMA_CM_LISTEN then this will corrupt
the src_addr and would cause the test in cma_cancel_operation():

if (cma_any_addr(cma_src_addr(id_priv)) && !id_priv->cma_dev)

To view a mangled src_addr, eg with a IPv6 loopback address but an IPv4
family, failing the test.

This would manifest as this trace from syzkaller:

BUG: KASAN: use-after-free in __list_add_valid+0x93/0xa0 lib/list_debug.c:26
Read of size 8 at addr ffff8881546491e0 by task syz-executor.1/32204

CPU: 1 PID: 32204 Comm: syz-executor.1 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
__kasan_report mm/kasan/report.c:399 [inline]
kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
__list_add_valid+0x93/0xa0 lib/list_debug.c:26
__list_add include/linux/list.h:67 [inline]
list_add_tail include/linux/list.h:100 [inline]
cma_listen_on_all drivers/infiniband/core/cma.c:2557 [inline]
rdma_listen+0x787/0xe00 drivers/infiniband/core/cma.c:3751
ucma_listen+0x16a/0x210 drivers/infiniband/core/ucma.c:1102
ucma_write+0x259/0x350 drivers/infiniband/core/ucma.c:1732
vfs_write+0x28e/0xa30 fs/read_write.c:603
ksys_write+0x1ee/0x250 fs/read_write.c:658
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae

Which is indicating that an rdma_id_private was destroyed without doing
cma_cancel_listens().

Instead of trying to re-use the src_addr memory to indirectly create an
any address build one explicitly on the stack and bind to that as any
other normal flow would do.

Link: https://lore.kernel.org/r/0-v1-9fbb33f5e201+2a-cma_listen_jgg@nvidia.com
Cc: stable@vger.kernel.org
Fixes: 732d41c545bb ("RDMA/cma: Make the locking for automatic state transition more clear")
Reported-by: syzbot+6bb0528b13611047209c@syzkaller.appspotmail.com
Tested-by: Hao Sun <sunhao.th@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/infiniband/core/cma.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -3732,9 +3732,13 @@ int rdma_listen(struct rdma_cm_id *id, i
int ret;

if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_LISTEN)) {
+ struct sockaddr_in any_in = {
+ .sin_family = AF_INET,
+ .sin_addr.s_addr = htonl(INADDR_ANY),
+ };
+
/* For a well behaved ULP state will be RDMA_CM_IDLE */
- id->route.addr.src_addr.ss_family = AF_INET;
- ret = rdma_bind_addr(id, cma_src_addr(id_priv));
+ ret = rdma_bind_addr(id, (struct sockaddr *)&any_in);
if (ret)
return ret;
if (WARN_ON(!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND,