[PATCH 5.15 121/139] RDMA/cma: Do not change route.addr.src_addr outside state checks

Greg Kroah-Hartman
2022-02-28T17:58:49Z

From: Jason Gunthorpe <jgg@nvidia.com>

commit 22e9f71072fa605cbf033158db58e0790101928d upstream.

If the state is not idle then resolve_prepare_src() should immediately
fail and no change to global state should happen. However, it
unconditionally overwrites the src_addr trying to build a temporary any
address.

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)

Which 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

This 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 derived from the dst build one explicitly on the stack and
bind to that as any other normal flow would do. rdma_bind_addr() will copy
it over the src_addr once it knows the state is valid.

This is similar to commit bc0bdc5afaa7 ("RDMA/cma: Do not change
route.addr.src_addr.ss_family")

Link: https://lore.kernel.org/r/0-v2-e975c8fd9ef2+11e-syz_cma_srcaddr_jgg@nvidia.com
Cc: stable@vger.kernel.org
Fixes: 732d41c545bb ("RDMA/cma: Make the locking for automatic state transition more clear")
Reported-by: syzbot+c94a3675a626f6333d74@syzkaller.appspotmail.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 | 38 +++++++++++++++++++++++---------------
1 file changed, 23 insertions(+), 15 deletions(-)

--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -3368,22 +3368,30 @@ err:
static int cma_bind_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,
const struct sockaddr *dst_addr)
{
- if (!src_addr || !src_addr->sa_family) {
- src_addr = (struct sockaddr *) &id->route.addr.src_addr;
- src_addr->sa_family = dst_addr->sa_family;
- if (IS_ENABLED(CONFIG_IPV6) &&
- dst_addr->sa_family == AF_INET6) {
- struct sockaddr_in6 *src_addr6 = (struct sockaddr_in6 *) src_addr;
- struct sockaddr_in6 *dst_addr6 = (struct sockaddr_in6 *) dst_addr;
- src_addr6->sin6_scope_id = dst_addr6->sin6_scope_id;
- if (ipv6_addr_type(&dst_addr6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
- id->route.addr.dev_addr.bound_dev_if = dst_addr6->sin6_scope_id;
- } else if (dst_addr->sa_family == AF_IB) {
- ((struct sockaddr_ib *) src_addr)->sib_pkey =
- ((struct sockaddr_ib *) dst_addr)->sib_pkey;
- }
+ struct sockaddr_storage zero_sock = {};
+
+ if (src_addr && src_addr->sa_family)
+ return rdma_bind_addr(id, src_addr);
+
+ /*
+ * When the src_addr is not specified, automatically supply an any addr
+ */
+ zero_sock.ss_family = dst_addr->sa_family;
+ if (IS_ENABLED(CONFIG_IPV6) && dst_addr->sa_family == AF_INET6) {
+ struct sockaddr_in6 *src_addr6 =
+ (struct sockaddr_in6 *)&zero_sock;
+ struct sockaddr_in6 *dst_addr6 =
+ (struct sockaddr_in6 *)dst_addr;
+
+ src_addr6->sin6_scope_id = dst_addr6->sin6_scope_id;
+ if (ipv6_addr_type(&dst_addr6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
+ id->route.addr.dev_addr.bound_dev_if =
+ dst_addr6->sin6_scope_id;
+ } else if (dst_addr->sa_family == AF_IB) {
+ ((struct sockaddr_ib *)&zero_sock)->sib_pkey =
+ ((struct sockaddr_ib *)dst_addr)->sib_pkey;
}
- return rdma_bind_addr(id, src_addr);
+ return rdma_bind_addr(id, (struct sockaddr *)&zero_sock);
}

/*