On Tue, Feb 08, 2022 at 04:05:31PM -0400, Jason Gunthorpe wrote:
> If the state is not idle then resolve_prepare_src() 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)
>
> 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 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.
>
> Also, src_addr is never NULL in cma_bind_addr().
>
> This is similar to commit bc0bdc5afaa7 ("RDMA/cma: Do not change
> route.addr.src_addr.ss_family")
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 732d41c545bb ("RDMA/cma: Make the locking for automatic state transition more clear")
> Reported-by: syzbot+c94a3675a626f6333d74@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> ---
> drivers/infiniband/core/cma.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index 27a00ce2e10120..f9b7b6f0703f58 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -3368,20 +3368,24 @@ static int cma_resolve_ib_addr(struct rdma_id_private *id_priv)
> 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;
> + struct sockaddr_storage zero_sock = {};
> +
> + if (!src_addr->sa_family) {
You removed !src_addr check and it will cause to crash for SRP flow,
as it passes NULL in srp_new_rdma_cm_id() function.
334 static int srp_new_rdma_cm_id(struct srp_rdma_ch *ch)
....
349 ret = rdma_resolve_addr(new_cm_id, target->rdma_cm.src_specified ?
350 &target->rdma_cm.src.sa : NULL,
351 &target->rdma_cm.dst.sa,
352 SRP_PATH_REC_TIMEOUT_MS);
....
3421 int rdma_resolve_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,
3422 const struct sockaddr *dst_addr, unsigned long timeout_ms)
3423 {
....
3428 ret = resolve_prepare_src(id_priv, src_addr, dst_addr);
....
3389 static int resolve_prepare_src(struct rdma_id_private *id_priv,
3390 struct sockaddr *src_addr,
3391 const struct sockaddr *dst_addr)
3392 {
....
3362 static int cma_bind_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,
3363 const struct sockaddr *dst_addr)
Maybe it is not possible to do not have src_addr in this stage, but it
is not clear from the code.
Thanks
> + 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 *) src_addr;
> + 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 *) src_addr)->sib_pkey =
> - ((struct sockaddr_ib *) dst_addr)->sib_pkey;
> + ((struct sockaddr_ib *)&zero_sock)->sib_pkey =
> + ((struct sockaddr_ib *)dst_addr)->sib_pkey;
> }
> + src_addr = (struct sockaddr *)&zero_sock;
> }
> return rdma_bind_addr(id, src_addr);
> }
>
> base-commit: 2f1b2820b546c1eef07d15ed73db4177c0cf6d46
> --
> 2.35.1
>
