From: Maor Gottlieb <maorg@nvidia.com>
Date: Mon, 12 Oct 2020 07:56:00 +0300
Subject: RDMA/ucma: Fix use after free in destroy id flow
Patch-mainline: v5.10-rc1
Git-commit: c7a198c700763ac89abbb166378f546aeb9afb33
References: bsc#1181147
ucma_free_ctx() should call to __destroy_id() on all the connection requests
that have not been delivered to user space. Currently it calls on the
context itself and cause to use after free.
Fixes the trace:
BUG: Unable to handle kernel data access on write at 0x5deadbeef0000108
Faulting instruction address: 0xc0080000002428f4
Oops: Kernel access of bad area, sig: 11 [#1]
Call Trace:
[c000000207f2b680] [c00800000024280c] .__destroy_id+0x28c/0x610 [rdma_ucm] (unreliable)
[c000000207f2b750] [c0080000002429c4] .__destroy_id+0x444/0x610 [rdma_ucm]
[c000000207f2b820] [c008000000242c24] .ucma_close+0x94/0xf0 [rdma_ucm]
[c000000207f2b8c0] [c00000000046fbdc] .__fput+0xac/0x330
[c000000207f2b960] [c00000000015d48c] .task_work_run+0xbc/0x110
[c000000207f2b9f0] [c00000000012fb00] .do_exit+0x430/0xc50
[c000000207f2bae0] [c0000000001303ec] .do_group_exit+0x5c/0xd0
[c000000207f2bb70] [c000000000144a34] .get_signal+0x194/0xe30
[c000000207f2bc60] [c00000000001f6b4] .do_notify_resume+0x124/0x470
[c000000207f2bd60] [c000000000032484] .interrupt_exit_user_prepare+0x1b4/0x240
[c000000207f2be20] [c000000000010034] interrupt_return+0x14/0x1c0
Rename listen_ctx to conn_req_ctx as the poor name was the cause of this
bug.
Fixes: a1d33b70dbbc ("RDMA/ucma: Rework how new connections are passed through event delivery")
Link: https://lore.kernel.org/r/20201012045600.418271-4-leon@kernel.org
Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/infiniband/core/ucma.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -112,7 +112,7 @@ struct ucma_multicast {
struct ucma_event {
struct ucma_context *ctx;
- struct ucma_context *listen_ctx;
+ struct ucma_context *conn_req_ctx;
struct ucma_multicast *mc;
struct list_head list;
struct rdma_ucm_event_resp resp;
@@ -308,7 +308,7 @@ static int ucma_connect_event_handler(st
uevent = ucma_create_uevent(listen_ctx, event);
if (!uevent)
goto err_alloc;
- uevent->listen_ctx = listen_ctx;
+ uevent->conn_req_ctx = ctx;
uevent->resp.id = ctx->id;
ctx->cm_id->context = ctx;
@@ -535,7 +535,7 @@ static int ucma_free_ctx(struct ucma_con
/* Cleanup events not yet reported to the user. */
mutex_lock(&ctx->file->mut);
list_for_each_entry_safe(uevent, tmp, &ctx->file->event_list, list) {
- if (uevent->ctx == ctx || uevent->listen_ctx == ctx)
+ if (uevent->ctx == ctx || uevent->conn_req_ctx == ctx)
list_move_tail(&uevent->list, &list);
}
list_del(&ctx->list);
@@ -549,8 +549,9 @@ static int ucma_free_ctx(struct ucma_con
*/
list_for_each_entry_safe(uevent, tmp, &list, list) {
list_del(&uevent->list);
- if (uevent->resp.event == RDMA_CM_EVENT_CONNECT_REQUEST)
- __destroy_id(uevent->ctx);
+ if (uevent->resp.event == RDMA_CM_EVENT_CONNECT_REQUEST &&
+ uevent->conn_req_ctx != ctx)
+ __destroy_id(uevent->conn_req_ctx);
kfree(uevent);
}