[PATCH for-rc] RDMA/srpt: Fix UAF when srpt_add_one() failed

Junxian Huang
2024-08-01T07:49:53Z

Currently cancel_work_sync() is not called when srpt_refresh_port()
failed in srpt_add_one(). There is a probability that sdev has been
freed while the previously initiated sport->work is still running,
leading to a UAF as the log below:

[ T880] ib_srpt MAD registration failed for hns_1-1.
[ T880] ib_srpt srpt_add_one(hns_1) failed.
[ T376] Unable to handle kernel paging request at virtual address 0000000000010008
...
[ T376] Workqueue: events srpt_refresh_port_work [ib_srpt]
...
[ T376] Call trace:
[ T376] srpt_refresh_port+0x94/0x264 [ib_srpt]
[ T376] srpt_refresh_port_work+0x1c/0x2c [ib_srpt]
[ T376] process_one_work+0x1d8/0x4cc
[ T376] worker_thread+0x158/0x410
[ T376] kthread+0x108/0x13c
[ T376] ret_from_fork+0x10/0x18

Add cancel_work_sync() to the exception branch to fix this UAF.

Fixes: a42d985bd5b2 ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
---
drivers/infiniband/ulp/srpt/ib_srpt.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 9632afbd727b..244e5c115bf7 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -3148,8 +3148,8 @@ static int srpt_add_one(struct ib_device *device)
{
struct srpt_device *sdev;
struct srpt_port *sport;
+ u32 i, j;
int ret;
- u32 i;

pr_debug("device = %p\n", device);

@@ -3226,7 +3226,6 @@ static int srpt_add_one(struct ib_device *device)
if (ret) {
pr_err("MAD registration failed for %s-%d.\n",
dev_name(&sdev->device->dev), i);
- i--;
goto err_port;
}
}
@@ -3241,6 +3240,8 @@ static int srpt_add_one(struct ib_device *device)
return 0;

err_port:
+ for (j = i, i--; j > 0; j--)
+ cancel_work_sync(&sdev->port[j - 1].work);
srpt_unregister_mad_agent(sdev, i);
err_cm:
if (sdev->cm_id)
--
2.33.0