Commit 115726c5 authored by Lv Yunlong's avatar Lv Yunlong Committed by Oded Gabbay
Browse files

habanalabs/gaudi: Fix a potential use after free in gaudi_memset_device_memory 



Our code analyzer reported a uaf.

In gaudi_memset_device_memory, cb is get via hl_cb_kernel_create()
with 2 refcount.
If hl_cs_allocate_job() failed, the execution runs into release_cb
branch. One ref of cb is dropped by hl_cb_put(cb) and could be freed
if other thread also drops one ref. Then cb is used by cb->id later,
which is a potential uaf.

My patch add a variable 'id' to accept the value of cb->id before the
hl_cb_put(cb) is called, to avoid the potential uaf.

Fixes: 423815bf ("habanalabs/gaudi: remove PCI access to SM block")
Signed-off-by: default avatarLv Yunlong <lyl2019@mail.ustc.edu.cn>
Reviewed-by: default avatarOded Gabbay <ogabbay@kernel.org>
Signed-off-by: default avatarOded Gabbay <ogabbay@kernel.org>
parent 24a10709

drivers/misc/habanalabs/gaudi/gaudi.c

+3 −1
Original line number Diff line number Diff line
@@ -5579,6 +5579,7 @@ static int gaudi_memset_device_memory(struct hl_device *hdev, u64 addr, 
	struct hl_cs_job *job;

	u32 cb_size, ctl, err_cause;

	struct hl_cb *cb;

	u64 id;

	int rc;



	cb = hl_cb_kernel_create(hdev, PAGE_SIZE, false);
@@ -5645,8 +5646,9 @@ static int gaudi_memset_device_memory(struct hl_device *hdev, u64 addr, 
	}



release_cb:

	id = cb->id;

	hl_cb_put(cb);

	hl_cb_destroy(hdev, &hdev->kernel_cb_mgr, cb->id << PAGE_SHIFT);

	hl_cb_destroy(hdev, &hdev->kernel_cb_mgr, id << PAGE_SHIFT);



	return rc;

}