| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.12 004/127] habanalabs/gaudi: Fix a potential use after free in gaudi_memset_device_memory | Date | Mon, 24 May 2021 17:25:21 +0200 |
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From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
[ Upstream commit 115726c5d312b462c9d9931ea42becdfa838a076 ]
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: 423815bf02e25 ("habanalabs/gaudi: remove PCI access to SM block") Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> Reviewed-by: Oded Gabbay <ogabbay@kernel.org> Signed-off-by: Oded Gabbay <ogabbay@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/misc/habanalabs/gaudi/gaudi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/misc/habanalabs/gaudi/gaudi.c b/drivers/misc/habanalabs/gaudi/gaudi.c index 9152242778f5..ecdedd87f8cc 100644 --- a/drivers/misc/habanalabs/gaudi/gaudi.c +++ b/drivers/misc/habanalabs/gaudi/gaudi.c @@ -5546,6 +5546,7 @@ 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); @@ -5612,8 +5613,9 @@ 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; } -- 2.30.2
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