Messages in this thread | | | From | Oded Gabbay <> | Date | Sat, 8 May 2021 11:34:14 +0300 | Subject | Re: [PATCH] habanalabs/gaudi: Fix a potential use after free in gaudi_memset_device_memory |
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On Mon, Apr 26, 2021 at 4:44 PM Lv Yunlong <lyl2019@mail.ustc.edu.cn> wrote: > > 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> > --- > 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; > } > -- > 2.25.1 > > Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Thanks for catching this. Applied to -fixes. Oded
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