This is a note to let you know that I've just added the patch titled
habanalabs/gaudi: Fix a potential use after free in gaudi_memset_device_memory
to the 5.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
habanalabs-gaudi-fix-a-potential-use-after-free-in-g.patch
and it can be found in the queue-5.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 78f96b4733e432f87b2e20c63da71118a10df7cd
Author: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
Date: Mon Apr 26 06:43:46 2021 -0700
habanalabs/gaudi: Fix a potential use after free in gaudi_memset_device_memory
[ 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@xxxxxxxxxxxxxxxx>
Reviewed-by: Oded Gabbay <ogabbay@xxxxxxxxxx>
Signed-off-by: Oded Gabbay <ogabbay@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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;
}
