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* [PATCH v2] bus: mhi: host: Add alignment check for event ring read pointer
@ 2023-10-31  9:51 Krishna chaitanya chundru
  2023-11-01  5:17 ` Manivannan Sadhasivam
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Krishna chaitanya chundru @ 2023-10-31  9:51 UTC (permalink / raw)
  To: Manivannan Sadhasivam
  Cc: mhi, linux-arm-msm, linux-kernel, quic_vbadigan, quic_ramkri,
	quic_skananth, quic_parass, stable, Krishna chaitanya chundru

Though we do check the event ring read pointer by "is_valid_ring_ptr"
to make sure it is in the buffer range, but there is another risk the
pointer may be not aligned.  Since we are expecting event ring elements
are 128 bits(struct mhi_ring_element) aligned, an unaligned read pointer
could lead to multiple issues like DoS or ring buffer memory corruption.

So add a alignment check for event ring read pointer.

Fixes: ec32332df764 ("bus: mhi: core: Sanity check values from remote device before use")
cc: stable@vger.kernel.org
Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
Changes in v2:
- Change the modulus operation to bit-wise & operation as suggested by Jeff.
- Link to v1: https://lore.kernel.org/r/20231023-alignment_check-v1-1-2ca5716d5c15@quicinc.com
---
 drivers/bus/mhi/host/main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index 499590437e9b..e765c16a99d1 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -268,7 +268,8 @@ static void mhi_del_ring_element(struct mhi_controller *mhi_cntrl,
 
 static bool is_valid_ring_ptr(struct mhi_ring *ring, dma_addr_t addr)
 {
-	return addr >= ring->iommu_base && addr < ring->iommu_base + ring->len;
+	return addr >= ring->iommu_base && addr < ring->iommu_base + ring->len &&
+			!(addr & (sizeof(struct mhi_ring_element) - 1));
 }
 
 int mhi_destroy_device(struct device *dev, void *data)

---
base-commit: 71e68e182e382e951d6248bccc3c960dcec5a718
change-id: 20231013-alignment_check-c013f509d24a

Best regards,
-- 
Krishna chaitanya chundru <quic_krichai@quicinc.com>


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2023-11-09 16:35 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2023-10-31  9:51 [PATCH v2] bus: mhi: host: Add alignment check for event ring read pointer Krishna chaitanya chundru
2023-11-01  5:17 ` Manivannan Sadhasivam
2023-11-01  5:20   ` Krishna Chaitanya Chundru
2023-11-03 14:54 ` Jeffrey Hugo
2023-11-05  8:33 ` Manivannan Sadhasivam
2023-11-09 16:34 ` Manivannan Sadhasivam

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