Messages in this thread | | | Date | Wed, 1 Nov 2023 10:50:22 +0530 | Subject | Re: [PATCH v2] bus: mhi: host: Add alignment check for event ring read pointer | From | Krishna Chaitanya Chundru <> |
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On 11/1/2023 10:47 AM, Manivannan Sadhasivam wrote: > On Tue, Oct 31, 2023 at 03:21:05PM +0530, Krishna chaitanya chundru wrote: >> 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> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > > Bjorn gave his R-b tag for v1 and you didn't include it. If you dropped it on > purpose, then you should mention it in the "Changes" along with a justification. > > - Mani
As there is change in the logic I didn't include the tag. I will mention this on the next patch.
- Krishna Chaitanya.
>> --- >> 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> >>
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