On Mon, May 23, 2022 at 05:20:33PM +0200, Greg KH wrote:
On Mon, May 23, 2022 at 02:40:08PM +0300, Ovidiu Panait wrote:
From: Linus Torvalds torvalds@linux-foundation.org
commit 901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544 upstream.
Halil Pasic points out [1] that the full revert of that commit (revert in bddac7c1e02b), and that a partial revert that only reverts the problematic case, but still keeps some of the cleanups is probably better. 
And that partial revert [2] had already been verified by Oleksandr Natalenko to also fix the issue, I had just missed that in the long discussion.
So let's reinstate the cleanups from commit aa6f8dcbab47 ("swiotlb: rework "fix info leak with DMA_FROM_DEVICE""), and effectively only revert the part that caused problems.
Link: https://lore.kernel.org/all/20220328013731.017ae3e3.pasic@linux.ibm.com/ [1] Link: https://lore.kernel.org/all/20220324055732.GB12078@lst.de/ [2] Link: https://lore.kernel.org/all/4386660.LvFx2qVVIh@natalenko.name/ [3] Suggested-by: Halil Pasic pasic@linux.ibm.com Tested-by: Oleksandr Natalenko oleksandr@natalenko.name Cc: Christoph Hellwig hch@lst.de Signed-off-by: Linus Torvalds torvalds@linux-foundation.org [OP: backport to 5.10: adjusted context] Signed-off-by: Ovidiu Panait ovidiu.panait@windriver.com
This is part of CVE-2022-0854 patchset: [1] ddbd89deb7d3 ("swiotlb: fix info leak with DMA_FROM_DEVICE") [2] 901c7280ca0d ("Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE""")
[1] is already present in 5.10-stable. [2] is present in 5.17/5.16/5.15, but not in 5.10 and 5.4 branches;
Documentation/core-api/dma-attributes.rst | 8 -------- include/linux/dma-mapping.h | 8 -------- kernel/dma/swiotlb.c | 12 ++++++++---- 3 files changed, 8 insertions(+), 20 deletions(-)
This looks much different than the backport Sasha did. I'll drop his and review all of this after this next round of -rc releases go out.
Nevermind, Sasha's backport looks to match this one, it was just spread over 2 commits, so I'll leave it.
thanks,
greg k-h