From: Nicolin Chen <nicoleotsuka@gmail.com>
To: mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org,
rth@twiddle.net, ink@jurassic.park.msu.ru, mattst88@gmail.com,
tony.luck@intel.com, fenghua.yu@intel.com,
schnelle@linux.ibm.com, gerald.schaefer@linux.ibm.com,
hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com,
davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, x86@kernel.org, hpa@zytor.com,
James.Bottomley@HansenPartnership.com, deller@gmx.de
Cc: sfr@canb.auug.org.au, hch@lst.de, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org, linux-parisc@vger.kernel.org
Subject: [RESEND][PATCH 0/7] Avoid overflow at boundary_size
Date: Mon, 31 Aug 2020 13:38:04 -0700 [thread overview]
Message-ID: <20200831203811.8494-1-nicoleotsuka@gmail.com> (raw)
==== For this resend ====
The original series have not been acked at any patch. So I am
resending them, being suggested by Niklas.
==== Coverletter ====
We are expending the default DMA segmentation boundary to its
possible maximum value (ULONG_MAX) to indicate that a device
doesn't specify a boundary limit. So all dma_get_seg_boundary
callers should take a precaution with the return values since
it would easily get overflowed.
I scanned the entire kernel tree for all the existing callers
and found that most of callers may get overflowed in two ways:
either "+ 1" or passing it to ALIGN() that does "+ mask".
According to kernel defines:
#define ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
#define ALIGN(x, a) ALIGN_MASK(x, (typeof(x))(a) - 1)
We can simplify the logic here:
ALIGN(boundary + 1, 1 << shift) >> shift
= ALIGN_MASK(b + 1, (1 << s) - 1) >> s
= {[b + 1 + (1 << s) - 1] & ~[(1 << s) - 1]} >> s
= [b + 1 + (1 << s) - 1] >> s
= [b + (1 << s)] >> s
= (b >> s) + 1
So this series of patches fix the potential overflow with this
overflow-free shortcut.
As I don't have these platforms, testings/comments are welcome.
Thanks
Nic
Nicolin Chen (7):
powerpc/iommu: Avoid overflow at boundary_size
alpha: Avoid overflow at boundary_size
ia64/sba_iommu: Avoid overflow at boundary_size
s390/pci_dma: Avoid overflow at boundary_size
sparc: Avoid overflow at boundary_size
x86/amd_gart: Avoid overflow at boundary_size
parisc: Avoid overflow at boundary_size
arch/alpha/kernel/pci_iommu.c | 10 ++++------
arch/ia64/hp/common/sba_iommu.c | 4 ++--
arch/powerpc/kernel/iommu.c | 11 +++++------
arch/s390/pci/pci_dma.c | 4 ++--
arch/sparc/kernel/iommu-common.c | 9 +++------
arch/sparc/kernel/iommu.c | 4 ++--
arch/sparc/kernel/pci_sun4v.c | 4 ++--
arch/x86/kernel/amd_gart_64.c | 4 ++--
drivers/parisc/ccio-dma.c | 4 ++--
drivers/parisc/sba_iommu.c | 4 ++--
10 files changed, 26 insertions(+), 32 deletions(-)
--
2.17.1
next reply other threads:[~2020-08-31 20:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 20:38 Nicolin Chen [this message]
2020-08-31 20:38 ` [RESEND][PATCH 1/7] powerpc/iommu: Avoid overflow at boundary_size Nicolin Chen
2020-09-01 13:27 ` Michael Ellerman
2020-09-01 20:53 ` Nicolin Chen
2020-08-31 20:38 ` [RESEND][PATCH 2/7] alpha: " Nicolin Chen
2020-08-31 20:38 ` [RESEND][PATCH 3/7] ia64/sba_iommu: " Nicolin Chen
2020-08-31 20:38 ` [RESEND][PATCH 4/7] s390/pci_dma: " Nicolin Chen
2020-08-31 20:38 ` [RESEND][PATCH 5/7] sparc: " Nicolin Chen
2020-08-31 20:38 ` [RESEND][PATCH 6/7] x86/amd_gart: " Nicolin Chen
2020-08-31 20:38 ` [RESEND][PATCH 7/7] parisc: " Nicolin Chen
2020-09-01 7:36 ` [RESEND][PATCH 0/7] " Christoph Hellwig
2020-09-01 7:54 ` Nicolin Chen
2020-09-01 9:11 ` Christoph Hellwig
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