From: Nicolin Chen <nicolinc@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: <iommu@lists.linux.dev>, Joerg Roedel <joro@8bytes.org>,
Kevin Tian <kevin.tian@intel.com>,
<linux-kselftest@vger.kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Shuah Khan <shuah@kernel.org>, Will Deacon <will@kernel.org>,
Lixiao Yang <lixiao.yang@intel.com>,
Matthew Rosato <mjrosato@linux.ibm.com>,
<patches@lists.linux.dev>, <stable@vger.kernel.org>,
<syzbot+c2f65e2801743ca64e08@syzkaller.appspotmail.com>,
Yi Liu <yi.l.liu@intel.com>
Subject: Re: [PATCH 1/2] iommufd: Prevent ALIGN() overflow
Date: Fri, 18 Jul 2025 01:16:37 -0700 [thread overview]
Message-ID: <aHoC5c/PSLSZfVXG@Asurada-Nvidia> (raw)
In-Reply-To: <1-v1-7b4a16fc390b+10f4-iommufd_alloc_overflow_jgg@nvidia.com>
On Thu, Jul 17, 2025 at 04:15:08PM -0300, Jason Gunthorpe wrote:
> When allocating IOVA the candidate range gets aligned to the target
> alignment. If the range is close to ULONG_MAX then the ALIGN() can
> wrap resulting in a corrupted iova.
>
> Open code the ALIGN() using get_add_overflow() to prevent this.
> This simplifies the checks as we don't need to check for length earlier
> either.
>
> Consolidate the two copies of this code under a single helper.
>
> This bug would allow userspace to create a mapping that overlaps with some
> other mapping or a reserved range.
>
> Cc: stable@vger.kernel.org
> Fixes: 51fe6141f0f6 ("iommufd: Data structure to provide IOVA to PFN mapping")
> Reported-by: syzbot+c2f65e2801743ca64e08@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/r/685af644.a00a0220.2e5631.0094.GAE@google.com
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
next prev parent reply other threads:[~2025-07-18 8:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-17 19:15 [PATCH 0/2] Fix undetected overflow when allocating IOVA Jason Gunthorpe
2025-07-17 19:15 ` [PATCH 1/2] iommufd: Prevent ALIGN() overflow Jason Gunthorpe
2025-07-18 8:16 ` Nicolin Chen [this message]
2025-07-18 13:03 ` Yi Liu
2025-07-17 19:15 ` [PATCH 2/2] iommufd/selftest: Test reserved regions near ULONG_MAX Jason Gunthorpe
2025-07-18 2:45 ` Nicolin Chen
2025-07-18 8:13 ` Nicolin Chen
2025-07-18 16:21 ` Jason Gunthorpe
2025-07-18 18:23 ` Robin Murphy
2025-07-18 18:50 ` Nicolin Chen
2025-07-18 20:16 ` Jason Gunthorpe
2025-07-18 19:56 ` Jason Gunthorpe
2025-07-18 13:03 ` Yi Liu
2025-07-18 18:10 ` [PATCH 0/2] Fix undetected overflow when allocating IOVA Nicolin Chen
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