From: Nicolin Chen Date: Mon, 20 Jan 2025 19:50:51 +0000 (-0800) Subject: iommufd: Fix struct iommu_hwpt_pgfault init and padding X-Git-Tag: v6.12.14~113 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7caf6c4bc25ac6cf588c6ceacba7ee4a15f81f8b;p=thirdparty%2Fkernel%2Fstable.git iommufd: Fix struct iommu_hwpt_pgfault init and padding commit e721f619e3ec9bae08bf419c3944cf1e6966c821 upstream. The iommu_hwpt_pgfault is used to report IO page fault data to userspace, but iommufd_fault_fops_read was never zeroing its padding. This leaks the content of the kernel stack memory to userspace. Also, the iommufd uAPI requires explicit padding and use of __aligned_u64 to ensure ABI compatibility's with 32 bit. pahole result, before: struct iommu_hwpt_pgfault { __u32 flags; /* 0 4 */ __u32 dev_id; /* 4 4 */ __u32 pasid; /* 8 4 */ __u32 grpid; /* 12 4 */ __u32 perm; /* 16 4 */ /* XXX 4 bytes hole, try to pack */ __u64 addr; /* 24 8 */ __u32 length; /* 32 4 */ __u32 cookie; /* 36 4 */ /* size: 40, cachelines: 1, members: 8 */ /* sum members: 36, holes: 1, sum holes: 4 */ /* last cacheline: 40 bytes */ }; pahole result, after: struct iommu_hwpt_pgfault { __u32 flags; /* 0 4 */ __u32 dev_id; /* 4 4 */ __u32 pasid; /* 8 4 */ __u32 grpid; /* 12 4 */ __u32 perm; /* 16 4 */ __u32 __reserved; /* 20 4 */ __u64 addr __attribute__((__aligned__(8))); /* 24 8 */ __u32 length; /* 32 4 */ __u32 cookie; /* 36 4 */ /* size: 40, cachelines: 1, members: 9 */ /* forced alignments: 1 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); Fixes: c714f15860fc ("iommufd: Add fault and response message definitions") Link: https://patch.msgid.link/r/20250120195051.2450-1-nicolinc@nvidia.com Cc: stable@vger.kernel.org Reviewed-by: Jason Gunthorpe Signed-off-by: Nicolin Chen Reviewed-by: Kevin Tian Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/iommu/iommufd/fault.c b/drivers/iommu/iommufd/fault.c index b8393a8c07539..119b95f149171 100644 --- a/drivers/iommu/iommufd/fault.c +++ b/drivers/iommu/iommufd/fault.c @@ -242,7 +242,7 @@ static ssize_t iommufd_fault_fops_read(struct file *filep, char __user *buf, { size_t fault_size = sizeof(struct iommu_hwpt_pgfault); struct iommufd_fault *fault = filep->private_data; - struct iommu_hwpt_pgfault data; + struct iommu_hwpt_pgfault data = {}; struct iommufd_device *idev; struct iopf_group *group; struct iopf_fault *iopf; diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index 72010f71c5e47..8c4470742dcd9 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -737,6 +737,7 @@ enum iommu_hwpt_pgfault_perm { * @pasid: Process Address Space ID * @grpid: Page Request Group Index * @perm: Combination of enum iommu_hwpt_pgfault_perm + * @__reserved: Must be 0. * @addr: Fault address * @length: a hint of how much data the requestor is expecting to fetch. For * example, if the PRI initiator knows it is going to do a 10MB @@ -752,7 +753,8 @@ struct iommu_hwpt_pgfault { __u32 pasid; __u32 grpid; __u32 perm; - __u64 addr; + __u32 __reserved; + __aligned_u64 addr; __u32 length; __u32 cookie; };