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: v6.14-rc1~107^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e721f619e3ec9bae08bf419c3944cf1e6966c821;p=thirdparty%2Flinux.git iommufd: Fix struct iommu_hwpt_pgfault init and padding 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 --- diff --git a/drivers/iommu/iommufd/fault.c b/drivers/iommu/iommufd/fault.c index a9160f4443d28..d9a937450e552 100644 --- a/drivers/iommu/iommufd/fault.c +++ b/drivers/iommu/iommufd/fault.c @@ -263,7 +263,7 @@ 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 34810f6ae2b5a..78747b24bd0fb 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -868,6 +868,7 @@ 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 @@ -883,7 +884,8 @@ struct iommu_hwpt_pgfault { __u32 pasid; __u32 grpid; __u32 perm; - __u64 addr; + __u32 __reserved; + __aligned_u64 addr; __u32 length; __u32 cookie; };