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f0483044c1
Make sure that even in error situations we do not use copy_to_user on uninitialized kernel memory. Cc: stable@vger.kernel.org # 3.19+ Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
115 lines
2.4 KiB
C
115 lines
2.4 KiB
C
/*
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* Access to PCI I/O memory from user space programs.
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*
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* Copyright IBM Corp. 2014
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* Author(s): Alexey Ishchuk <aishchuk@linux.vnet.ibm.com>
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*/
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#include <linux/kernel.h>
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#include <linux/syscalls.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/errno.h>
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#include <linux/pci.h>
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static long get_pfn(unsigned long user_addr, unsigned long access,
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unsigned long *pfn)
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{
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struct vm_area_struct *vma;
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long ret;
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down_read(¤t->mm->mmap_sem);
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ret = -EINVAL;
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vma = find_vma(current->mm, user_addr);
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if (!vma)
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goto out;
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ret = -EACCES;
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if (!(vma->vm_flags & access))
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goto out;
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ret = follow_pfn(vma, user_addr, pfn);
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out:
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up_read(¤t->mm->mmap_sem);
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return ret;
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}
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SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
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const void __user *, user_buffer, size_t, length)
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{
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u8 local_buf[64];
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void __iomem *io_addr;
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void *buf;
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unsigned long pfn;
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long ret;
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if (!zpci_is_enabled())
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return -ENODEV;
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if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
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return -EINVAL;
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if (length > 64) {
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buf = kmalloc(length, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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} else
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buf = local_buf;
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ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
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if (ret)
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goto out;
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io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
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ret = -EFAULT;
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if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
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goto out;
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if (copy_from_user(buf, user_buffer, length))
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goto out;
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ret = zpci_memcpy_toio(io_addr, buf, length);
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out:
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if (buf != local_buf)
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kfree(buf);
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return ret;
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}
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SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
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void __user *, user_buffer, size_t, length)
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{
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u8 local_buf[64];
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void __iomem *io_addr;
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void *buf;
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unsigned long pfn;
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long ret;
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if (!zpci_is_enabled())
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return -ENODEV;
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if (length <= 0 || PAGE_SIZE - (mmio_addr & ~PAGE_MASK) < length)
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return -EINVAL;
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if (length > 64) {
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buf = kmalloc(length, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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} else
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buf = local_buf;
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ret = get_pfn(mmio_addr, VM_READ, &pfn);
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if (ret)
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goto out;
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io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
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if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
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ret = -EFAULT;
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goto out;
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}
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ret = zpci_memcpy_fromio(buf, io_addr, length);
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if (ret)
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goto out;
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if (copy_to_user(user_buffer, buf, length))
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ret = -EFAULT;
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out:
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if (buf != local_buf)
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kfree(buf);
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return ret;
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}
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