Messages in this thread Patch in this message | | | Date | Thu, 6 Mar 2008 23:01:47 -0800 | From | Venki Pallipadi <> | Subject | [PATCH] Add range_is_allowed() check to mmap of /dev/mem |
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Earlier patch that introduced CONFIG_NONPROMISC_DEVMEM, did the range_is_allowed() check only for read and write. Add range_is_allowed() check to mmap of /dev/mem as well.
Changes the paramaters of range_is_allowed() to pfn and size to handle more than 32 bits of physical address on 32 bit arch cleanly.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Index: linux-2.6.git/drivers/char/mem.c =================================================================== --- linux-2.6.git.orig/drivers/char/mem.c 2008-03-03 15:29:50.000000000 -0800 +++ linux-2.6.git/drivers/char/mem.c 2008-03-03 15:55:46.000000000 -0800 @@ -109,24 +109,26 @@ #endif #ifdef CONFIG_NONPROMISC_DEVMEM -static inline int range_is_allowed(unsigned long from, unsigned long to) +static inline int range_is_allowed(unsigned long pfn, unsigned long size) { - unsigned long cursor; - - cursor = from >> PAGE_SHIFT; - while ((cursor << PAGE_SHIFT) < to) { - if (!devmem_is_allowed(cursor)) { - printk(KERN_INFO "Program %s tried to read /dev/mem " - "between %lx->%lx.\n", + u64 from = ((u64)pfn) << PAGE_SHIFT; + u64 to = from + size; + u64 cursor = from; + + while (cursor < to) { + if (!devmem_is_allowed(pfn)) { + printk(KERN_INFO + "Program %s tried to access /dev/mem between %Lx->%Lx.\n", current->comm, from, to); return 0; } - cursor++; + cursor += PAGE_SIZE; + pfn++; } return 1; } #else -static inline int range_is_allowed(unsigned long from, unsigned long to) +static inline int range_is_allowed(unsigned long pfn, unsigned long size) { return 1; } @@ -181,7 +183,7 @@ */ ptr = xlate_dev_mem_ptr(p); - if (!range_is_allowed(p, p+count)) + if (!range_is_allowed(p >> PAGE_SHIFT, count)) return -EPERM; if (copy_to_user(buf, ptr, sz)) return -EFAULT; @@ -240,7 +242,7 @@ */ ptr = xlate_dev_mem_ptr(p); - if (!range_is_allowed(p, p+sz)) + if (!range_is_allowed(p >> PAGE_SHIFT, sz)) return -EPERM; copied = copy_from_user(ptr, buf, sz); if (copied) { @@ -309,6 +311,9 @@ if (!private_mapping_ok(vma)) return -ENOSYS; + if (!range_is_allowed(vma->vm_pgoff, size)) + return -EPERM; + vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, size, vma->vm_page_prot);
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