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devmem: add range_is_allowed() check to mmap of /dev/mem 

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>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Venki Pallipadi 2008-03-06 23:01:47 -08:00 committed by Ingo Molnar
parent ae531c26c5
commit e2beb3eae6
1 changed files with 16 additions and 11 deletions
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27
drivers/char/mem.c
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@ -109,24 +109,26 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
#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;
u64 from = ((u64)pfn) << PAGE_SHIFT;
u64 to = from + size;
u64 cursor = from;
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",
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 @@ static ssize_t read_mem(struct file * file, char __user * buf,
*/
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 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
*/
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 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
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);