diff options
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 20070b7c573..dcf6e31970a 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -108,6 +108,30 @@ 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) +{ + 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", + current->comm, from, to); + return 0; + } + cursor++; + } + return 1; +} +#else +static inline int range_is_allowed(unsigned long from, unsigned long to) +{ + return 1; +} +#endif + /* * This funcion reads the *physical* memory. The f_pos points directly to the * memory location. @@ -157,6 +181,8 @@ static ssize_t read_mem(struct file * file, char __user * buf, */ ptr = xlate_dev_mem_ptr(p); + if (!range_is_allowed(p, p+count)) + return -EPERM; if (copy_to_user(buf, ptr, sz)) return -EFAULT; buf += sz; @@ -214,6 +240,8 @@ 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)) + return -EPERM; copied = copy_from_user(ptr, buf, sz); if (copied) { written += sz - copied; |