mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 01:41:39 +00:00
devmem: check vmalloc address on kmem read/write
Otherwise vmalloc_to_page() will BUG(). This also makes the kmem read/write implementation aligned with mem(4): "References to nonexistent locations cause errors to be returned." Here we return -ENXIO (inspired by Hugh) if no bytes have been transfered to/from user space, otherwise return partial read/write results. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
931e80e4b3
commit
325fda71d0
1 changed files with 18 additions and 10 deletions
|
@ -395,6 +395,7 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
|
|||
unsigned long p = *ppos;
|
||||
ssize_t low_count, read, sz;
|
||||
char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
|
||||
int err = 0;
|
||||
|
||||
read = 0;
|
||||
if (p < (unsigned long) high_memory) {
|
||||
|
@ -441,12 +442,16 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
|
|||
return -ENOMEM;
|
||||
while (count > 0) {
|
||||
sz = size_inside_page(p, count);
|
||||
if (!is_vmalloc_or_module_addr((void *)p)) {
|
||||
err = -ENXIO;
|
||||
break;
|
||||
}
|
||||
sz = vread(kbuf, (char *)p, sz);
|
||||
if (!sz)
|
||||
break;
|
||||
if (copy_to_user(buf, kbuf, sz)) {
|
||||
free_page((unsigned long)kbuf);
|
||||
return -EFAULT;
|
||||
err = -EFAULT;
|
||||
break;
|
||||
}
|
||||
count -= sz;
|
||||
buf += sz;
|
||||
|
@ -455,8 +460,8 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
|
|||
}
|
||||
free_page((unsigned long)kbuf);
|
||||
}
|
||||
*ppos = p;
|
||||
return read;
|
||||
*ppos = p;
|
||||
return read ? read : err;
|
||||
}
|
||||
|
||||
|
||||
|
@ -520,6 +525,7 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
|
|||
ssize_t wrote = 0;
|
||||
ssize_t virtr = 0;
|
||||
char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
|
||||
int err = 0;
|
||||
|
||||
if (p < (unsigned long) high_memory) {
|
||||
unsigned long to_write = min_t(unsigned long, count,
|
||||
|
@ -540,12 +546,14 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
|
|||
unsigned long sz = size_inside_page(p, count);
|
||||
unsigned long n;
|
||||
|
||||
if (!is_vmalloc_or_module_addr((void *)p)) {
|
||||
err = -ENXIO;
|
||||
break;
|
||||
}
|
||||
n = copy_from_user(kbuf, buf, sz);
|
||||
if (n) {
|
||||
if (wrote + virtr)
|
||||
break;
|
||||
free_page((unsigned long)kbuf);
|
||||
return -EFAULT;
|
||||
err = -EFAULT;
|
||||
break;
|
||||
}
|
||||
sz = vwrite(kbuf, (char *)p, sz);
|
||||
count -= sz;
|
||||
|
@ -556,8 +564,8 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
|
|||
free_page((unsigned long)kbuf);
|
||||
}
|
||||
|
||||
*ppos = p;
|
||||
return virtr + wrote;
|
||||
*ppos = p;
|
||||
return virtr + wrote ? : err;
|
||||
}
|
||||
#endif
|
||||
|
||||
|
|
Loading…
Reference in a new issue