diff options
| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2010-02-05 15:01:09 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-02-23 07:37:54 -0800 |
| commit | 6b344d83ca458327faa0e1f6afd45c39cceab2a6 (patch) | |
| tree | d3fae8ec89634c8a079a456e0c9cfd29373ed617 /drivers | |
| parent | 0e1104ada32d242bc6169a2ce4eb19ec4febb813 (diff) | |
devmem: check vmalloc address on kmem read/write
commit 325fda71d0badc1073dc59f12a948f24ff05796a
[ cebbert@redhat.com : backport to 2.6.32 ]
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/char/mem.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 1ffb6dd3eae4..96b2586d2bec 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -421,6 +421,7 @@ 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) { @@ -469,12 +470,16 @@ static ssize_t read_kmem(struct file *file, char __user *buf, while (count > 0) { int len = size_inside_page(p, count); + if (!is_vmalloc_or_module_addr((void *)p)) { + err = -ENXIO; + break; + } len = vread(kbuf, (char *)p, len); if (!len) break; if (copy_to_user(buf, kbuf, len)) { - free_page((unsigned long)kbuf); - return -EFAULT; + err = -EFAULT; + break; } count -= len; buf += len; @@ -483,8 +488,8 @@ 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; } @@ -553,6 +558,7 @@ static ssize_t write_kmem(struct file * file, const char __user * buf, ssize_t virtr = 0; ssize_t written; char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ + int err = 0; if (p < (unsigned long) high_memory) { @@ -576,13 +582,15 @@ static ssize_t write_kmem(struct file * file, const char __user * buf, while (count > 0) { int len = size_inside_page(p, count); + if (!is_vmalloc_or_module_addr((void *)p)) { + err = -ENXIO; + break; + } if (len) { written = copy_from_user(kbuf, buf, len); if (written) { - if (wrote + virtr) - break; - free_page((unsigned long)kbuf); - return -EFAULT; + err = -EFAULT; + break; } } len = vwrite(kbuf, (char *)p, len); @@ -594,8 +602,8 @@ 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 |