diff options
Diffstat (limited to 'drivers/char/mem.c')
| -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 |