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Merge branch 'gadget' of git://git.kernel.org/pub/scm/linux/kernel/gi…
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…t/viro/vfs

Pull gadgetfs fixes from Al Viro:
 "Assorted fixes around AIO on gadgetfs: leaks, use-after-free, troubles
  caused by ->f_op flipping"

* 'gadget' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  gadgetfs: really get rid of switching ->f_op
  gadgetfs: get rid of flipping ->f_op in ep_config()
  gadget: switch ep_io_operations to ->read_iter/->write_iter
  gadgetfs: use-after-free in ->aio_read()
  gadget/function/f_fs.c: switch to ->{read,write}_iter()
  gadget/function/f_fs.c: use put iov_iter into io_data
  gadget/function/f_fs.c: close leaks
  move iov_iter.c from mm/ to lib/
  new helper: dup_iter()
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@torvalds
torvalds committed Mar 13, 2015
2 parents c202baf + 96b62a5 commit f788baa
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Showing 6 changed files with 291 additions and 400 deletions.
204 changes: 79 additions & 125 deletions drivers/usb/gadget/function/f_fs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -144,10 +144,9 @@ struct ffs_io_data {
bool read;

struct kiocb *kiocb;
const struct iovec *iovec;
unsigned long nr_segs;
char __user *buf;
size_t len;
struct iov_iter data;
const void *to_free;
char *buf;

struct mm_struct *mm;
struct work_struct work;
Expand Down Expand Up @@ -649,29 +648,10 @@ static void ffs_user_copy_worker(struct work_struct *work)
io_data->req->actual;

if (io_data->read && ret > 0) {
int i;
size_t pos = 0;

/*
* Since req->length may be bigger than io_data->len (after
* being rounded up to maxpacketsize), we may end up with more
* data then user space has space for.
*/
ret = min_t(int, ret, io_data->len);

use_mm(io_data->mm);
for (i = 0; i < io_data->nr_segs; i++) {
size_t len = min_t(size_t, ret - pos,
io_data->iovec[i].iov_len);
if (!len)
break;
if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
&io_data->buf[pos], len))) {
ret = -EFAULT;
break;
}
pos += len;
}
ret = copy_to_iter(io_data->buf, ret, &io_data->data);
if (iov_iter_count(&io_data->data))
ret = -EFAULT;
unuse_mm(io_data->mm);
}

Expand All @@ -684,7 +664,7 @@ static void ffs_user_copy_worker(struct work_struct *work)

io_data->kiocb->private = NULL;
if (io_data->read)
kfree(io_data->iovec);
kfree(io_data->to_free);
kfree(io_data->buf);
kfree(io_data);
}
Expand Down Expand Up @@ -743,41 +723,29 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
* before the waiting completes, so do not assign to 'gadget' earlier
*/
struct usb_gadget *gadget = epfile->ffs->gadget;
size_t copied;

spin_lock_irq(&epfile->ffs->eps_lock);
/* In the meantime, endpoint got disabled or changed. */
if (epfile->ep != ep) {
spin_unlock_irq(&epfile->ffs->eps_lock);
return -ESHUTDOWN;
}
data_len = iov_iter_count(&io_data->data);
/*
* Controller may require buffer size to be aligned to
* maxpacketsize of an out endpoint.
*/
data_len = io_data->read ?
usb_ep_align_maybe(gadget, ep->ep, io_data->len) :
io_data->len;
if (io_data->read)
data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
spin_unlock_irq(&epfile->ffs->eps_lock);

data = kmalloc(data_len, GFP_KERNEL);
if (unlikely(!data))
return -ENOMEM;
if (io_data->aio && !io_data->read) {
int i;
size_t pos = 0;
for (i = 0; i < io_data->nr_segs; i++) {
if (unlikely(copy_from_user(&data[pos],
io_data->iovec[i].iov_base,
io_data->iovec[i].iov_len))) {
ret = -EFAULT;
goto error;
}
pos += io_data->iovec[i].iov_len;
}
} else {
if (!io_data->read &&
unlikely(__copy_from_user(data, io_data->buf,
io_data->len))) {
if (!io_data->read) {
copied = copy_from_iter(data, data_len, &io_data->data);
if (copied != data_len) {
ret = -EFAULT;
goto error;
}
Expand Down Expand Up @@ -876,10 +844,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
*/
ret = ep->status;
if (io_data->read && ret > 0) {
ret = min_t(size_t, ret, io_data->len);

if (unlikely(copy_to_user(io_data->buf,
data, ret)))
ret = copy_to_iter(data, ret, &io_data->data);
if (unlikely(iov_iter_count(&io_data->data)))
ret = -EFAULT;
}
}
Expand All @@ -898,37 +864,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
return ret;
}

static ssize_t
ffs_epfile_write(struct file *file, const char __user *buf, size_t len,
loff_t *ptr)
{
struct ffs_io_data io_data;

ENTER();

io_data.aio = false;
io_data.read = false;
io_data.buf = (char * __user)buf;
io_data.len = len;

return ffs_epfile_io(file, &io_data);
}

static ssize_t
ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr)
{
struct ffs_io_data io_data;

ENTER();

io_data.aio = false;
io_data.read = true;
io_data.buf = buf;
io_data.len = len;

return ffs_epfile_io(file, &io_data);
}

static int
ffs_epfile_open(struct inode *inode, struct file *file)
{
Expand Down Expand Up @@ -965,67 +900,86 @@ static int ffs_aio_cancel(struct kiocb *kiocb)
return value;
}

static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
const struct iovec *iovec,
unsigned long nr_segs, loff_t loff)
static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
{
struct ffs_io_data *io_data;
struct ffs_io_data io_data, *p = &io_data;
ssize_t res;

ENTER();

io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
if (unlikely(!io_data))
return -ENOMEM;
if (!is_sync_kiocb(kiocb)) {
p = kmalloc(sizeof(io_data), GFP_KERNEL);
if (unlikely(!p))
return -ENOMEM;
p->aio = true;
} else {
p->aio = false;
}

io_data->aio = true;
io_data->read = false;
io_data->kiocb = kiocb;
io_data->iovec = iovec;
io_data->nr_segs = nr_segs;
io_data->len = kiocb->ki_nbytes;
io_data->mm = current->mm;
p->read = false;
p->kiocb = kiocb;
p->data = *from;
p->mm = current->mm;

kiocb->private = io_data;
kiocb->private = p;

kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);

return ffs_epfile_io(kiocb->ki_filp, io_data);
res = ffs_epfile_io(kiocb->ki_filp, p);
if (res == -EIOCBQUEUED)
return res;
if (p->aio)
kfree(p);
else
*from = p->data;
return res;
}

static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
const struct iovec *iovec,
unsigned long nr_segs, loff_t loff)
static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
{
struct ffs_io_data *io_data;
struct iovec *iovec_copy;
struct ffs_io_data io_data, *p = &io_data;
ssize_t res;

ENTER();

iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL);
if (unlikely(!iovec_copy))
return -ENOMEM;

memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs);

io_data = kmalloc(sizeof(*io_data), GFP_KERNEL);
if (unlikely(!io_data)) {
kfree(iovec_copy);
return -ENOMEM;
if (!is_sync_kiocb(kiocb)) {
p = kmalloc(sizeof(io_data), GFP_KERNEL);
if (unlikely(!p))
return -ENOMEM;
p->aio = true;
} else {
p->aio = false;
}

io_data->aio = true;
io_data->read = true;
io_data->kiocb = kiocb;
io_data->iovec = iovec_copy;
io_data->nr_segs = nr_segs;
io_data->len = kiocb->ki_nbytes;
io_data->mm = current->mm;
p->read = true;
p->kiocb = kiocb;
if (p->aio) {
p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
if (!p->to_free) {
kfree(p);
return -ENOMEM;
}
} else {
p->data = *to;
p->to_free = NULL;
}
p->mm = current->mm;

kiocb->private = io_data;
kiocb->private = p;

kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);

return ffs_epfile_io(kiocb->ki_filp, io_data);
res = ffs_epfile_io(kiocb->ki_filp, p);
if (res == -EIOCBQUEUED)
return res;

if (p->aio) {
kfree(p->to_free);
kfree(p);
} else {
*to = p->data;
}
return res;
}

static int
Expand Down Expand Up @@ -1105,10 +1059,10 @@ static const struct file_operations ffs_epfile_operations = {
.llseek = no_llseek,

.open = ffs_epfile_open,
.write = ffs_epfile_write,
.read = ffs_epfile_read,
.aio_write = ffs_epfile_aio_write,
.aio_read = ffs_epfile_aio_read,
.write = new_sync_write,
.read = new_sync_read,
.write_iter = ffs_epfile_write_iter,
.read_iter = ffs_epfile_read_iter,
.release = ffs_epfile_release,
.unlocked_ioctl = ffs_epfile_ioctl,
};
Expand Down
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