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| author | Andrzej Pietrasiewicz <andrzej.p@samsung.com> | 2014-01-20 08:33:50 +0100 |
|---|---|---|
| committer | Felipe Balbi <balbi@ti.com> | 2014-02-20 09:17:23 -0600 |
| commit | f0f42204d0cc04a63ac61fdaa3b6a269ea0dc08b (patch) | |
| tree | 5e564e3f582d872a91433cc62dc1fa3ff8007cbd /drivers/usb/gadget | |
| parent | 8679059e360543b7afecd228ada6566da9f304a4 (diff) | |
| download | linux-f0f42204d0cc04a63ac61fdaa3b6a269ea0dc08b.tar.gz | |
usb: gadget: fix NULL pointer dereference
Fix possible NULL pointer dereference introduced in commit 219580e (usb: f_fs: check quirk to pad epout buf size when not aligned to maxpacketsize) In cases we do wait with: wait_event_interruptible(epfile->wait, (ep = epfile->ep)); for endpoint to be enabled, functionfs_bind() has not been called yet and epfile->ffs->gadget is still NULL and the automatic variable 'gadget' has been initialized with NULL at the point of its definition. Later on it is used as a parameter to: usb_ep_align_maybe(gadget, ep->ep, len) which in turn dereferences it. This patch fixes it by moving the actual assignment to the local 'gadget' variable after the potential waiting has completed. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Felipe Balbi <balbi@ti.com>
Diffstat (limited to 'drivers/usb/gadget')
| -rw-r--r-- | drivers/usb/gadget/f_fs.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c index 306a2b52125c..2b4334394076 100644 --- a/drivers/usb/gadget/f_fs.c +++ b/drivers/usb/gadget/f_fs.c @@ -585,7 +585,6 @@ static ssize_t ffs_epfile_io(struct file *file, char __user *buf, size_t len, int read) { struct ffs_epfile *epfile = file->private_data; - struct usb_gadget *gadget = epfile->ffs->gadget; struct ffs_ep *ep; char *data = NULL; ssize_t ret, data_len; @@ -622,6 +621,12 @@ static ssize_t ffs_epfile_io(struct file *file, /* Allocate & copy */ if (!halt) { /* + * if we _do_ wait above, the epfile->ffs->gadget might be NULL + * before the waiting completes, so do not assign to 'gadget' earlier + */ + struct usb_gadget *gadget = epfile->ffs->gadget; + + /* * Controller may require buffer size to be aligned to * maxpacketsize of an out endpoint. */ |