Fix two possible issue in ffs_epfile_io() when operation at blocking mode.
v1: https://lore.kernel.org/linux-usb/1653989775-14267-1-git-send-email-quic_lin... v2: correct interrupted variable according comment from John Keeping v3: (v2: https://lore.kernel.org/linux-usb/1654006119-23869-1-git-send-email-quic_lin...) add Revived-by from John keeping, after offline discussion, add Reported-by from Michael Wu v4: (v3: https://lore.kernel.org/linux-usb/1654056916-2062-1-git-send-email-quic_liny...) add Cc: stable@vger.kernel.org # 5.15 (seem other branch can't aplly cleanly), add Tested-by: Michael Wu michael@allwinnertech.com, remove one empty line to keep original code format.
Linyu Yuan (2): usb: gadget: f_fs: change ep->status safe in ffs_epfile_io() usb: gadget: f_fs: change ep->ep safe in ffs_epfile_io()
drivers/usb/gadget/function/f_fs.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-)
If a task read/write data in blocking mode, it will wait the completion in ffs_epfile_io(), if function unbind occurs, ffs_func_unbind() will kfree ffs ep, once the task wake up, it still dereference the ffs ep to obtain the request status.
Fix it by moving the request status to io_data which is stack-safe.
Cc: stable@vger.kernel.org # 5.15 Reported-by: Michael Wu michael@allwinnertech.com Tested-by: Michael Wu michael@allwinnertech.com Reviewed-by: John Keeping john@metanate.com Signed-off-by: Linyu Yuan quic_linyyuan@quicinc.com --- v2: correct interrupted assignment v3: add Reviewed-by and Reported-by v4: add Tetsed-by from Michael Wu, remove one empty line cc stable kernel
drivers/usb/gadget/function/f_fs.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 4585ee3..3958c60 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -122,8 +122,6 @@ struct ffs_ep { struct usb_endpoint_descriptor *descs[3];
u8 num; - - int status; /* P: epfile->mutex */ };
struct ffs_epfile { @@ -227,6 +225,9 @@ struct ffs_io_data { bool use_sg;
struct ffs_data *ffs; + + int status; + struct completion done; };
struct ffs_desc_helper { @@ -707,12 +708,12 @@ static const struct file_operations ffs_ep0_operations = {
static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req) { + struct ffs_io_data *io_data = req->context; + ENTER(); - if (req->context) { - struct ffs_ep *ep = _ep->driver_data; - ep->status = req->status ? req->status : req->actual; - complete(req->context); - } + + io_data->status = req->status ? req->status : req->actual; + complete(&io_data->done); }
static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter) @@ -1050,7 +1051,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) WARN(1, "%s: data_len == -EINVAL\n", __func__); ret = -EINVAL; } else if (!io_data->aio) { - DECLARE_COMPLETION_ONSTACK(done); bool interrupted = false;
req = ep->req; @@ -1066,7 +1066,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
io_data->buf = data;
- req->context = &done; + init_completion(&io_data->done); + req->context = io_data; req->complete = ffs_epfile_io_complete;
ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC); @@ -1075,7 +1076,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
spin_unlock_irq(&epfile->ffs->eps_lock);
- if (wait_for_completion_interruptible(&done)) { + if (wait_for_completion_interruptible(&io_data->done)) { /* * To avoid race condition with ffs_epfile_io_complete, * dequeue the request first then check @@ -1083,17 +1084,17 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) * condition with req->complete callback. */ usb_ep_dequeue(ep->ep, req); - wait_for_completion(&done); - interrupted = ep->status < 0; + wait_for_completion(&io_data->done); + interrupted = io_data->status < 0; }
if (interrupted) ret = -EINTR; - else if (io_data->read && ep->status > 0) - ret = __ffs_epfile_read_data(epfile, data, ep->status, + else if (io_data->read && io_data->status > 0) + ret = __ffs_epfile_read_data(epfile, data, io_data->status, &io_data->data); else - ret = ep->status; + ret = io_data->status; goto error_mutex; } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) { ret = -ENOMEM;
On Sat, Jun 04, 2022 at 10:54:54AM +0800, Linyu Yuan wrote:
If a task read/write data in blocking mode, it will wait the completion in ffs_epfile_io(), if function unbind occurs, ffs_func_unbind() will kfree ffs ep, once the task wake up, it still dereference the ffs ep to obtain the request status.
Fix it by moving the request status to io_data which is stack-safe.
Cc: stable@vger.kernel.org # 5.15 Reported-by: Michael Wu michael@allwinnertech.com Tested-by: Michael Wu michael@allwinnertech.com Reviewed-by: John Keeping john@metanate.com Signed-off-by: Linyu Yuan quic_linyyuan@quicinc.com
v2: correct interrupted assignment v3: add Reviewed-by and Reported-by v4: add Tetsed-by from Michael Wu, remove one empty line cc stable kernel
drivers/usb/gadget/function/f_fs.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 4585ee3..3958c60 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -122,8 +122,6 @@ struct ffs_ep { struct usb_endpoint_descriptor *descs[3]; u8 num;
- int status; /* P: epfile->mutex */
}; struct ffs_epfile { @@ -227,6 +225,9 @@ struct ffs_io_data { bool use_sg; struct ffs_data *ffs;
- int status;
- struct completion done;
}; struct ffs_desc_helper { @@ -707,12 +708,12 @@ static const struct file_operations ffs_ep0_operations = { static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req) {
- struct ffs_io_data *io_data = req->context;
- ENTER();
- if (req->context) {
struct ffs_ep *ep = _ep->driver_data;
ep->status = req->status ? req->status : req->actual;
complete(req->context);
- }
- io_data->status = req->status ? req->status : req->actual;
Please do not use ? : lines unless you have to. Please write this as normal if () lines.
thanks,
greg k-h
In ffs_epfile_io(), when read/write data in blocking mode, it will wait the completion in interruptible mode, if task receive a signal, it will terminate the wait, at same time, if function unbind occurs, ffs_func_unbind() will kfree all eps, ffs_epfile_io() still try to dequeue request by dereferencing ep which may become invalid.
Fix it by add ep spinlock and will not dereference ep if it is not valid.
Cc: stable@vger.kernel.org # 5.15 Reported-by: Michael Wu michael@allwinnertech.com Tested-by: Michael Wu michael@allwinnertech.com Reviewed-by: John Keeping john@metanate.com Signed-off-by: Linyu Yuan quic_linyyuan@quicinc.com --- v2: add Reviewed-by from John keeping v3: add Reported-by from Michael Wu v4: add Tested-by from Michael Wu cc stable kernel
drivers/usb/gadget/function/f_fs.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 3958c60..b0c046a 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1077,6 +1077,11 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) spin_unlock_irq(&epfile->ffs->eps_lock);
if (wait_for_completion_interruptible(&io_data->done)) { + spin_lock_irq(&epfile->ffs->eps_lock); + if (epfile->ep != ep) { + ret = -ESHUTDOWN; + goto error_lock; + } /* * To avoid race condition with ffs_epfile_io_complete, * dequeue the request first then check @@ -1084,6 +1089,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) * condition with req->complete callback. */ usb_ep_dequeue(ep->ep, req); + spin_unlock_irq(&epfile->ffs->eps_lock); wait_for_completion(&io_data->done); interrupted = io_data->status < 0; }
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