This is a note to let you know that I've just added the patch titled
usb: gadget: f_fs: data_len used before properly set
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the usb-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 4833a94eb383f5b22775077ff92ddaae90440921 Mon Sep 17 00:00:00 2001
From: Fei Yang <fei.yang@xxxxxxxxx>
Date: Wed, 12 Jun 2019 15:13:26 -0700
Subject: usb: gadget: f_fs: data_len used before properly set
The following line of code in function ffs_epfile_io is trying to set
flag io_data->use_sg in case buffer required is larger than one page.
io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
However at this point of time the variable data_len has not been set
to the proper buffer size yet. The consequence is that io_data->use_sg
is always set regardless what buffer size really is, because the condition
(data_len > PAGE_SIZE) is effectively an unsigned comparison between
-EINVAL and PAGE_SIZE which would always result in TRUE.
Fixes: 772a7a724f69 ("usb: gadget: f_fs: Allow scatter-gather buffers")
Signed-off-by: Fei Yang <fei.yang@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_fs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 47be961f1bf3..c7ed90084d1a 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -997,7 +997,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
* earlier
*/
gadget = epfile->ffs->gadget;
- io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
spin_lock_irq(&epfile->ffs->eps_lock);
/* In the meantime, endpoint got disabled or changed. */
@@ -1012,6 +1011,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
*/
if (io_data->read)
data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
+
+ io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
spin_unlock_irq(&epfile->ffs->eps_lock);
data = ffs_alloc_buffer(io_data, data_len);
--
2.22.0
