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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Mayank Rana <mrana@codeaurora.org>,
        Jack Pham <jackp@codeaurora.org>,
        Felipe Balbi <felipe.balbi@linux.intel.com>
Subject: [PATCH 4.9 21/39] usb: gadget: f_fs: Process all descriptors during bind
Date:   Mon, 26 Feb 2018 21:20:42 +0100
Message-Id: <20180226201644.602974011@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jack Pham <jackp@codeaurora.org>

commit 6cf439e0d37463e42784271179c8a308fd7493c6 upstream.

During _ffs_func_bind(), the received descriptors are evaluated
to prepare for binding with the gadget in order to allocate
endpoints and optionally set up OS descriptors. However, the
high- and super-speed descriptors are only parsed based on
whether the gadget_is_dualspeed() and gadget_is_superspeed()
calls are true, respectively.

This is a problem in case a userspace program always provides
all of the {full,high,super,OS} descriptors when configuring a
function. Then, for example if a gadget device is not capable
of SuperSpeed, the call to ffs_do_descs() for the SS descriptors
is skipped, resulting in an incorrect offset calculation for
the vla_ptr when moving on to the OS descriptors that follow.
This causes ffs_do_os_descs() to fail as it is now looking at
the SS descriptors' offset within the raw_descs buffer instead.

_ffs_func_bind() should evaluate the descriptors unconditionally,
so remove the checks for gadget speed.

Fixes: f0175ab51993 ("usb: gadget: f_fs: OS descriptors support")
Cc: stable@vger.kernel.org
Co-Developed-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/function/f_fs.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -2956,10 +2956,8 @@ static int _ffs_func_bind(struct usb_con
 	struct ffs_data *ffs = func->ffs;
 
 	const int full = !!func->ffs->fs_descs_count;
-	const int high = gadget_is_dualspeed(func->gadget) &&
-		func->ffs->hs_descs_count;
-	const int super = gadget_is_superspeed(func->gadget) &&
-		func->ffs->ss_descs_count;
+	const int high = !!func->ffs->hs_descs_count;
+	const int super = !!func->ffs->ss_descs_count;
 
 	int fs_len, hs_len, ss_len, ret, i;
 	struct ffs_ep *eps_ptr;