[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20211108185818.GA73382@makvihas>
Date: Tue, 9 Nov 2021 00:28:18 +0530
From: Vihas Mak <makvihas@...il.com>
To: sudipm.mukherjee@...il.com
Cc: arnd@...db.de, gregkh@...uxfoundation.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] char: ppdev: fixed a validation issue
Make sure the mode is a valid IEEE1284 mode.
Signed-off-by: Vihas Mak <makvihas@...il.com>
---
drivers/char/ppdev.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index 38b46c7d1737..3b290cbf6c66 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -333,6 +333,28 @@ static enum ieee1284_phase init_phase(int mode)
return IEEE1284_PH_FWD_IDLE;
}
+/*
+ * Validate the mode and make sure the mode is power of two.
+ *
+ * IEEE1284_MODE_ECPRLE and IEEE1284_MODE_NIBBLE are exception
+ * to this so handle them accordingly.
+ */
+
+static int pp_validate_mode(int mode)
+{
+ if (mode == IEEE1284_MODE_ECPRLE || mode == IEEE1284_MODE_NIBBLE) {
+ return 1;
+ } else if (!(mode & (mode - 1)) &&
+ (mode & (IEEE1284_MODE_BYTE | IEEE1284_MODE_COMPAT |
+ IEEE1284_MODE_BECP | IEEE1284_MODE_ECP |
+ IEEE1284_MODE_ECPSWE | IEEE1284_MODE_EPP |
+ IEEE1284_MODE_EPPSL | IEEE1284_MODE_COMPAT |
+ IEEE1284_MODE_EPPSWE))) {
+ return 1;
+ }
+ return 0;
+}
+
static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
{
long to_jiffies;
@@ -423,7 +445,11 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (copy_from_user(&mode, argp, sizeof(mode)))
return -EFAULT;
- /* FIXME: validate mode */
+
+ /* Validate mode */
+ if (!pp_validate_mode(mode))
+ return -EINVAL;
+
pp->state.mode = mode;
pp->state.phase = init_phase(mode);
--
2.25.1
Powered by blists - more mailing lists