linux-kernel - [PATCH 3.12 163/175] staging: comedi: comedi_compat32.c: fix COMEDI

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <b848046a02bc2a35da3f6a0fbae8db6ff1691cc4.1426581621.git.jslaby@suse.cz>
Date:	Tue, 17 Mar 2015 09:42:21 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Ian Abbott <abbotti@....co.uk>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 163/175] staging: comedi: comedi_compat32.c: fix COMEDI_CMD copy back

From: Ian Abbott <abbotti@....co.uk>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 42b8ce6f55facfa101462e694d33fc6bca471138 upstream.

`do_cmd_ioctl()` in "comedi_fops.c" handles the `COMEDI_CMD` ioctl.
This returns `-EAGAIN` if it has copied a modified `struct comedi_cmd`
back to user-space.  (This occurs when the low-level Comedi driver's
`do_cmdtest()` handler returns non-zero to indicate a problem with the
contents of the `struct comedi_cmd`, or when the `struct comedi_cmd` has
the `CMDF_BOGUS` flag set.)

`compat_cmd()` in "comedi_compat32.c" handles the 32-bit compatible
version of the `COMEDI_CMD` ioctl.  Currently, it never copies a 32-bit
compatible version of `struct comedi_cmd` back to user-space, which is
at odds with the way the regular `COMEDI_CMD` ioctl is handled.  To fix
it, change `compat_cmd()` to copy a 32-bit compatible version of the
`struct comedi_cmd` back to user-space when the main ioctl handler
returns `-EAGAIN`.

Signed-off-by: Ian Abbott <abbotti@....co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 drivers/staging/comedi/comedi_compat32.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/comedi/comedi_compat32.c b/drivers/staging/comedi/comedi_compat32.c
index 2dfb06aedb15..b1c264e3a7b4 100644
--- a/drivers/staging/comedi/comedi_compat32.c
+++ b/drivers/staging/comedi/comedi_compat32.c
@@ -265,7 +265,7 @@ static int compat_cmd(struct file *file, unsigned long arg)
 {
 	struct comedi_cmd __user *cmd;
 	struct comedi32_cmd_struct __user *cmd32;
-	int rc;
+	int rc, err;

 	cmd32 = compat_ptr(arg);
 	cmd = compat_alloc_user_space(sizeof(*cmd));
@@ -274,7 +274,15 @@ static int compat_cmd(struct file *file, unsigned long arg)
 	if (rc)
 		return rc;

-	return translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
+	rc = translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
+	if (rc == -EAGAIN) {
+		/* Special case: copy cmd back to user. */
+		err = put_compat_cmd(cmd32, cmd);
+		if (err)
+			rc = err;
+	}
+
+	return rc;
 }

 /* Handle 32-bit COMEDI_CMDTEST ioctl. */
-- 
2.3.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/