This is a note to let you know that I've just added the patch titled
staging: comedi: comedi_compat32.c: fix COMEDI_CMD copy back
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-next 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 also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From 42b8ce6f55facfa101462e694d33fc6bca471138 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@xxxxxxxxx>
Date: Tue, 27 Jan 2015 18:16:51 +0000
Subject: staging: comedi: comedi_compat32.c: fix COMEDI_CMD copy back
`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@xxxxxxxxx>
Reviewed-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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 5a4c74f703b3..03a2d0784419 100644
--- a/drivers/staging/comedi/comedi_compat32.c
+++ b/drivers/staging/comedi/comedi_compat32.c
@@ -262,7 +262,7 @@ 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));
@@ -271,7 +271,15 @@ 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. */
--
2.2.2
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