linux-kernel - [PATCH 4.12 36/65] staging: comedi: comedi_fops: do not call blocking ops when !TASK

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: <20170815011943.821579668@linuxfoundation.org>
Date:   Mon, 14 Aug 2017 18:19:27 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Piotr Gregor <piotrgregor@...ncme.org>,
        Ian Abbott <abbotti@....co.uk>
Subject: [PATCH 4.12 36/65] staging: comedi: comedi_fops: do not call blocking ops when !TASK_RUNNING

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

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

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

commit cef988642cdac44e910a27cb6e8166c96f86a0df upstream.

Comedi's read and write file operation handlers (`comedi_read()` and
`comedi_write()`) currently call `copy_to_user()` or `copy_from_user()`
whilst in the `TASK_INTERRUPTIBLE` state, which falls foul of the
`might_fault()` checks when enabled.  Fix it by setting the current task
state back to `TASK_RUNNING` a bit earlier before calling these
functions.

Reported-by: Piotr Gregor <piotrgregor@...ncme.org>
Signed-off-by: Ian Abbott <abbotti@....co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/staging/comedi/comedi_fops.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2396,6 +2396,7 @@ static ssize_t comedi_write(struct file
 			continue;
 		}
 
+		set_current_state(TASK_RUNNING);
 		wp = async->buf_write_ptr;
 		n1 = min(n, async->prealloc_bufsz - wp);
 		n2 = n - n1;
@@ -2528,6 +2529,8 @@ static ssize_t comedi_read(struct file *
 			}
 			continue;
 		}
+
+		set_current_state(TASK_RUNNING);
 		rp = async->buf_read_ptr;
 		n1 = min(n, async->prealloc_bufsz - rp);
 		n2 = n - n1;