linux-kernel - [PATCH] tty/vt: set_get

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 for Android: free password hash cracker in your pocket

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

Message-Id: <1332200041-31052-1-git-send-email-mg@ebfe.org>
Date:	Tue, 20 Mar 2012 00:34:01 +0100
From:	Michael Gehring <mg@...e.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	linux-kernel@...r.kernel.org, Michael Gehring <mg@...e.org>
Subject: [PATCH] tty/vt: set_get_cmap() check user buffer

set_get_cmap() ignores the result of {get,put}_user(), causing ioctl(vt,
{G,P}IO_CMAP, 0xdeadbeef) to silently fail.

Another side effect of this: calling the PIO_CMAP ioctl with an invalid
buffer will zero the default colormap and the palette for all vts (all
colors set to black).

Use access_ok() and return -EFAULT when appropriate.

Signed-off-by: Michael Gehring <mg@...e.org>
---
 drivers/tty/vt/vt.c |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index e716839..176b2a1 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3897,15 +3897,18 @@ static int set_get_cmap(unsigned char __user *arg, int set)
 
     WARN_CONSOLE_UNLOCKED();
 
+    if (!access_ok(set ? VERIFY_READ : VERIFY_WRITE, arg, 3 * 16))
+	return -EFAULT;
+
     for (i = 0; i < 16; i++)
 	if (set) {
-	    get_user(default_red[i], arg++);
-	    get_user(default_grn[i], arg++);
-	    get_user(default_blu[i], arg++);
+	    __get_user(default_red[i], arg++);
+	    __get_user(default_grn[i], arg++);
+	    __get_user(default_blu[i], arg++);
 	} else {
-	    put_user(default_red[i], arg++);
-	    put_user(default_grn[i], arg++);
-	    put_user(default_blu[i], arg++);
+	    __put_user(default_red[i], arg++);
+	    __put_user(default_grn[i], arg++);
+	    __put_user(default_blu[i], arg++);
 	}
     if (set) {
 	for (i = 0; i < MAX_NR_CONSOLES; i++)
-- 
1.7.9.4

--
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/