From 182d679b2298d62bf42bb14b12a8067b8e17b617 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 17 Feb 2021 12:21:10 -0800 Subject: [PATCH] Input: joydev - prevent potential read overflow in ioctl The problem here is that "len" might be less than "joydev->nabs" so the loops which verfy abspam[i] and keypam[] might read beyond the buffer. Fixes: 999b874f4aa3 ("Input: joydev - validate axis/button maps before clobbering current ones") Signed-off-by: Dan Carpenter Link: https://lore.kernel.org/r/YCyzR8WvFRw4HWw6@mwanda [dtor: additional check for len being even in joydev_handle_JSIOCSBTNMAP] Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov --- drivers/input/joydev.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/input/joydev.c b/drivers/input/joydev.c index a2b5fbba2d3b..430dc6975004 100644 --- a/drivers/input/joydev.c +++ b/drivers/input/joydev.c @@ -456,7 +456,7 @@ static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev, if (IS_ERR(abspam)) return PTR_ERR(abspam); - for (i = 0; i < joydev->nabs; i++) { + for (i = 0; i < len && i < joydev->nabs; i++) { if (abspam[i] > ABS_MAX) { retval = -EINVAL; goto out; @@ -480,6 +480,9 @@ static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev, int i; int retval = 0; + if (len % sizeof(*keypam)) + return -EINVAL; + len = min(len, sizeof(joydev->keypam)); /* Validate the map. */ @@ -487,7 +490,7 @@ static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev, if (IS_ERR(keypam)) return PTR_ERR(keypam); - for (i = 0; i < joydev->nkey; i++) { + for (i = 0; i < (len / 2) && i < joydev->nkey; i++) { if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) { retval = -EINVAL; goto out;