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Input: joydev - prevent potential read overflow in ioctl

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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: 999b874f4a ("Input: joydev - validate axis/button maps before clobbering current ones")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
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 <dmitry.torokhov@gmail.com>
This commit is contained in:
Dan Carpenter 2021-02-17 12:21:10 -08:00 committed by Dmitry Torokhov
parent 0958351e93
commit 182d679b22
1 changed files with 5 additions and 2 deletions
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7
drivers/input/joydev.c
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@ -456,7 +456,7 @@ static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
if (IS_ERR(abspam)) if (IS_ERR(abspam))
return PTR_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) { if (abspam[i] > ABS_MAX) {
retval = -EINVAL; retval = -EINVAL;
goto out; goto out;
@ -480,6 +480,9 @@ static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
int i; int i;
int retval = 0; int retval = 0;
if (len % sizeof(*keypam))
return -EINVAL;
len = min(len, sizeof(joydev->keypam)); len = min(len, sizeof(joydev->keypam));
/* Validate the map. */ /* Validate the map. */
@ -487,7 +490,7 @@ static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
if (IS_ERR(keypam)) if (IS_ERR(keypam))
return PTR_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) { if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) {
retval = -EINVAL; retval = -EINVAL;
goto out; goto out;