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auxdisplay: ht16k33: don't access uninitialized data

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gcc-7.0.1 points out that we copy uninitialized data from the stack
into a per-device structure:

drivers/auxdisplay/ht16k33.c: In function 'ht16k33_keypad_irq_thread':
arch/x86/include/asm/string_32.h:78:16: error: 'new_state' may be used uninitialized in this function [-Werror=maybe-uninitialized]
arch/x86/include/asm/string_32.h:79:22: error: '*((void *)&new_state+4)' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The access is harmless because we never read the data, but we are better
off not doing this, so this changes the code to only copy the data
that was actually initialized. To make sure we don't overflow the
stack with an incorrect DT, we also need to add a sanity checkin the
probe function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Arnd Bergmann 2017-03-28 12:11:49 +02:00 committed by Greg Kroah-Hartman
parent c7c3f096eb
commit e1f990c24d
1 changed files with 7 additions and 1 deletions
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8
drivers/auxdisplay/ht16k33.c
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@ -278,7 +278,7 @@ static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad)
}
}
input_sync(keypad->dev);
memcpy(keypad->last_key_state, new_state, sizeof(new_state));
memcpy(keypad->last_key_state, new_state, sizeof(u16) * keypad->cols);
return pressed;
}
@ -353,6 +353,12 @@ static int ht16k33_keypad_probe(struct i2c_client *client,
err = matrix_keypad_parse_of_params(&client->dev, &rows, &cols);
if (err)
return err;
if (rows > HT16K33_MATRIX_KEYPAD_MAX_ROWS ||
cols > HT16K33_MATRIX_KEYPAD_MAX_COLS) {
dev_err(&client->dev, "%u rows or %u cols out of range in DT\n",
rows, cols);
return -ERANGE;
}
keypad->rows = rows;
keypad->cols = cols;