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23 October 2021, 00:29:24 UTC
Revision d70674eeaa5efdefb99928691161578ae0a80316 authored by Arnd Bergmann on 25 October 2016, 15:55:04 UTC, committed by Greg Kroah-Hartman on 13 November 2016, 09:08:32 UTC 
iio: maxim_thermocouple: detect invalid storage size in read()
 
As found by gcc -Wmaybe-uninitialized, having a storage_bytes value other
than 2 or 4 will result in undefined behavior:

drivers/iio/temperature/maxim_thermocouple.c: In function 'maxim_thermocouple_read':
drivers/iio/temperature/maxim_thermocouple.c:141:5: error: 'ret' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This probably cannot happen, but returning -EINVAL here is appropriate
and makes gcc happy and the code more robust.

Fixes: 231147ee77f3 ("iio: maxim_thermocouple: Align 16 bit big endian value of raw reads")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
(cherry picked from commit 32cb7d27e65df9daa7cee8f1fdf7b259f214bee2)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 parent 68fae2f
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Tip revision: d70674eeaa5efdefb99928691161578ae0a80316 authored by Arnd Bergmann on 25 October 2016, 15:55:04 UTC
iio: maxim_thermocouple: detect invalid storage size in read()
Tip revision: d70674e
check_signature.c 
#include <linux/io.h>
#include <linux/export.h>

/**
 *	check_signature		-	find BIOS signatures
 *	@io_addr: mmio address to check
 *	@signature:  signature block
 *	@length: length of signature
 *
 *	Perform a signature comparison with the mmio address io_addr. This
 *	address should have been obtained by ioremap.
 *	Returns 1 on a match.
 */

int check_signature(const volatile void __iomem *io_addr,
			const unsigned char *signature, int length)
{
	while (length--) {
		if (readb(io_addr) != *signature)
			return 0;
		io_addr++;
		signature++;
	}
	return 1;
}
EXPORT_SYMBOL(check_signature);
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