nvmem: imx-ocotp: fix MAC address byte length

commit 2aa4ad626ee7f817a8f4715a47b318cfdc1714c9 upstream.

The commit "13bcd440f2ff nvmem: core: verify cell's raw_len" caused an
extension of the "mac-address" cell from 6 to 8 bytes due to word_size
of 4 bytes. This led to a required byte swap of the full buffer length,
which caused truncation of the mac-address when read.

Previously, the mac-address was incorrectly truncated from
70:B3:D5:14:E9:0E to 00:00:70:B3:D5:14.

Fix the issue by swapping only the first 6 bytes to correctly pass the
mac-address to the upper layers.

Fixes: 13bcd440f2ff ("nvmem: core: verify cell's raw_len")
Cc: stable@vger.kernel.org
Signed-off-by: Steffen Bätz <steffen@innosonix.de>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Srinivas Kandagatla <srini@kernel.org>
Link: https://lore.kernel.org/r/20250712181729.6495-3-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Steffen Bätz
2025-07-12 19:17:27 +01:00
committed by Greg Kroah-Hartman
parent 0cd051cb58
commit 0f6f30f5b0
2 changed files with 8 additions and 2 deletions

View File

@@ -12,6 +12,7 @@
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/if_ether.h> /* ETH_ALEN */
enum fuse_type {
FUSE_FSB = 1,
@@ -114,9 +115,11 @@ static int imx_ocotp_cell_pp(void *context, const char *id, int index,
int i;
/* Deal with some post processing of nvmem cell data */
if (id && !strcmp(id, "mac-address"))
if (id && !strcmp(id, "mac-address")) {
bytes = min(bytes, ETH_ALEN);
for (i = 0; i < bytes / 2; i++)
swap(buf[i], buf[bytes - i - 1]);
}
return 0;
}

View File

@@ -23,6 +23,7 @@
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/if_ether.h> /* ETH_ALEN */
#define IMX_OCOTP_OFFSET_B0W0 0x400 /* Offset from base address of the
* OTP Bank0 Word0
@@ -227,9 +228,11 @@ static int imx_ocotp_cell_pp(void *context, const char *id, int index,
int i;
/* Deal with some post processing of nvmem cell data */
if (id && !strcmp(id, "mac-address"))
if (id && !strcmp(id, "mac-address")) {
bytes = min(bytes, ETH_ALEN);
for (i = 0; i < bytes / 2; i++)
swap(buf[i], buf[bytes - i - 1]);
}
return 0;
}