Merge: CVE-2024-58069: rtc: pcf85063: fix potential OOB write in PCF85063 NVMEM read

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6528

JIRA: https://issues.redhat.com/browse/RHEL-82456
CVE: CVE-2024-58069

```
commit 3ab8c5e
Author: Oleksij Rempel <[email protected]>
Date:   Wed Dec 18 20:34:58 2024 +0100

    rtc: pcf85063: fix potential OOB write in PCF85063 NVMEM read

    The nvmem interface supports variable buffer sizes, while the regmap
    interface operates with fixed-size storage. If an nvmem client uses a
    buffer size less than 4 bytes, regmap_read will write out of bounds
    as it expects the buffer to point at an unsigned int.

    Fix this by using an intermediary unsigned int to hold the value.

    Fixes: fadfd09 ("rtc: pcf85063: add nvram support")
    Signed-off-by: Oleksij Rempel <[email protected]>
    Signed-off-by: Ahmad Fatoum <[email protected]>
    Link: https://lore.kernel.org/r/20241218-rtc-pcf85063-stack-corruption-v1-1-12fd0ee0f046@pengutronix.de
    Signed-off-by: Alexandre Belloni <[email protected]>```

Signed-off-by: CKI Backport Bot <[email protected]>

---

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Approved-by: Daniel Horak <[email protected]>
Approved-by: Tony Camuso <[email protected]>
Approved-by: Lucas Zampieri <[email protected]>
Approved-by: John W. Linville <[email protected]>
Approved-by: Myron Stowe <[email protected]>
Approved-by: CKI KWF Bot <[email protected]>

Merged-by: Augusto Caringi <[email protected]>

Author: caringi

drivers/rtc/rtc-pcf85063.c

@@ -322,7 +322,16 @@ static const struct rtc_class_ops pcf85063_rtc_ops = {
 static int pcf85063_nvmem_read(void *priv, unsigned int offset,
 			       void *val, size_t bytes)
 {
-	return regmap_read(priv, PCF85063_REG_RAM, val);
+	unsigned int tmp;
+	int ret;
+
+	ret = regmap_read(priv, PCF85063_REG_RAM, &tmp);
+	if (ret < 0)
+		return ret;
+
+	*(u8 *)val = tmp;
+
+	return 0;
 }
 
 static int pcf85063_nvmem_write(void *priv, unsigned int offset,