usb: gadget: f_uac1_legacy: validate bRequest index in generic_{set,get}_cmdgrafted

generic_set_cmd() and generic_get_cmd() use the low nibble of
ctrl->bRequest as an index into con->data[]:

    u8 cmd = (ctrl->bRequest & 0x0F);  /* 0 .. 15 */
    ...
    con->data[cmd] = value;            /* OOB when cmd >= 5 */

struct usb_audio_control (include/linux/usb/audio.h) declares data as
a 5-element array, so indices 5 through 15 write (or read) up to 44
bytes past the end of the array on the heap.

A malicious USB host can craft a class-specific SET_CUR / GET_CUR
request with an arbitrary bRequest value, triggering the out-of-bounds
access from an IRQ completion handler with no further preconditions.

Add an ARRAY_SIZE() guard to both functions.

Fixes: c47d7b09891a ("USB: audio: add USB audio class definitions")
Cc: stable <stable@kernel.org>
Reviewed-by: Weibin Liu <liuwb@xiaopeng.com>
Signed-off-by: Liu Chao <liuc63@xiaopeng.com>
Reviewed-by: Ivy Lopez <skunkolee@gmail.com>
Link: https://patch.msgid.link/20260921072551.3708191-1-liuc63@xiaopeng.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/arch/powerpc/boot/stdlib.c b/arch/powerpc/boot/stdlib.c
new file mode 100644
index 000000000..868b019d6
--- /dev/null
+++ b/arch/powerpc/boot/stdlib.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * stdlib functions
+ *
+ * Author: Scott Wood <scottwood@freescale.com>
+ *
+ * Copyright (c) 2007 Freescale Semiconductor, Inc.
+ */
+
+#include "stdlib.h"
+
+/* Not currently supported: leading whitespace, sign, 0x prefix, zero base */
+unsigned long long int strtoull(const char *ptr, char **end, int base)
+{
+	unsigned long long ret = 0;
+
+	if (base > 36)
+		goto out;
+
+	while (*ptr) {
+		int digit;
+
+		if (*ptr >= '0' && *ptr <= '9' && *ptr < '0' + base)
+			digit = *ptr - '0';
+		else if (*ptr >= 'A' && *ptr < 'A' + base - 10)
+			digit = *ptr - 'A' + 10;
+		else if (*ptr >= 'a' && *ptr < 'a' + base - 10)
+			digit = *ptr - 'a' + 10;
+		else
+			break;
+
+		ret *= base;
+		ret += digit;
+		ptr++;
+	}
+
+out:
+	if (end)
+		*end = (char *)ptr;
+
+	return ret;
+}