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, 45 insertions, 0 deletions

diff --git a/scripts/objdump-func b/scripts/objdump-func
new file mode 100755
index 000000000..7b15b873d
--- /dev/null
+++ b/scripts/objdump-func
@@ -0,0 +1,45 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Disassemble a single function.
+#
+# usage: objdump-func <file> <func> [<func> ...]
+
+set -o errexit
+set -o nounset
+
+OBJDUMP="${CROSS_COMPILE:-}objdump"
+
+command -v gawk >/dev/null 2>&1 || die "gawk isn't installed"
+
+usage() {
+	echo "usage: objdump-func <file> <func> [<func> ...]" >&2
+	exit 1
+}
+
+[[ $# -lt 2 ]] && usage
+
+OBJ=$1; shift
+FUNCS=("$@")
+
+${OBJDUMP} -wdr $OBJ | gawk -M -v _funcs="${FUNCS[*]}" '
+	BEGIN { split(_funcs, funcs); }
+	/^$/ { func_match=0; }
+	/<.*>:/ {
+		f = gensub(/.*<(.*)>:/, "\\1", 1);
+		for (i in funcs) {
+			# match compiler-added suffixes like ".cold", etc
+			if (f ~ "^" funcs[i] "(\\..*)?") {
+				func_match = 1;
+				base = strtonum("0x" $1);
+				break;
+			}
+		}
+	}
+	{
+		if (func_match) {
+			addr = strtonum("0x" $1);
+			printf("%04x ", addr - base);
+			print;
+		}
+	}'