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, 75 insertions, 0 deletions

diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
new file mode 100755
index 000000000..2f1d1767c
--- /dev/null
+++ b/scripts/headers_install.sh
@@ -0,0 +1,75 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+if [ $# -ne 2 ]
+then
+	echo "Usage: headers_install.sh INFILE OUTFILE"
+	echo
+	echo "Prepares kernel header files for use by user space, by removing"
+	echo "all compiler.h definitions and #includes, removing any"
+	echo "#ifdef __KERNEL__ sections, and putting __underscores__ around"
+	echo "asm/inline/volatile keywords."
+	echo
+	echo "INFILE: header file to operate on"
+	echo "OUTFILE: output file which the processed header is written to"
+
+	exit 1
+fi
+
+# Grab arguments
+INFILE=$1
+OUTFILE=$2
+TMPFILE=$OUTFILE.tmp
+
+trap 'rm -f $OUTFILE $TMPFILE' EXIT
+
+# SPDX-License-Identifier with GPL variants must have "WITH Linux-syscall-note"
+if [ -n "$(sed -n -e "/SPDX-License-Identifier:.*GPL-/{/WITH Linux-syscall-note/!p}" $INFILE)" ]; then
+	echo "error: $INFILE: missing \"WITH Linux-syscall-note\" for SPDX-License-Identifier" >&2
+	exit 1
+fi
+
+sed -E -e '
+	s/([[:space:](])(__user|__force|__iomem)[[:space:]]/\1/g
+	s/__attribute_const__([[:space:]]|$)/\1/g
+	s@^#include <linux/compiler.h>@@
+	s/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g
+	s/(^|[[:space:](])(inline|asm|volatile)([[:space:](]|$)/\1__\2__\3/g
+	s@#(ifndef|define|endif[[:space:]]*/[*])[[:space:]]*_UAPI@#\1 @
+	s/__ASSEMBLY__/__ASSEMBLER__/g
+' $INFILE > $TMPFILE || exit 1
+
+scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ $TMPFILE > $OUTFILE
+[ $? -gt 1 ] && exit 1
+
+# Remove /* ... */ style comments, and find CONFIG_ references in code
+configs=$(sed -e '
+:comment
+	s:/\*[^*][^*]*:/*:
+	s:/\*\*\**\([^/]\):/*\1:
+	t comment
+	s:/\*\*/: :
+	t comment
+	/\/\*/! b check
+	N
+	b comment
+:print
+	P
+	D
+:check
+	s:^\(CONFIG_[[:alnum:]_]*\):\1\n:
+	t print
+	s:^[[:alnum:]_][[:alnum:]_]*::
+	s:^[^[:alnum:]_][^[:alnum:]_]*::
+	t check
+	d
+' $OUTFILE)
+
+for c in $configs
+do
+	echo "error: $INFILE: leak $c to user-space" >&2
+	exit 1
+done
+
+rm -f $TMPFILE
+trap - EXIT