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, 27 insertions, 0 deletions

diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
new file mode 100644
index 000000000..c729bc936
--- /dev/null
+++ b/scripts/mod/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS_REMOVE_empty.o += $(CC_FLAGS_LTO)
+
+hostprogs-always-y	+= modpost mk_elfconfig
+always-y		+= empty.o
+
+modpost-objs	:= modpost.o file2alias.o sumversion.o symsearch.o
+
+devicetable-offsets-file := devicetable-offsets.h
+
+$(obj)/$(devicetable-offsets-file): $(obj)/devicetable-offsets.s FORCE
+	$(call filechk,offsets,__DEVICETABLE_OFFSETS_H__)
+
+targets += $(devicetable-offsets-file) devicetable-offsets.s
+
+# dependencies on generated files need to be listed explicitly
+
+$(obj)/modpost.o $(obj)/file2alias.o $(obj)/sumversion.o $(obj)/symsearch.o: $(obj)/elfconfig.h
+$(obj)/file2alias.o: $(obj)/$(devicetable-offsets-file)
+
+quiet_cmd_elfconfig = MKELF   $@
+      cmd_elfconfig = $(obj)/mk_elfconfig < $< > $@
+
+$(obj)/elfconfig.h: $(obj)/empty.o $(obj)/mk_elfconfig FORCE
+	$(call if_changed,elfconfig)
+
+targets += elfconfig.h