* [PATCH 6.6 1362/1674] usb: gadget: f_midi: Annotate struct f_midi with __counted_by
[not found] <20261017160431.119607952@linuxfoundation.org>
@ 2026-10-17 16:00 ` Greg Kroah-Hartman
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From: Greg Kroah-Hartman @ 2026-10-17 16:00 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, John Keeping, Peter Chen, Hulk Robot,
Allen Pais, Will McVicker, Davidlohr Bueso, Zhang Qilong,
linux-usb, Gustavo A. R. Silva, Kees Cook, Sasha Levin
6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kees Cook <keescook@chromium.org>
[ Upstream commit 182717026e2c8e6cc3b5757f601c3fee15f64ecb ]
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
As found with Coccinelle[1], add __counted_by for struct f_midi.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.
[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: John Keeping <john@keeping.me.uk>
Cc: Peter Chen <peter.chen@nxp.com>
Cc: Hulk Robot <hulkci@huawei.com>
Cc: Allen Pais <allen.lkml@gmail.com>
Cc: Will McVicker <willmcvicker@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Zhang Qilong <zhangqilong3@huawei.com>
Cc: linux-usb@vger.kernel.org
Reviewed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230915195938.never.611-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Stable-dep-of: 7e07d3e4c389 ("usb: gadget: f_midi: initialize work in f_midi_alloc()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/gadget/function/f_midi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 680651e91a523..48c87f5b1a4e1 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -99,7 +99,7 @@ struct f_midi {
unsigned int in_last_port;
unsigned char free_ref;
- struct gmidi_in_port in_ports_array[/* in_ports */];
+ struct gmidi_in_port in_ports_array[] __counted_by(in_ports);
};
static inline struct f_midi *func_to_midi(struct usb_function *f)
@@ -1359,6 +1359,7 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
status = -ENOMEM;
goto setup_fail;
}
+ midi->in_ports = opts->in_ports;
for (i = 0; i < opts->in_ports; i++)
midi->in_ports_array[i].cable = i;
@@ -1369,7 +1370,6 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
status = -ENOMEM;
goto midi_free;
}
- midi->in_ports = opts->in_ports;
midi->out_ports = opts->out_ports;
midi->index = opts->index;
midi->buflen = opts->buflen;
--
2.53.0
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