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Date: Mon, 25 Mar 2024 19:56:10 -0600
From: "Gustavo A. R. Silva" <gustavoars@kernel.org>
To: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: linux1394-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-hardening@vger.kernel.org
Subject: [PATCH][next] firewire: Annotate struct fw_iso_packet with
 __counted_by()
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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 via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 include/linux/firewire.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index dd9f2d765e68..00abe0e5d602 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -463,7 +463,8 @@ struct fw_iso_packet {
 	u32 tag:2;		/* tx: Tag in packet header		*/
 	u32 sy:4;		/* tx: Sy in packet header		*/
 	u32 header_length:8;	/* Length of immediate header		*/
-	u32 header[];		/* tx: Top of 1394 isoch. data_block	*/
+				/* tx: Top of 1394 isoch. data_block    */
+	u32 header[] __counted_by(header_length);
 };
 
 #define FW_ISO_CONTEXT_TRANSMIT			0
-- 
2.34.1