firewire: Annotate struct fw_iso_packet with __counted_by()

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>
Link: https://lore.kernel.org/r/ZgIrOuR3JI/jzqoH@neat
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index dd9f2d765e68b27fbc016f2c34571dff8c94c500..00abe0e5d602bc8d51545aae2bc3c60c6f0c9f4f 100644 (file)
--- 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