One-element arrays are deprecated, and we are replacing them with flexible array members instead. However, in this case it seems those one-element arrays have never actually been used as fake flexible arrays.

See this code that dates from Linux-2.6.12-rc2 initial git repository build (commit 1da177e4c3f4 ("Linux-2.6.12-rc2")):

sound/pci/mixart/mixart_core.h: 215 struct mixart_stream_state_req 216 { 217 u32 delayed; 218 u64 scheduler; 219 u32 reserved4np[3]; 220 u32 stream_count; /* set to 1 for instance */ 221 struct mixart_flow_info stream_info; /* could be an array[stream_count] */ 222 } __attribute__((packed));

sound/pci/mixart/mixart.c: 388 389 memset(&stream_state_req, 0, sizeof(stream_state_req)); 390 stream_state_req.stream_count = 1; 391 stream_state_req.stream_info.stream_desc.uid_pipe = stream->pipe->group_uid; 392 stream_state_req.stream_info.stream_desc.stream_idx = stream->substream->number; 393

So, taking the code above as example, replace multiple one-element arrays with simple object declarations, and refactor the rest of the code, accordingly.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines on memcpy() and help us make progress towards globally enabling -fstrict-flex-arrays=3 [1].

This results in no differences in binary output.

Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/296 Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1] Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org --- Changes in v2: - Keep the code comments (by Takashi Iwai) and explicitly mention that the objects could be arrays, in theory.

v1: - Link: https://lore.kernel.org/linux-hardening/ZGVlcpuvx1rSOMP8@work/

sound/pci/mixart/mixart.c | 8 ++++---- sound/pci/mixart/mixart_core.h | 7 +++---- 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/sound/pci/mixart/mixart.c b/sound/pci/mixart/mixart.c index 1b078b789604..7ceaf6a7a77e 100644 --- a/sound/pci/mixart/mixart.c +++ b/sound/pci/mixart/mixart.c @@ -98,7 +98,7 @@ static int mixart_set_pipe_state(struct mixart_mgr *mgr,

memset(&group_state, 0, sizeof(group_state)); group_state.pipe_count = 1; - group_state.pipe_uid[0] = pipe->group_uid; + group_state.pipe_uid = pipe->group_uid;

if(start) request.message_id = MSG_STREAM_START_STREAM_GRP_PACKET; @@ -185,7 +185,7 @@ static int mixart_set_clock(struct mixart_mgr *mgr, clock_properties.clock_mode = CM_STANDALONE; clock_properties.frequency = rate; clock_properties.nb_callers = 1; /* only one entry in uid_caller ! */ - clock_properties.uid_caller[0] = pipe->group_uid; + clock_properties.uid_caller = pipe->group_uid;

dev_dbg(&mgr->pci->dev, "mixart_set_clock to %d kHz\n", rate);

@@ -565,8 +565,8 @@ static int mixart_set_format(struct mixart_stream *stream, snd_pcm_format_t form

stream_param.pipe_count = 1; /* set to 1 */ stream_param.stream_count = 1; /* set to 1 */ - stream_param.stream_desc[0].uid_pipe = stream->pipe->group_uid; - stream_param.stream_desc[0].stream_idx = stream->substream->number; + stream_param.stream_desc.uid_pipe = stream->pipe->group_uid; + stream_param.stream_desc.stream_idx = stream->substream->number;

request.message_id = MSG_STREAM_SET_INPUT_STAGE_PARAM; request.uid = (struct mixart_uid){0,0}; diff --git a/sound/pci/mixart/mixart_core.h b/sound/pci/mixart/mixart_core.h index 2f0e29ed5d63..d39233e0e070 100644 --- a/sound/pci/mixart/mixart_core.h +++ b/sound/pci/mixart/mixart_core.h @@ -231,7 +231,7 @@ struct mixart_group_state_req u64 scheduler; u32 reserved4np[2]; u32 pipe_count; /* set to 1 for instance */ - struct mixart_uid pipe_uid[1]; /* could be an array[pipe_count] */ + struct mixart_uid pipe_uid; /* could be an array[pipe_count], in theory */ } __attribute__((packed));

struct mixart_group_state_resp @@ -314,7 +314,7 @@ struct mixart_clock_properties u32 format; u32 board_mask; u32 nb_callers; /* set to 1 (see below) */ - struct mixart_uid uid_caller[1]; + struct mixart_uid uid_caller; } __attribute__((packed));

struct mixart_clock_properties_resp @@ -401,8 +401,7 @@ struct mixart_stream_param_desc u32 reserved4np[3]; u32 pipe_count; /* set to 1 (array size !) */ u32 stream_count; /* set to 1 (array size !) */ - struct mixart_txx_stream_desc stream_desc[1]; /* only one stream per command, but this could be an array */ - + struct mixart_txx_stream_desc stream_desc; /* only one stream per command, but this could be an array, in theory */ } __attribute__((packed));