| Message ID | 20211207063538.2767954-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | e3128a9d482cff9cc2a826adec5e1f7acb922b8f |
| Headers | show |
| Series | ath6kl: Use struct_group() to avoid size-mismatched casting | expand |
Kees Cook <keescook@chromium.org> wrote: > In builds with -Warray-bounds, casts from smaller objects to larger > objects will produce warnings. These can be overly conservative, but since > -Warray-bounds has been finding legitimate bugs, it is desirable to turn > it on globally. Instead of casting a u32 to a larger object, redefine > the u32 portion of the header to a separate struct that can be used for > both u32 operations and the distinct header fields. Silences this warning: > > drivers/net/wireless/ath/ath6kl/htc_mbox.c: In function 'htc_wait_for_ctrl_msg': > drivers/net/wireless/ath/ath6kl/htc_mbox.c:2275:20: error: array subscript 'struct htc_frame_hdr[0]' is partly outside array bounds of 'u32[1]' {aka 'unsigned int[1]'} [-Werror=array-bounds] > 2275 | if (htc_hdr->eid != ENDPOINT_0) > | ^~ > drivers/net/wireless/ath/ath6kl/htc_mbox.c:2264:13: note: while referencing 'look_ahead' > 2264 | u32 look_ahead; > | ^~~~~~~~~~ > > This change results in no executable instruction differences. > > Signed-off-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com> Patch applied to ath-next branch of ath.git, thanks. e3128a9d482c ath6kl: Use struct_group() to avoid size-mismatched casting
diff --git a/drivers/net/wireless/ath/ath6kl/htc.h b/drivers/net/wireless/ath/ath6kl/htc.h index 112d8a9b8d43..d3534a29c4f0 100644 --- a/drivers/net/wireless/ath/ath6kl/htc.h +++ b/drivers/net/wireless/ath/ath6kl/htc.h @@ -153,12 +153,19 @@ * implementations. */ struct htc_frame_hdr { - u8 eid; - u8 flags; - - /* length of data (including trailer) that follows the header */ - __le16 payld_len; - + struct_group_tagged(htc_frame_look_ahead, header, + union { + struct { + u8 eid; + u8 flags; + + /* length of data (including trailer) that follows the header */ + __le16 payld_len; + + }; + u32 word; + }; + ); /* end of 4-byte lookahead */ u8 ctrl[2]; diff --git a/drivers/net/wireless/ath/ath6kl/htc_mbox.c b/drivers/net/wireless/ath/ath6kl/htc_mbox.c index 998947ef63b6..e3874421c4c0 100644 --- a/drivers/net/wireless/ath/ath6kl/htc_mbox.c +++ b/drivers/net/wireless/ath/ath6kl/htc_mbox.c @@ -2260,19 +2260,16 @@ int ath6kl_htc_rxmsg_pending_handler(struct htc_target *target, static struct htc_packet *htc_wait_for_ctrl_msg(struct htc_target *target) { struct htc_packet *packet = NULL; - struct htc_frame_hdr *htc_hdr; - u32 look_ahead; + struct htc_frame_look_ahead look_ahead; - if (ath6kl_hif_poll_mboxmsg_rx(target->dev, &look_ahead, + if (ath6kl_hif_poll_mboxmsg_rx(target->dev, &look_ahead.word, HTC_TARGET_RESPONSE_TIMEOUT)) return NULL; ath6kl_dbg(ATH6KL_DBG_HTC, - "htc rx wait ctrl look_ahead 0x%X\n", look_ahead); - - htc_hdr = (struct htc_frame_hdr *)&look_ahead; + "htc rx wait ctrl look_ahead 0x%X\n", look_ahead.word); - if (htc_hdr->eid != ENDPOINT_0) + if (look_ahead.eid != ENDPOINT_0) return NULL; packet = htc_get_control_buf(target, false); @@ -2281,8 +2278,8 @@ static struct htc_packet *htc_wait_for_ctrl_msg(struct htc_target *target) return NULL; packet->info.rx.rx_flags = 0; - packet->info.rx.exp_hdr = look_ahead; - packet->act_len = le16_to_cpu(htc_hdr->payld_len) + HTC_HDR_LENGTH; + packet->info.rx.exp_hdr = look_ahead.word; + packet->act_len = le16_to_cpu(look_ahead.payld_len) + HTC_HDR_LENGTH; if (packet->act_len > packet->buf_len) goto fail_ctrl_rx;
In builds with -Warray-bounds, casts from smaller objects to larger objects will produce warnings. These can be overly conservative, but since -Warray-bounds has been finding legitimate bugs, it is desirable to turn it on globally. Instead of casting a u32 to a larger object, redefine the u32 portion of the header to a separate struct that can be used for both u32 operations and the distinct header fields. Silences this warning: drivers/net/wireless/ath/ath6kl/htc_mbox.c: In function 'htc_wait_for_ctrl_msg': drivers/net/wireless/ath/ath6kl/htc_mbox.c:2275:20: error: array subscript 'struct htc_frame_hdr[0]' is partly outside array bounds of 'u32[1]' {aka 'unsigned int[1]'} [-Werror=array-bounds] 2275 | if (htc_hdr->eid != ENDPOINT_0) | ^~ drivers/net/wireless/ath/ath6kl/htc_mbox.c:2264:13: note: while referencing 'look_ahead' 2264 | u32 look_ahead; | ^~~~~~~~~~ This change results in no executable instruction differences. Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/net/wireless/ath/ath6kl/htc.h | 19 +++++++++++++------ drivers/net/wireless/ath/ath6kl/htc_mbox.c | 15 ++++++--------- 2 files changed, 19 insertions(+), 15 deletions(-)