From: Kees Cook keescook@chromium.org
commit e3128a9d482cff9cc2a826adec5e1f7acb922b8f upstream.
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 Link: https://lore.kernel.org/r/20211207063538.2767954-1-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/wireless/ath/ath6kl/htc.h | 15 +++++++++++---- drivers/net/wireless/ath/ath6kl/htc_mbox.c | 15 ++++++--------- 2 files changed, 17 insertions(+), 13 deletions(-)
--- 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; + 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; + /* length of data (including trailer) that follows the header */ + __le16 payld_len;
+ }; + u32 word; + }; + ); /* end of 4-byte lookahead */
u8 ctrl[2]; --- 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(str 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 rx wait ctrl look_ahead 0x%X\n", look_ahead.word);
- htc_hdr = (struct htc_frame_hdr *)&look_ahead; - - 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_c 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;