[PATCH] wifi: brcmfmac: Replace 1-element arrays with flexible arrays

Juerg Haefliger
2023-09-13T06:54:57Z

Since commit 2d47c6956ab3 ("ubsan: Tighten UBSAN_BOUNDS on GCC"),
UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking
'element' and 'channel_list' will trigger warnings, so make them proper
flexible arrays.

False positive warnings were:

UBSAN: array-index-out-of-bounds in drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:6984:20
index 1 is out of range for type '__le32 [1]'

UBSAN: array-index-out-of-bounds in drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:1126:27
index 1 is out of range for type '__le16 [1]'

for these lines of code:

6884 ch.chspec = (u16)le32_to_cpu(list->element[i]);

1126 params_le->channel_list[i] = cpu_to_le16(chanspec);

Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
---
.../wireless/broadcom/brcm80211/brcmfmac/fwil_types.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h
index bece26741d3a..ed723a5b5d54 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h
@@ -442,7 +442,12 @@ struct brcmf_scan_params_v2_le {
* fixed parameter portion is assumed, otherwise
* ssid in the fixed portion is ignored
*/
- __le16 channel_list[1]; /* list of chanspecs */
+ union {
+ __le16 padding; /* Reserve space for at least 1 entry for abort
+ * which uses an on stack brcmf_scan_params_v2_le
+ */
+ DECLARE_FLEX_ARRAY(__le16, channel_list); /* chanspecs */
+ };
};

struct brcmf_scan_results {
@@ -702,7 +707,7 @@ struct brcmf_sta_info_le {

struct brcmf_chanspec_list {
__le32 count; /* # of entries */
- __le32 element[1]; /* variable length uint32 list */
+ DECLARE_FLEX_ARRAY(__le32, element); /* variable length uint32 list */
};

/*
--
2.39.2