diff options
| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 14:26:47 -0500 |
|---|---|---|
| committer | Kalle Valo <kvalo@codeaurora.org> | 2020-05-12 11:56:55 +0300 |
| commit | bd7db3021aa7a31f7d5122af1a863e66c75f88f5 (patch) | |
| tree | 311d1a58cba98643d43a677787672fe662a9a1b4 /drivers | |
| parent | 55bb8a2b01a3f1531a5154457ec1c7041f5c6f9e (diff) | |
rndis_wlan: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200507192647.GA16710@embeddedor
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/wireless/rndis_wlan.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c index 78a4325bfe1b..8852a1832951 100644 --- a/drivers/net/wireless/rndis_wlan.c +++ b/drivers/net/wireless/rndis_wlan.c @@ -201,7 +201,7 @@ struct ndis_80211_pmkid_candidate { struct ndis_80211_pmkid_cand_list { __le32 version; __le32 num_candidates; - struct ndis_80211_pmkid_candidate candidate_list[0]; + struct ndis_80211_pmkid_candidate candidate_list[]; } __packed; struct ndis_80211_status_indication { @@ -246,12 +246,12 @@ struct ndis_80211_bssid_ex { __le32 net_infra; u8 rates[NDIS_802_11_LENGTH_RATES_EX]; __le32 ie_length; - u8 ies[0]; + u8 ies[]; } __packed; struct ndis_80211_bssid_list_ex { __le32 num_items; - struct ndis_80211_bssid_ex bssid[0]; + struct ndis_80211_bssid_ex bssid[]; } __packed; struct ndis_80211_fixed_ies { @@ -327,7 +327,7 @@ struct ndis_80211_bssid_info { struct ndis_80211_pmkid { __le32 length; __le32 bssid_info_count; - struct ndis_80211_bssid_info bssid_info[0]; + struct ndis_80211_bssid_info bssid_info[]; } __packed; /* |