Move the `struct ieee80211_chanctx_conf conf` to the end of
`struct ieee80211_chanctx` and fix a memory corruption bug
triggered in `hwsim_set_chanctx_magic()`: `radar_detected`
is being overwritten when `cp->magic = HWSIM_CHANCTX_MAGIC;`
See the function call sequence below:
drv_add_chanctx(... struct ieee80211_chanctx *ctx) ->
local->ops->add_chanctx(&local->hw, &ctx->conf) ->
mac80211_hwsim_add_chanctx(... struct ieee80211_chanctx_conf *ctx) ->
hwsim_set_chanctx_magic(ctx)
Also, add a code comment to try to prevent people from introducing
new members after `struct ieee80211_chanctx_conf conf`. Notice that
`struct ieee80211_chanctx_conf` is a flexible structure --a structure
that contains a flexible-array member, so it should always be at
the end of any other containing structures.
This change also fixes 50 of the following warnings:
net/mac80211/ieee80211_i.h:895:39: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
Fixes: bca8bc0399ac ("wifi: mac80211: handle ieee80211_radar_detected() for MLO")
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
Changes in v2:
- Add `Fixes:` tag. (Johannes)
- Update Subject line and changelog text to better reflect
the severity of this change.
v1:
- Link: https://lore.kernel.org/linux-hardening/Zxv7KtPEy1kvnTPM@kspp/
net/mac80211/ieee80211_i.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e7815ffeaf30..c65adbdf2166 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -892,9 +892,10 @@ struct ieee80211_chanctx {
/* temporary data for search algorithm etc. */
struct ieee80211_chan_req req;
- struct ieee80211_chanctx_conf conf;
-
bool radar_detected;
+
+ /* MUST be last - ends in a flexible-array member. */
+ struct ieee80211_chanctx_conf conf;
};
struct mac80211_qos_map {
--
2.34.1
