wifi: rtw89: avoid reading out of bounds when loading TX power FW elements

Because the loop-expression will do one more time before getting false from
cond-expression, the original code copied one more entry size beyond valid
region.

Fix it by moving the entry copy to loop-body.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240902015803.20420-1-pkshih@realtek.com

diff --git a/drivers/net/wireless/realtek/rtw89/core.h b/drivers/net/wireless/realtek/rtw89/core.h
index 4091c8838bc5d95158bf8f70dd04203676ccef93..4ed9034fdb46416fb30b611a90d25ca9c45b2547 100644 (file)
--- a/drivers/net/wireless/realtek/rtw89/core.h
+++ b/drivers/net/wireless/realtek/rtw89/core.h
@@ -3978,16 +3978,22 @@ struct rtw89_txpwr_conf {
        const void *data;
 };
 
+static inline bool rtw89_txpwr_entcpy(void *entry, const void *cursor, u8 size,
+                                     const struct rtw89_txpwr_conf *conf)
+{
+       u8 valid_size = min(size, conf->ent_sz);
+
+       memcpy(entry, cursor, valid_size);
+       return true;
+}
+
 #define rtw89_txpwr_conf_valid(conf) (!!(conf)->data)
 
 #define rtw89_for_each_in_txpwr_conf(entry, cursor, conf) \
-       for (typecheck(const void *, cursor), (cursor) = (conf)->data, \
-            memcpy(&(entry), cursor, \
-                   min_t(u8, sizeof(entry), (conf)->ent_sz)); \
+       for (typecheck(const void *, cursor), (cursor) = (conf)->data; \
             (cursor) < (conf)->data + (conf)->num_ents * (conf)->ent_sz; \
-            (cursor) += (conf)->ent_sz, \
-            memcpy(&(entry), cursor, \
-                   min_t(u8, sizeof(entry), (conf)->ent_sz)))
+            (cursor) += (conf)->ent_sz) \
+               if (rtw89_txpwr_entcpy(&(entry), cursor, sizeof(entry), conf))
 
 struct rtw89_txpwr_byrate_data {
        struct rtw89_txpwr_conf conf;