Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
While there, use struct_size() helper, instead of the open-coded
version, to calculate the size for the allocation of the whole
flexible structure including, of course, the flexible-array member.
This code was found with the help of Coccinelle, and audited and
fixed manually.
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
net/mac80211/ieee80211_i.h | 2 +-
net/mac80211/util.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e92eaf835ee0..0d3d386445c5 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1746,7 +1746,7 @@ struct ieee802_11_elems {
*/
size_t scratch_len;
u8 *scratch_pos;
- u8 scratch[];
+ u8 scratch[] __counted_by(scratch_len);
};
static inline struct ieee80211_local *hw_to_local(
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 98a3bffc6991..a91b0e7795a4 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1612,7 +1612,7 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
int nontransmitted_profile_len = 0;
size_t scratch_len = 3 * params->len;
- elems = kzalloc(sizeof(*elems) + scratch_len, GFP_ATOMIC);
+ elems = kzalloc(struct_size(elems, scratch, scratch_len), GFP_ATOMIC);
if (!elems)
return NULL;
elems->ie_start = params->start;
--
2.34.1
