net: wwan: t7xx: Add __counted_by for struct t7xx_fsm_event and use struct_size()

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@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gustavo A. R. Silva 2023-10-09 15:46:18 -06:00 committed by David S. Miller
parent 13266ad9e5
commit 2dd3071892
2 changed files with 3 additions and 2 deletions

View File

@ -445,7 +445,8 @@ int t7xx_fsm_append_event(struct t7xx_fsm_ctl *ctl, enum t7xx_fsm_event_state ev
return -EINVAL;
}
event = kmalloc(sizeof(*event) + length, in_interrupt() ? GFP_ATOMIC : GFP_KERNEL);
event = kmalloc(struct_size(event, data, length),
in_interrupt() ? GFP_ATOMIC : GFP_KERNEL);
if (!event)
return -ENOMEM;

View File

@ -102,7 +102,7 @@ struct t7xx_fsm_event {
struct list_head entry;
enum t7xx_fsm_event_state event_id;
unsigned int length;
unsigned char data[];
unsigned char data[] __counted_by(length);
};
struct t7xx_fsm_command {