On Mon, Oct 09, 2023 at 03:46:18PM -0600, Gustavo A. R. Silva wrote: > 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 <[email protected]>
Looks right to me. Reviewed-by: Kees Cook <[email protected]> -Kees > --- > drivers/net/wwan/t7xx/t7xx_state_monitor.c | 3 ++- > drivers/net/wwan/t7xx/t7xx_state_monitor.h | 2 +- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wwan/t7xx/t7xx_state_monitor.c > b/drivers/net/wwan/t7xx/t7xx_state_monitor.c > index 80edb8e75a6a..0bc97430211b 100644 > --- a/drivers/net/wwan/t7xx/t7xx_state_monitor.c > +++ b/drivers/net/wwan/t7xx/t7xx_state_monitor.c > @@ -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; > > diff --git a/drivers/net/wwan/t7xx/t7xx_state_monitor.h > b/drivers/net/wwan/t7xx/t7xx_state_monitor.h > index b6e76f3903c8..b0b3662ae6d7 100644 > --- a/drivers/net/wwan/t7xx/t7xx_state_monitor.h > +++ b/drivers/net/wwan/t7xx/t7xx_state_monitor.h > @@ -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 { > -- > 2.34.1 > > -- Kees Cook
