From 2dd3071892202ccaec3c59afc65c5b88357e73c9 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 9 Oct 2023 15:46:18 -0600 Subject: [PATCH] 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 Reviewed-by: Kees Cook Signed-off-by: David S. Miller --- 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 {