In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields.
Use memset_startat() so memset() doesn't get confused about writing beyond the destination member that is intended to be the starting point of zeroing through the end of the struct.
Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Signed-off-by: Kees Cook keescook@chromium.org --- drivers/hwtracing/intel_th/msu.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index 432ade0842f6..70a07b4e9967 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -658,13 +658,11 @@ static void msc_buffer_clear_hw_header(struct msc *msc)
list_for_each_entry(win, &msc->win_list, entry) { unsigned int blk; - size_t hw_sz = sizeof(struct msc_block_desc) - - offsetof(struct msc_block_desc, hw_tag);
for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) { struct msc_block_desc *bdesc = sg_virt(sg);
- memset(&bdesc->hw_tag, 0, hw_sz); + memset_startat(bdesc, 0, hw_tag); } } }