io_create_region_mmap_safe() protects publishing of a region against concurrent mmap calls, however we should also protect against it when removing a region. There is a gap io_register_mem_region() where it safely publishes a region, but then copy_to_user goes wrong and it unsafely frees the region. Cc: stable@vger.kernel.org Fixes: 087f997870a94 ("io_uring/memmap: implement mmap for regions") Signed-off-by: Pavel Begunkov --- io_uring/register.c | 1 + 1 file changed, 1 insertion(+) diff --git a/io_uring/register.c b/io_uring/register.c index 43f04c47522c..58d43d624856 100644 --- a/io_uring/register.c +++ b/io_uring/register.c @@ -613,6 +613,7 @@ static int io_register_mem_region(struct io_ring_ctx *ctx, void __user *uarg) if (ret) return ret; if (copy_to_user(rd_uptr, &rd, sizeof(rd))) { + guard(mutex)(&ctx->mmap_lock); io_free_region(ctx, &ctx->param_region); return -EFAULT; } -- 2.49.0