For tests that need to allocate using vm_mmap() (e.g. usercopy and execve), provide the interface to have the allocation tracked by KUnit itself. This requires bringing up a placeholder userspace mm. This combines my earlier attempt at this with Mark Rutland's version[1]. Link: https://lore.kernel.org/lkml/20230321122514.1743889-2-mark.rutland@xxxxxxx/ [1] Co-developed-by: Mark Rutland <mark.rutland@xxxxxxx> Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- include/kunit/test.h | 17 ++++++ lib/kunit/test.c | 139 ++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 155 insertions(+), 1 deletion(-) diff --git a/include/kunit/test.h b/include/kunit/test.h index 61637ef32302..8c3835a6f282 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -478,6 +478,23 @@ static inline void *kunit_kcalloc(struct kunit *test, size_t n, size_t size, gfp return kunit_kmalloc_array(test, n, size, gfp | __GFP_ZERO); } +/** + * kunit_vm_mmap() - Allocate KUnit-tracked vm_mmap() area + * @test: The test context object. + * @file: struct file pointer to map from, if any + * @addr: desired address, if any + * @len: how many bytes to allocate + * @prot: mmap PROT_* bits + * @flag: mmap flags + * @offset: offset into @file to start mapping from. + * + * See vm_mmap() for more information. + */ +unsigned long kunit_vm_mmap(struct kunit *test, struct file *file, + unsigned long addr, unsigned long len, + unsigned long prot, unsigned long flag, + unsigned long offset); + void kunit_cleanup(struct kunit *test); void __printf(2, 3) kunit_log_append(struct string_stream *log, const char *fmt, ...); diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 1d1475578515..09194dbffb63 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -11,13 +11,14 @@ #include <kunit/test-bug.h> #include <kunit/attributes.h> #include <linux/kernel.h> +#include <linux/kthread.h> +#include <linux/mm.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/mutex.h> #include <linux/panic.h> #include <linux/sched/debug.h> #include <linux/sched.h> -#include <linux/mm.h> #include "debugfs.h" #include "device-impl.h" @@ -871,6 +872,142 @@ void kunit_kfree(struct kunit *test, const void *ptr) } EXPORT_SYMBOL_GPL(kunit_kfree); +struct kunit_vm_mmap_resource { + unsigned long addr; + size_t size; +}; + +/* vm_mmap() arguments */ +struct kunit_vm_mmap_params { + struct file *file; + unsigned long addr; + unsigned long len; + unsigned long prot; + unsigned long flag; + unsigned long offset; +}; + +/* + * Arbitrarily chosen user address for the base allocation. + */ +#define UBUF_ADDR_BASE SZ_2M + +/* Create and attach a new mm if it doesn't already exist. */ +static int kunit_attach_mm(void) +{ + struct vm_area_struct *vma; + struct mm_struct *mm; + + if (current->mm) + return 0; + + mm = mm_alloc(); + if (!mm) + return -ENOMEM; + + if (mmap_write_lock_killable(mm)) + goto out_free; + + /* Define the task size. */ + mm->task_size = TASK_SIZE; + + /* Prepare the base VMA. */ + vma = vm_area_alloc(mm); + if (!vma) + goto out_unlock; + + vma_set_anonymous(vma); + vma->vm_start = UBUF_ADDR_BASE; + vma->vm_end = UBUF_ADDR_BASE + PAGE_SIZE; + vm_flags_init(vma, VM_READ | VM_MAYREAD | VM_WRITE | VM_MAYWRITE); + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); + + if (insert_vm_struct(mm, vma)) + goto out_free_vma; + + mmap_write_unlock(mm); + + /* Make sure we can allocate new VMAs. */ + arch_pick_mmap_layout(mm, ¤t->signal->rlim[RLIMIT_STACK]); + + /* Attach the mm. It will be cleaned up when the process dies. */ + kthread_use_mm(mm); + + return 0; + +out_free_vma: + vm_area_free(vma); +out_unlock: + mmap_write_unlock(mm); +out_free: + mmput(mm); + return -ENOMEM; +} + +static int kunit_vm_mmap_init(struct kunit_resource *res, void *context) +{ + struct kunit_vm_mmap_params *p = context; + struct kunit_vm_mmap_resource vres; + int ret; + + ret = kunit_attach_mm(); + if (ret) + return ret; + + vres.size = p->len; + vres.addr = vm_mmap(p->file, p->addr, p->len, p->prot, p->flag, p->offset); + if (!vres.addr) + return -ENOMEM; + res->data = kmemdup(&vres, sizeof(vres), GFP_KERNEL); + if (!res->data) { + vm_munmap(vres.addr, vres.size); + return -ENOMEM; + } + + return 0; +} + +static void kunit_vm_mmap_free(struct kunit_resource *res) +{ + struct kunit_vm_mmap_resource *vres = res->data; + + /* + * Since this is executed from the test monitoring process, + * the test's mm has already been torn down. We don't need + * to run vm_munmap(vres->addr, vres->size), only clean up + * the vres. + */ + + kfree(vres); + res->data = NULL; +} + +unsigned long kunit_vm_mmap(struct kunit *test, struct file *file, + unsigned long addr, unsigned long len, + unsigned long prot, unsigned long flag, + unsigned long offset) +{ + struct kunit_vm_mmap_params params = { + .file = file, + .addr = addr, + .len = len, + .prot = prot, + .flag = flag, + .offset = offset, + }; + struct kunit_vm_mmap_resource *vres; + + vres = kunit_alloc_resource(test, + kunit_vm_mmap_init, + kunit_vm_mmap_free, + GFP_KERNEL, + ¶ms); + if (vres) + return vres->addr; + return 0; +} +EXPORT_SYMBOL_GPL(kunit_vm_mmap); + void kunit_cleanup(struct kunit *test) { struct kunit_resource *res; -- 2.34.1
