On Tue, 11 Jun 2024 at 05:33, Kees Cook <kees@xxxxxxxxxx> wrote: > > 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 <kees@xxxxxxxxxx> > --- Thanks: this looks good to me, at least on the KUnit side of things. Reviewed-by: David Gow <davidgow@xxxxxxxxxx> Cheers, -- David > include/kunit/test.h | 17 +++++++ > lib/kunit/Makefile | 1 + > lib/kunit/user_alloc.c | 111 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 129 insertions(+) > create mode 100644 lib/kunit/user_alloc.c > > diff --git a/include/kunit/test.h b/include/kunit/test.h > index e32b4cb7afa2..ec61cad6b71d 100644 > --- a/include/kunit/test.h > +++ b/include/kunit/test.h > @@ -480,6 +480,23 @@ 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/Makefile b/lib/kunit/Makefile > index 309659a32a78..56dd67dc6e57 100644 > --- a/lib/kunit/Makefile > +++ b/lib/kunit/Makefile > @@ -2,6 +2,7 @@ obj-$(CONFIG_KUNIT) += kunit.o > > kunit-objs += test.o \ > resource.o \ > + user_alloc.o \ > static_stub.o \ > string-stream.o \ > assert.o \ > diff --git a/lib/kunit/user_alloc.c b/lib/kunit/user_alloc.c > new file mode 100644 > index 000000000000..d66f42282f43 > --- /dev/null > +++ b/lib/kunit/user_alloc.c > @@ -0,0 +1,111 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * KUnit userspace memory allocation resource management. > + */ > +#include <kunit/resource.h> > +#include <kunit/test.h> > +#include <linux/kthread.h> > +#include <linux/mm.h> > + > +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; > +}; > + > +/* Create and attach a new mm if it doesn't already exist. */ > +static int kunit_attach_mm(void) > +{ > + struct mm_struct *mm; > + > + if (current->mm) > + return 0; > + > + mm = mm_alloc(); > + if (!mm) > + return -ENOMEM; > + > + /* Define the task size. */ > + mm->task_size = TASK_SIZE; > + > + /* 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; > +} > + > +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); > -- > 2.34.1 >
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