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/[email protected]/ [1]
Co-developed-by: Mark Rutland <[email protected]>
Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
---
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
On Tue, 11 Jun 2024 at 05:33, Kees Cook <[email protected]> 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/[email protected]/ [1]
> Co-developed-by: Mark Rutland <[email protected]>
> Signed-off-by: Mark Rutland <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
> ---
Thanks: this looks good to me, at least on the KUnit side of things.
Reviewed-by: David Gow <[email protected]>
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
>