mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-29 22:02:02 +00:00
Code Issues Releases Wiki Activity

selftests/bpf: Test ringbuf mmap read-only and read-write restrictions

Browse source 
Extend ringbuf selftest to validate read/write and read-only restrictions on
memory mapping consumer/producer/data pages. Ensure no "escalations" from
PROT_READ to PROT_WRITE/PROT_EXEC is allowed. And test that mremap() fails to
expand mmap()'ed area.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210514180726.843157-1-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2021-05-14 11:07:26 -07:00 committed by Daniel Borkmann
parent 8f1634b821
commit 704e2beba2
1 changed files with 48 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

49
tools/testing/selftests/bpf/prog_tests/ringbuf.c
View file

@ -86,8 +86,9 @@ void test_ringbuf(void)
const size_t rec_sz = BPF_RINGBUF_HDR_SZ + sizeof(struct sample);
pthread_t thread;
long bg_ret = -1;
int err, cnt;
int err, cnt, rb_fd;
int page_size = getpagesize();
void *mmap_ptr, *tmp_ptr;
skel = test_ringbuf__open();
if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
@ -101,6 +102,52 @@ void test_ringbuf(void)
if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
goto cleanup;
rb_fd = bpf_map__fd(skel->maps.ringbuf);
/* good read/write cons_pos */
mmap_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rb_fd, 0);
ASSERT_OK_PTR(mmap_ptr, "rw_cons_pos");
tmp_ptr = mremap(mmap_ptr, page_size, 2 * page_size, MREMAP_MAYMOVE);
if (!ASSERT_ERR_PTR(tmp_ptr, "rw_extend"))
goto cleanup;
ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_cons_pos_protect");
ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw");
/* bad writeable prod_pos */
mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, page_size);
err = -errno;
ASSERT_ERR_PTR(mmap_ptr, "wr_prod_pos");
ASSERT_EQ(err, -EPERM, "wr_prod_pos_err");
/* bad writeable data pages */
mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
err = -errno;
ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_one");
ASSERT_EQ(err, -EPERM, "wr_data_page_one_err");
mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 3 * page_size);
ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_two");
mmap_ptr = mmap(NULL, 2 * page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_all");
/* good read-only pages */
mmap_ptr = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED, rb_fd, 0);
if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
goto cleanup;
ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_WRITE), "write_protect");
ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_EXEC), "exec_protect");
ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 4 * page_size, MREMAP_MAYMOVE), "ro_remap");
ASSERT_OK(munmap(mmap_ptr, 4 * page_size), "unmap_ro");
/* good read-only pages with initial offset */
mmap_ptr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, rb_fd, page_size);
if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
goto cleanup;
ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_WRITE), "write_protect");
ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_protect");
ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 3 * page_size, MREMAP_MAYMOVE), "ro_remap");
ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_ro");
/* only trigger BPF program for current process */
skel->bss->pid = getpid();