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authorAndrii Nakryiko <andrii@kernel.org>2021-05-14 11:07:26 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2021-05-20 23:48:38 +0200
commit704e2beba23c45eaa056b1c03b5e1fb221e03f80 (patch)
treeea97b769abc7cc1c79e625421809834528689e47 /tools
parent8f1634b82189e715b0f82f16ce54fab43cfedd8a (diff)
downloadlinux-704e2beba23c45eaa056b1c03b5e1fb221e03f80.tar.bz2
selftests/bpf: Test ringbuf mmap read-only and read-write restrictions
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
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/bpf/prog_tests/ringbuf.c49
1 files changed, 48 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
index de78617f6550..f9a8ae331963 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -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();