On Thu, Jan 28, 2021 at 2:46 AM Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote: > > On Mon, Jan 11, 2021 at 11:55 PM KP Singh <kpsingh@xxxxxxxxxx> wrote: > > > > It was found in [1] that bpf_inode_storage_get helper did not check > > the nullness of the passed owner ptr which caused an oops when > > dereferenced. This change incorporates the example suggested in [1] into > > the local storage selftest. > > > > The test is updated to create a temporary directory instead of just > > using a tempfile. In order to replicate the issue this copied rm binary > > is renamed tiggering the inode_rename with a null pointer for the > > new_inode. The logic to verify the setting and deletion of the inode > > local storage of the old inode is also moved to this LSM hook. > > > > The change also removes the copy_rm function and simply shells out > > to copy files and recursively delete directories and consolidates the > > logic of setting the initial inode storage to the bprm_committed_creds > > hook and removes the file_open hook. > > > > [1]: https://lore.kernel.org/bpf/CANaYP3HWkH91SN=wTNO9FL_2ztHfqcXKX38SSE-JJ2voh+vssw@xxxxxxxxxxxxxx > > > > Suggested-by: Gilad Reti <gilad.reti@xxxxxxxxx> > > Acked-by: Yonghong Song <yhs@xxxxxx> > > Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx> > > --- > > Hi KP, > > I'm getting a compilation warning when building selftests. Can you > please take a look and send a fix? Thanks! > > /data/users/andriin/linux/tools/testing/selftests/bpf/prog_tests/test_local_storage.c: > In function ‘test_test_local_storage’: > /data/users/andriin/linux/tools/testing/selftests/bpf/prog_tests/test_local_storage.c:143:52: > warning: ‘/copy_of_rm’ directive output may be truncated writing 11 > bytes into a region of size between 1 and 64 [-Wformat-truncation=] > 143 | snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm", > | ^~~~~~~~~~~ > /data/users/andriin/linux/tools/testing/selftests/bpf/prog_tests/test_local_storage.c:143:2: > note: ‘snprintf’ output between 12 and 75 bytes into a destination of > size 64 > 143 | snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm", > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 144 | tmp_dir_path); > | ~~~~~~~~~~~~~ > I don't seem to get this warning, so maybe we are using different compilers. Mine is gcc 10.2.1 20201224 (from debian) That said, I understand why it's complaining, it's for something that cannot really happen: tmp_dir_path cannot be 64 because we actually know its length so the tmp_exec_path cannot really overflow 64 bytes. Can you check if the following patch makes it go away? diff --git a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c index 3bfcf00c0a67..d2c16eaae367 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c +++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c @@ -113,7 +113,7 @@ static bool check_syscall_operations(int map_fd, int obj_fd) void test_test_local_storage(void) { - char tmp_dir_path[64] = "/tmp/local_storageXXXXXX"; + char tmp_dir_path[] = "/tmp/local_storageXXXXXX"; int err, serv_sk = -1, task_fd = -1, rm_fd = -1; struct local_storage *skel = NULL; char tmp_exec_path[64]; If so, I can send you a fix. - KP > > > .../bpf/prog_tests/test_local_storage.c | 96 +++++-------------- > > .../selftests/bpf/progs/local_storage.c | 62 ++++++------ > > 2 files changed, 61 insertions(+), 97 deletions(-) > > > > [...]
