On Sun, Jan 31, 2021 at 5:09 PM KP Singh <kpsingh@xxxxxxxxxx> wrote: > > 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) Funny enough, but I can't repro it locally anymore. I have gcc 10.2.0. But your suggested fix below does look like a correct one, so feel free to send it over, thanks! > > 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(-) > > > > > > > [...]
