Re: [PATCH v7 4/4] selftests/liveupdate: add test cases for LIVEUPDATE_SESSION_GET_NAME

[Luca Boccassi <luca.boccassi@gmail.com>]

On Sat, 18 Apr 2026 at 16:50, Pasha Tatashin <pasha.tatashin@soleen.com> wrote:
>
> On 04-18 15:09, luca.boccassi@gmail.com wrote:
> > From: Luca Boccassi <luca.boccassi@gmail.com>
> >
> > Verify that the new LIVEUPDATE_SESSION_GET_NAME ioctl works
> > as expected via new test cases in the existing liveupdate selftest.
> >
> > Signed-off-by: Luca Boccassi <luca.boccassi@gmail.com>
> > ---
> > v5: merge with LUO_SESSION_MAGIC series as they both change the same
> >     unit test file, to avoid merge conflicts
> >     split into separate patch
> > v6: add more test cases as suggested
> >     more verbose commit message
> >
> >  .../testing/selftests/liveupdate/liveupdate.c | 138 ++++++++++++++++++
> >  1 file changed, 138 insertions(+)
> >
> > diff --git a/tools/testing/selftests/liveupdate/liveupdate.c b/tools/testing/selftests/liveupdate/liveupdate.c
> > index d132b4685f76..ffbcbd465c9b 100644
> > --- a/tools/testing/selftests/liveupdate/liveupdate.c
> > +++ b/tools/testing/selftests/liveupdate/liveupdate.c
> > @@ -105,6 +105,22 @@ static int create_session(int lu_fd, const char *name)
> >       return args.fd;
> >  }
> >
> > +/* Helper function to get a session name via ioctl. */
> > +static int get_session_name(int session_fd, char *name, size_t name_len)
> > +{
> > +     struct liveupdate_session_get_name args = {};
> > +
> > +     args.size = sizeof(args);
> > +
> > +     if (ioctl(session_fd, LIVEUPDATE_SESSION_GET_NAME, &args))
> > +             return -errno;
> > +
> > +     strncpy(name, (char *)args.name, name_len - 1);
> > +     name[name_len - 1] = '\0';
> > +
> > +     return 0;
> > +}
> > +
> >  /*
> >   * Test Case: Create Duplicate Session
> >   *
> > @@ -385,4 +401,126 @@ TEST_F(liveupdate_device, session_fstat)
> >       ASSERT_EQ(close(session_fd2), 0);
> >  }
> >
> > +/*
> > + * Test Case: Get Session Name
> > + *
> > + * Verifies that the full session name can be retrieved from a session file
> > + * descriptor via ioctl.
> > + */
> > +TEST_F(liveupdate_device, get_session_name)
> > +{
> > +     char name_buf[LIVEUPDATE_SESSION_NAME_LENGTH] = {};
> > +     const char *session_name = "get-name-test-session";
> > +     int session_fd;
> > +
> > +     self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
> > +     if (self->fd1 < 0 && errno == ENOENT)
> > +             SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
> > +     ASSERT_GE(self->fd1, 0);
> > +
> > +     session_fd = create_session(self->fd1, session_name);
> > +     ASSERT_GE(session_fd, 0);
> > +
> > +     ASSERT_EQ(get_session_name(session_fd, name_buf, sizeof(name_buf)), 0);
> > +     ASSERT_STREQ(name_buf, session_name);
> > +
> > +     ASSERT_EQ(close(session_fd), 0);
> > +}
> > +
> > +/*
> > + * Test Case: Get Session Name at Maximum Length
> > + *
> > + * Verifies that a session name using the full LIVEUPDATE_SESSION_NAME_LENGTH
> > + * (minus the null terminator) can be correctly retrieved.
> > + */
> > +TEST_F(liveupdate_device, get_session_name_max_length)
> > +{
> > +     char name_buf[LIVEUPDATE_SESSION_NAME_LENGTH] = {};
> > +     char long_name[LIVEUPDATE_SESSION_NAME_LENGTH];
> > +     int session_fd;
> > +
> > +     memset(long_name, 'A', sizeof(long_name) - 1);
> > +     long_name[sizeof(long_name) - 1] = '\0';
> > +
> > +     self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
> > +     if (self->fd1 < 0 && errno == ENOENT)
> > +             SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
> > +     ASSERT_GE(self->fd1, 0);
> > +
> > +     session_fd = create_session(self->fd1, long_name);
> > +     ASSERT_GE(session_fd, 0);
> > +
> > +     ASSERT_EQ(get_session_name(session_fd, name_buf, sizeof(name_buf)), 0);
> > +     ASSERT_STREQ(name_buf, long_name);
> > +
> > +     ASSERT_EQ(close(session_fd), 0);
> > +}
> > +
> > +/*
> > + * Test Case: Create Session with No Null Termination
> > + *
> > + * Verifies that filling the entire 64-byte name field with non-null characters
> > + * (no '\0' terminator) is handled safely by the kernel. The kernel's strscpy
> > + * truncates to 63 characters, which we verify via get_session_name.
>
> [...]
>
> > + */
> > +TEST_F(liveupdate_device, create_session_no_null_termination)
> > +{
> > +     struct liveupdate_ioctl_create_session args = {};
> > +     char expected_name[LIVEUPDATE_SESSION_NAME_LENGTH];
> > +     char name_buf[LIVEUPDATE_SESSION_NAME_LENGTH] = {};
> > +     int session_fd;
> > +
> > +     self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
> > +     if (self->fd1 < 0 && errno == ENOENT)
> > +             SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
> > +     ASSERT_GE(self->fd1, 0);
> > +
> > +     /* Fill entire name field with 'X', no null terminator */
> > +     args.size = sizeof(args);
> > +     memset(args.name, 'X', sizeof(args.name));
> > +
> > +     ASSERT_EQ(ioctl(self->fd1, LIVEUPDATE_IOCTL_CREATE_SESSION, &args), 0);
> > +     session_fd = args.fd;
> > +     ASSERT_GE(session_fd, 0);
> > +
> > +     /* Kernel should have truncated to 63 chars + '\0' */
> > +     memset(expected_name, 'X', sizeof(expected_name) - 1);
> > +     expected_name[sizeof(expected_name) - 1] = '\0';
> > +
> > +     ASSERT_EQ(get_session_name(session_fd, name_buf, sizeof(name_buf)), 0);
> > +     ASSERT_STREQ(name_buf, expected_name);
> > +
> > +     ASSERT_EQ(close(session_fd), 0);
> > +}
> > +
> > +/*
> > + * Test Case: Create Session with Empty Name
> > + *
> > + * Verifies that creating a session with an empty string name succeeds,
> > + * and that creating a second session with the same empty name fails
> > + * with EEXIST.
> > + */
>
> For the two cases mentioned above, we should implement a fix in the
> kernel:
>
> In luo_session_create(), we should verify that the name is at least 1
> character long and at most LIVEUPDATE_SESSION_NAME_LENGTH - 1.
>
> size_t len = strnlen(name, LIVEUPDATE_SESSION_NAME_LENGTH);
>
> if (!len || len > LIVEUPDATE_SESSION_NAME_LENGTH - 1)
>    return -EINVAL;
>
> This change should be submitted as a separate patch in your series.
>
> Additionally, please include a cover letter in the next version
> explaining the overall series. Once the cover letter is included, you
> can remove the individual patch versions from the stat areas.
>
> Pasha

Ok, all done in v8, thanks