Re: [LTP] [PATCH] syscalls/msgstress01: Fix off by one in array access

Petr Vorel
2024-05-24T11:40:01Z

> Hi!
> > I'd at least add a check that size == data.len + 1.

> Which is not true actually because we always send a 100 bytes of data
> regardless the message size, which is probably another oversight.

> So let's keep the test as it is for now and I will do more work on it
> after the release.

> To fix this we would have to do at least, but I do not want to change
> the test at this point just before the release:

Sounds reasonable, I'll check it. But now I'm going to tag the release.

> diff --git a/testcases/kernel/syscalls/ipc/msgstress/msgstress01.c b/testcases/kernel/syscalls/ipc/msgstress/msgstress01.c
> index b6a64cf4f..f0da595cd 100644
> --- a/testcases/kernel/syscalls/ipc/msgstress/msgstress01.c
> +++ b/testcases/kernel/syscalls/ipc/msgstress/msgstress01.c
> @@ -109,7 +109,7 @@ static void writer(const int id, const int pos)
> int iter = num_iterations;

> while (--iter >= 0 && !(*stop)) {
> - int size = msgsnd(id, &buff->msg, 100, IPC_NOWAIT);
> + int size = msgsnd(id, &buff->msg, buff->msg.data.len + 1, IPC_NOWAIT);

> if (size < 0) {
> if (errno == EAGAIN) {
> @@ -160,6 +160,15 @@ static void reader(const int id, const int pos)
> return;
> }

> + if (msg_recv.data.len + 1 != size) {
> + tst_res(TFAIL,
> + "Wrong message size have %i expected %i",
> + size, msg_recv.data.len+1);
> + *stop = 1;
> + *fail = 1;
> + return;
Very nit: tst_res(TFAIL and *stop and *fail assignments could be in some macro
(e.g. QUIT(msg, ...) ).

Kind regards,
Petr
> + }
> +
> for (int i = 0; i < msg_recv.data.len; i++) {
> if (msg_recv.data.pbytes[i] != buff->msg.data.pbytes[i]) {
> tst_res(TFAIL, "Received wrong data at index %d: %x != %x", i,