From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_MSPIKE_H2 autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 23528 invoked from network); 27 Feb 2023 19:48:47 -0000 Received: from second.openwall.net (193.110.157.125) by inbox.vuxu.org with ESMTPUTF8; 27 Feb 2023 19:48:47 -0000 Received: (qmail 7603 invoked by uid 550); 27 Feb 2023 19:48:41 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 7564 invoked from network); 27 Feb 2023 19:48:40 -0000 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru C7D4944C1001 From: Alexey Izbyshev To: musl@lists.openwall.com Date: Mon, 27 Feb 2023 22:46:54 +0300 Message-Id: <20230227194654.61114-1-izbyshev@ispras.ru> X-Mailer: git-send-email 2.39.1 MIME-Version: 1.0 Mail-Followup-To: musl@lists.openwall.com Content-Transfer-Encoding: 8bit Subject: [musl] [PATCH] accept4: don't fall back to accept if we got unknown flags accept4 emulation via accept ignores unknown flags, so it can spuriously succeed instead of failing (or succeed without doing the action implied by an unknown flag if it's added in a future kernel). Worse, unknown flags trigger the fallback code even on modern kernels if the real accept4 syscall returns EINVAL, because this is indistinguishable from socketcall returning EINVAL due to lack of accept4 support. Fix this by always propagating the syscall attempt failure if unknown flags are present. The behavior is still not ideal on old kernels lacking accept4 on arches with socketcall, where failing with ENOSYS instead of EINVAL returned by socketcall would be preferable, but at least modern kernels are now fine. --- src/network/accept4.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/network/accept4.c b/src/network/accept4.c index 59ab1726..bbb79507 100644 --- a/src/network/accept4.c +++ b/src/network/accept4.c @@ -9,6 +9,7 @@ int accept4(int fd, struct sockaddr *restrict addr, socklen_t *restrict len, int if (!flg) return accept(fd, addr, len); int ret = socketcall_cp(accept4, fd, addr, len, flg, 0, 0); if (ret>=0 || (errno != ENOSYS && errno != EINVAL)) return ret; + if (flg & ~(SOCK_CLOEXEC|SOCK_NONBLOCK)) return ret; ret = accept(fd, addr, len); if (ret<0) return ret; if (flg & SOCK_CLOEXEC) -- 2.39.1