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Fri, 02 Jul 2021 13:28:13 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH] linux: Check for null value msghdr struct before use Date: Fri, 2 Jul 2021 13:28:10 -0700 Message-Id: <20210702202810.2779765-1-raj.khem@gmail.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 X-Spam-Status: No, score=-11.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Khem Raj via Libc-alpha From: Khem Raj Reply-To: Khem Raj Errors-To: libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org Sender: "Libc-alpha" This avoids crashes in libc when cmsg is null and refrencing msg structure when it is null Signed-off-by: Khem Raj Reviewed-by: Adhemerval Zanella --- sysdeps/unix/sysv/linux/convert_scm_timestamps.c | 2 ++ sysdeps/unix/sysv/linux/recvmsg.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/sysdeps/unix/sysv/linux/convert_scm_timestamps.c b/sysdeps/unix/sysv/linux/convert_scm_timestamps.c index d75a4618dd6..5af71847f57 100644 --- a/sysdeps/unix/sysv/linux/convert_scm_timestamps.c +++ b/sysdeps/unix/sysv/linux/convert_scm_timestamps.c @@ -87,6 +87,8 @@ __convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize) msg->msg_controllen += CMSG_SPACE (sizeof tvts); cmsg = CMSG_NXTHDR(msg, last); + if (cmsg == NULL) + return; cmsg->cmsg_level = SOL_SOCKET; cmsg->cmsg_type = type; cmsg->cmsg_len = CMSG_LEN (sizeof tvts); diff --git a/sysdeps/unix/sysv/linux/recvmsg.c b/sysdeps/unix/sysv/linux/recvmsg.c index a2a600228ba..19c49e2a85c 100644 --- a/sysdeps/unix/sysv/linux/recvmsg.c +++ b/sysdeps/unix/sysv/linux/recvmsg.c @@ -25,7 +25,7 @@ __libc_recvmsg (int fd, struct msghdr *msg, int flags) { ssize_t r; #ifndef __ASSUME_TIME64_SYSCALLS - socklen_t orig_controllen = msg->msg_controllen; + socklen_t orig_controllen = (msg) ? msg->msg_controllen : 0; #endif #ifdef __ASSUME_RECVMSG_SYSCALL @@ -35,7 +35,7 @@ __libc_recvmsg (int fd, struct msghdr *msg, int flags) #endif #ifndef __ASSUME_TIME64_SYSCALLS - if (r >= 0) + if (r >= 0 && orig_controllen) __convert_scm_timestamps (msg, orig_controllen); #endif