From: Khem Raj <raj.khem@gmail.com>
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 [thread overview]
Message-ID: <20210702202810.2779765-1-raj.khem@gmail.com> (raw)
This avoids crashes in libc when cmsg is null and refrencing msg
structure when it is null
Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
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
--
2.32.0
next reply other threads:[~2021-07-02 20:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-02 20:28 Khem Raj [this message]
2021-07-05 17:51 ` Adhemerval Zanella
2021-07-06 16:22 ` Khem Raj
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