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ntp: check value returned by CMSG_FIRSTHDR

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In NIO_Linux_RequestTxTimestamp(), check the returned pointer and the
length of the buffer before adding the control message. This fixes an
issue reported by the Clang static analyzer.
This commit is contained in:
Miroslav Lichvar 2019-05-09 17:34:53 +02:00
parent 69d3913f3e
commit 64fd1b8ba5
1 changed files with 6 additions and 1 deletions
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7
ntp_io_linux.c
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@ -856,7 +856,12 @@ NIO_Linux_RequestTxTimestamp(struct msghdr *msg, int cmsglen, int sock_fd)
/* Add control message that will enable TX timestamping for this message.
Don't use CMSG_NXTHDR as the one in glibc is buggy for creating new
control messages. */
cmsg = (struct cmsghdr *)((char *)CMSG_FIRSTHDR(msg) + cmsglen);
cmsg = CMSG_FIRSTHDR(msg);
if (!cmsg || cmsglen + CMSG_SPACE(sizeof (ts_tx_flags)) > msg->msg_controllen)
return cmsglen;
cmsg = (struct cmsghdr *)((char *)cmsg + cmsglen);
memset(cmsg, 0, CMSG_SPACE(sizeof (ts_tx_flags)));
cmsglen += CMSG_SPACE(sizeof (ts_tx_flags));