git: 943c446629e3 - main - Revert "libc: Some enhancements to syslog(3)"

The branch main has been updated by asomers:

URL: https://cgit.FreeBSD.org/src/commit/?id=943c446629e33739d3f72795069a5c944e8f329e

commit 943c446629e33739d3f72795069a5c944e8f329e
Author:     Alan Somers <asomers@FreeBSD.org>
AuthorDate: 2021-11-30 17:06:25 +0000
Commit:     Alan Somers <asomers@FreeBSD.org>
CommitDate: 2021-11-30 18:11:43 +0000

    Revert "libc: Some enhancements to syslog(3)"
    
    This reverts commit 2886c93d1bca231260ebc01d4205743ca781f3c7.
    The original commit has two problems:
    
    * It sets SO_SNDBUF to be as large as MAXLINE.  But for unix domain
      sockets, the send buffer is bypassed.  Packets go directly to the
      peer's receive buffer, so setting and querying SO_SNDBUF is
      ineffective.  To ensure that the socket can accept messages of a
      certain size, it would be necessary to add a SO_PEERRCVBUF socket
      option that could query the connected peer's receive buffer size.
    
    * It sets MAXLINE to 8 kB, which is larger than the default sockbuf size
      of 4 kB.  That's ok for the builtin syslogd, which sets its recvbuf
      to 80 kB, but not ok for alternative sysloggers, like rsyslogd, which
      use the default size.
    
    As a consequence, writing messages of more than 4 kB with syslog() as a
    non-root user while running rsyslogd would cause the logging application
    to spin indefinitely within syslog().
    
    PR:             260126
    MFC:            2 weeks
    Sponsored by:   Axcient
    Reviewed by:    markj
    Differential Revision: https://reviews.freebsd.org/D33199
---
 lib/libc/gen/syslog.c | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/lib/libc/gen/syslog.c b/lib/libc/gen/syslog.c
index 797c7389d1a2..19d44db0075a 100644
--- a/lib/libc/gen/syslog.c
+++ b/lib/libc/gen/syslog.c
@@ -57,9 +57,6 @@ __FBSDID("$FreeBSD$");
 
 #include "libc_private.h"
 
-/* Maximum number of characters of syslog message */
-#define	MAXLINE		8192
-
 static int	LogFile = -1;		/* fd for log */
 static int	status;			/* connection status */
 static int	opened;			/* have done openlog() */
@@ -144,7 +141,7 @@ vsyslog1(int pri, const char *fmt, va_list ap)
 	char ch, *p;
 	long tz_offset;
 	int cnt, fd, saved_errno;
-	char hostname[MAXHOSTNAMELEN], *stdp, tbuf[MAXLINE], fmt_cpy[MAXLINE],
+	char hostname[MAXHOSTNAMELEN], *stdp, tbuf[2048], fmt_cpy[1024],
 	    errstr[64], tz_sign;
 	FILE *fp, *fmt_fp;
 	struct bufcookie tbuf_cookie;
@@ -399,19 +396,9 @@ connectlog(void)
 	struct sockaddr_un SyslogAddr;	/* AF_UNIX address of local logger */
 
 	if (LogFile == -1) {
-		socklen_t len;
-
 		if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC,
 		    0)) == -1)
 			return;
-		if (_getsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, &len,
-		    &(socklen_t){sizeof(len)}) == 0) {
-			if (len < MAXLINE) {
-				len = MAXLINE;
-				(void)_setsockopt(LogFile, SOL_SOCKET, SO_SNDBUF,
-				    &len, sizeof(len));
-			}
-		}
 	}
 	if (LogFile != -1 && status == NOCONN) {
 		SyslogAddr.sun_len = sizeof(SyslogAddr);