From 23e591f485e2e644d92595f999597eec89fdcab7 Mon Sep 17 00:00:00 2001
From: Ed Schouten <ed@FreeBSD.org>
Date: Fri, 9 Sep 2016 07:10:50 +0000
Subject: [PATCH] Properly patch up dirname()/basename() calls to not clobber
 ent->log.

It turns out that we had a couple of more calls to dirname()/basename()
in newsyslog(8) that assume the input isn't clobbered. This is bad,
because it apparently breaks log rotation now that the new dirname()
implementation has been merged.

Fix this by first copying the input and then calling
dirname()/basename(). While there, improve the naming of variables in
this function a bit.

Reported by:	Ryan Steinmetz, gjb
Reviewed by:	bdrewery, allanjude
Differential Revision:	https://reviews.freebsd.org/D7838
---
 usr.sbin/newsyslog/newsyslog.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/usr.sbin/newsyslog/newsyslog.c b/usr.sbin/newsyslog/newsyslog.c
index 766c756e2e7b..90a9fe209a91 100644
--- a/usr.sbin/newsyslog/newsyslog.c
+++ b/usr.sbin/newsyslog/newsyslog.c
@@ -1510,11 +1510,11 @@ validate_old_timelog(int fd, const struct dirent *dp, const char *logfname,
 static void
 delete_oldest_timelog(const struct conf_entry *ent, const char *archive_dir)
 {
-	char *logfname, *s, *dir, errbuf[80];
+	char *basebuf, *dirbuf, errbuf[80];
+	const char *base, *dir;
 	int dir_fd, i, logcnt, max_logcnt;
 	struct oldlog_entry *oldlogs;
 	struct dirent *dp;
-	const char *cdir;
 	struct tm tm;
 	DIR *dirp;
 
@@ -1522,19 +1522,19 @@ delete_oldest_timelog(const struct conf_entry *ent, const char *archive_dir)
 	max_logcnt = MAX_OLDLOGS;
 	logcnt = 0;
 
-	if (archive_dir != NULL && archive_dir[0] != '\0')
-		cdir = archive_dir;
-	else
-		if ((cdir = dirname(ent->log)) == NULL)
-			err(1, "dirname()");
-	if ((dir = strdup(cdir)) == NULL)
-		err(1, "strdup()");
+	if (archive_dir != NULL && archive_dir[0] != '\0') {
+		dirbuf = NULL;
+		dir = archive_dir;
+	} else {
+		if ((dirbuf = strdup(ent->log)) == NULL)
+			err(1, "strdup()");
+		dir = dirname(dirbuf);
+	}
 
-	if ((s = basename(ent->log)) == NULL)
-		err(1, "basename()");
-	if ((logfname = strdup(s)) == NULL)
+	if ((basebuf = strdup(ent->log)) == NULL)
 		err(1, "strdup()");
-	if (strcmp(logfname, "/") == 0)
+	base = basename(basebuf);
+	if (strcmp(base, "/") == 0)
 		errx(1, "Invalid log filename - became '/'");
 
 	if (verbose > 2)
@@ -1545,7 +1545,7 @@ delete_oldest_timelog(const struct conf_entry *ent, const char *archive_dir)
 		err(1, "Cannot open log directory '%s'", dir);
 	dir_fd = dirfd(dirp);
 	while ((dp = readdir(dirp)) != NULL) {
-		if (validate_old_timelog(dir_fd, dp, logfname, &tm) == 0)
+		if (validate_old_timelog(dir_fd, dp, base, &tm) == 0)
 			continue;
 
 		/*
@@ -1610,8 +1610,8 @@ delete_oldest_timelog(const struct conf_entry *ent, const char *archive_dir)
 		free(oldlogs[i].fname);
 	}
 	free(oldlogs);
-	free(logfname);
-	free(dir);
+	free(dirbuf);
+	free(basebuf);
 }
 
 /*