added new config directive $omfileForceChown to fix some broken system configs.

See ticket for details: http://bugzilla.adiscon.com/show_bug.cgi?id=150
author: Rainer Gerhards <rgerhards@adiscon.com> 2009-09-11 11:23:47 +0200
committer: Rainer Gerhards <rgerhards@adiscon.com> 2009-09-11 11:23:47 +0200
commit: bfac3c68f47b8769b0936fb80eeea8880793fd2d (patch)
tree: 550db4420b2421c1e01b900efbd832fe99b39989
parent: b34a23c6523de492e02f064a73a93abcea670667 (diff)
download: rsyslog-bfac3c68f47b8769b0936fb80eeea8880793fd2d.tar.gz
rsyslog-bfac3c68f47b8769b0936fb80eeea8880793fd2d.tar.xz
rsyslog-bfac3c68f47b8769b0936fb80eeea8880793fd2d.zip
4 files changed, 93 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index 5b30621b..7ae02fd8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,9 @@ Version 4.7.0  [v4-devel] (rgerhards), 2009-09-??
 - added $LogRSyslogStatusMessages configuration directive
   permitting to turn off rsyslog start/stop/HUP messages. See Debian
   ticket http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=463793
+- added new config directive $omfileForceChown to (try to) fix some broken
+  system configs.
+  See ticket for details: http://bugzilla.adiscon.com/show_bug.cgi?id=150
 ---------------------------------------------------------------------------
 Version 4.5.3  [v4-beta] (rgerhards), 2009-08-??
 - bugfix: repeated messages were incorrectly processed
diff --git a/doc/rsconf1_omfileforcechown.html b/doc/rsconf1_omfileforcechown.html
new file mode 100644
index 00000000..7415a6f6
--- /dev/null
+++ b/doc/rsconf1_omfileforcechown.html
@@ -0,0 +1,64 @@
+<html>
+<head>
+<title>rsyslog.conf file</title>
+</head>
+<body>
+<a href="rsyslog_conf_global.html">back</a>
+
+<h2>$omfileForceChown</h2>
+<p><b>Type:</b> global configuration directive</p>
+<p><b>Parameter Values:</b> boolean (on/off, yes/no)</p>
+<p><b>Available since:</b> 4.7.0+, 5.3.0+</p>
+<p><b>Default:</b> off</p>
+<p><b>Description:</b></p>
+<p>Forces rsyslogd to change the ownership for output files that already exist. Please note
+that this tries to fix a potential problem that exists outside the scope of rsyslog. Actually,
+it tries to fix invalid ownership/permission settings set by the original file creator.
+<p>Rsyslog changes the ownership during initial execution with root privileges. When a privelege
+drop is configured, privileges are dropped after the file owner ship is changed. Not that this currently
+is a limitation in rsyslog's privilege drop code, which is on the TODO list to be removed. See Caveats
+section below for the important implications.
+<p><b>Caveats:</b></p>
+<p>This directive tries to fix a problem that actually is outside the scope of rsyslog. As such,
+there are a couple of restrictions and situations in which it will not work. <b>Users are strongly
+encouraged to fix their system instead of turning this directive on</b> - it should only be used
+as a last resort.
+<p>At least in the following scenario, this directive will fail expectedly:
+<p>It does not address
+the situation that someone changes the ownership *after* rsyslogd has started.
+Let's, for example, consider a log rotation script.
+<ul>
+<li>rsyslog is started
+<li>ownership is changed
+<li>privileges dropped
+<li>log rotation (lr) script starts
+<li>lr removes files
+<li>lr creates new files with root:adm (or whatever else)
+<li>lr HUPs rsyslogd
+<li>rsyslogd closes files
+<li>rsyslogd tries to open files
+<li>rsyslogd tries to change ownership --&gt; fail as we are non-root now
+<li>file open fails
+</ul>
+
+Please note that once the privilege drop code is refactored, this directive will
+no longer work, because then privileges will be dropped before any action is performed,
+and thus we will no longer be able to chown files that do not belong to the
+user rsyslogd is configured to run under.
+
+<p>So <b>expect the directive to go away</b>. It will not
+be removed in version 4, but may disappear at any time for any version greater than 4.
+
+<p><b>Sample:</b></p>
+<p><code><b>$FileOwner loguser</b>
+<br><b>$omfileForceChown on</b></code></p>
+
+<p>[<a href="rsyslog_conf.html">rsyslog.conf overview</a>] [<a href="manual.html">manual 
+index</a>] [<a href="http://www.rsyslog.com/">rsyslog site</a>]</p>
+<p><font size="2">This documentation is part of the
+<a href="http://www.rsyslog.com/">rsyslog</a> project.<br>
+Copyright &copy; 2007 by <a href="http://www.gerhards.net/rainer">Rainer Gerhards</a> and
+<a href="http://www.adiscon.com/">Adiscon</a>. Released under the GNU GPL 
+version 2 or higher.</font></p>
+</body>
+</html>
diff --git a/doc/rsyslog_conf_global.html b/doc/rsyslog_conf_global.html
index 74255c54..5f80f92e 100644
--- a/doc/rsyslog_conf_global.html
+++ b/doc/rsyslog_conf_global.html
@@ -225,6 +225,7 @@ error recovery thus can handle write errors without data loss. Note that this op
 severely reduces the effect of zip compression and should be switched to off
 for that use case. Note that the default -off- is primarily an aid to preserve
 the traditional syslogd behaviour.</li>
+<li><a href="rsconf1_omfileforcechown.html">$omfileForceChown</a> - force ownership change for all files</li>
 <li><b>$RepeatedMsgContainsOriginalMsg</b> [on/<b>off</b>] - "last message repeated n times" messages, if generated,
 have a different format that contains the message that is being repeated.
 Note that only the first "n" characters are included, with n to be at least 80 characters, most
diff --git a/tools/omfile.c b/tools/omfile.c
index bb12b4b6..eaffa70e 100644
--- a/tools/omfile.c
+++ b/tools/omfile.c
@@ -88,11 +88,13 @@ typedef struct s_dynaFileCacheEntry dynaFileCacheEntry;
 #define IOBUF_DFLT_SIZE 1024	/* default size for io buffers */
 #define FLUSH_INTRVL_DFLT 1 	/* default buffer flush interval (in seconds) */
 
+#define DFLT_bForceChown 0
 /* globals for default values */
 static int iDynaFileCacheSize = 10; /* max cache for dynamic files */
 static int fCreateMode = 0644; /* mode to use when creating files */
 static int fDirCreateMode = 0700; /* mode to use when creating files */
 static int	bFailOnChown;	/* fail if chown fails? */
+static int	bForceChown = DFLT_bForceChown;	/* Force chown() on existing files? */
 static uid_t	fileUID;	/* UID to be used for newly created files */
 static uid_t	fileGID;	/* GID to be used for newly created files */
 static uid_t	dirUID;		/* UID to be used for newly created directories */
@@ -115,6 +117,7 @@ typedef struct _instanceData {
 	int	fDirCreateMode;	/* creation mode for mkdir() */
 	int	bCreateDirs;	/* auto-create directories? */
 	int	bSyncFile;	/* should the file by sync()'ed? 1- yes, 0- no */
+	bool	bForceChown;	/* force chown() on existing files? */
 	uid_t	fileUID;	/* IDs for creation */
 	uid_t	dirUID;
 	gid_t	fileGID;
@@ -152,12 +155,14 @@ CODESTARTdbgPrintInstInfo
 		       "\tcreate directories: %s\n"
 		       "\tfile owner %d, group %d\n"
 		       "\tdirectory owner %d, group %d\n"
+		       "\tforce chown() for all files: %s\n"
 		       "\tfail if owner/group can not be set: %s\n",
 		        pData->f_fname,
 			pData->iDynaFileCacheSize,
 			pData->bCreateDirs ? "yes" : "no",
 			pData->fileUID, pData->fileGID,
 			pData->dirUID, pData->dirGID,
+			pData->bForceChown ? "yes" : "no",
 			pData->bFailOnChown ? "yes" : "no"
 			);
 	} else { /* regular file */
@@ -346,7 +351,22 @@ prepareFile(instanceData *pData, uchar *newFileName)
 	int fd;
 	DEFiRet;
 
-	if(access((char*)newFileName, F_OK) != 0) {
+	if(access((char*)newFileName, F_OK) == 0) {
+		if(pData->bForceChown) {
+			/* Try to fix wrong ownership set by someone else. Note that this code
+			 * will no longer work once we have made the $PrivDrop code fully secure.
+			 * This change is based on an idea of Michael Terry, provided as part of
+			 * the effort to make rsyslogd the Ubuntu default syslogd.
+			 * rgerhards, 2009-09-11
+			 */
+			if(chown((char*)newFileName, pData->fileUID, pData->fileGID) != 0) {
+				if(pData->bFailOnChown) {
+					int eSave = errno;
+					errno = eSave;
+				}
+			}
+		}
+	} else {
 		/* file does not exist, create it (and eventually parent directories */
 		fd = -1;
 		if(pData->bCreateDirs) {
@@ -367,7 +387,7 @@ prepareFile(instanceData *pData, uchar *newFileName)
 				pData->fCreateMode);
 		if(fd != -1) {
 			/* check and set uid/gid */
-			if(pData->fileUID != (uid_t)-1 || pData->fileGID != (gid_t) -1) {
+			if(pData->bForceChown || pData->fileUID != (uid_t)-1 || pData->fileGID != (gid_t) -1) {
 				/* we need to set owner/group */
 				if(fchown(fd, pData->fileUID, pData->fileGID) != 0) {
 					if(pData->bFailOnChown) {
@@ -678,6 +698,7 @@ CODESTARTparseSelectorAct
 	pData->fDirCreateMode = fDirCreateMode;
 	pData->bCreateDirs = bCreateDirs;
 	pData->bFailOnChown = bFailOnChown;
+	pData->bForceChown = bForceChown;
 	pData->fileUID = fileUID;
 	pData->fileGID = fileGID;
 	pData->dirUID = dirUID;
@@ -712,6 +733,7 @@ static rsRetVal resetConfigVariables(uchar __attribute__((unused)) *pp, void __a
 	dirUID = -1;
 	dirGID = -1;
 	bFailOnChown = 1;
+	bForceChown = DFLT_bForceChown;
 	iDynaFileCacheSize = 10;
 	fCreateMode = 0644;
 	fDirCreateMode = 0700;
@@ -778,6 +800,7 @@ CODEmodInit_QueryRegCFSLineHdlr
 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"filecreatemode", 0, eCmdHdlrFileCreateMode, NULL, &fCreateMode, STD_LOADABLE_MODULE_ID));
 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"createdirs", 0, eCmdHdlrBinary, NULL, &bCreateDirs, STD_LOADABLE_MODULE_ID));
 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"failonchownfailure", 0, eCmdHdlrBinary, NULL, &bFailOnChown, STD_LOADABLE_MODULE_ID));
+	CHKiRet(omsdRegCFSLineHdlr((uchar *)"omfileForceChown", 0, eCmdHdlrBinary, NULL, &bForceChown, STD_LOADABLE_MODULE_ID));
 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"actionfileenablesync", 0, eCmdHdlrBinary, NULL, &bEnableSync, STD_LOADABLE_MODULE_ID));
 	CHKiRet(regCfSysLineHdlr((uchar *)"actionfiledefaulttemplate", 0, eCmdHdlrGetWord, NULL, &pszTplName, NULL));
 	CHKiRet(omsdRegCFSLineHdlr((uchar *)"resetconfigvariables", 1, eCmdHdlrCustomHandler, resetConfigVariables, NULL, STD_LOADABLE_MODULE_ID));
author	Rainer Gerhards <rgerhards@adiscon.com>	2009-09-11 11:23:47 +0200
committer	Rainer Gerhards <rgerhards@adiscon.com>	2009-09-11 11:23:47 +0200
commit	bfac3c68f47b8769b0936fb80eeea8880793fd2d (patch)
tree	550db4420b2421c1e01b900efbd832fe99b39989
parent	b34a23c6523de492e02f064a73a93abcea670667 (diff)
download	rsyslog-bfac3c68f47b8769b0936fb80eeea8880793fd2d.tar.gz rsyslog-bfac3c68f47b8769b0936fb80eeea8880793fd2d.tar.xz rsyslog-bfac3c68f47b8769b0936fb80eeea8880793fd2d.zip