r656: Make widelinks use realpath(). Tidy up cases where we need to become a service.

Jeremy.
(This used to be commit a03b6a05e02ec8415efc0e8ceade102e06f8fffe)

6 files changed, 119 insertions, 148 deletions

diff --git a/source3/configure.in b/source3/configure.in
index f4383ea337..7d6cfee111 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -2277,7 +2277,21 @@ if test x"$samba_cv_BROKEN_NISPLUS_INCLUDE_FILES" = x"yes"; then
 	AC_DEFINE(BROKEN_NISPLUS_INCLUDE_FILES,1,[Whether the nisplus include files are broken])
 fi
 
+AC_CACHE_CHECK([if the realpath function allows a NULL argument],samba_cv_REALPATH_TAKES_NULL,[
+AC_TRY_RUN([
+#include <stdio.h>
+#include <limits.h>
+main() {
+	char *newpath = realpath("/tmp", NULL);
+	exit ((newpath != NULL) ? 0 : 1);
+}
+],
+samba_cv_REALPATH_TAKES_NULL=yes,samba_cv_REALPATH_TAKES_NULL=no,samba_cv_REALPATH_TAKES_NULL=cross)])
+if test x"$samba_cv_REALPATH_TAKES_NULL" = x"yes"; then
+    AC_DEFINE(REALPATH_TAKES_NULL,1,[Whether the realpath function allows NULL])
+fi
 
+A
 #################################################
 # check for smbwrapper support
 AC_MSG_CHECKING(whether to use smbwrapper)
diff --git a/source3/smbd/conn.c b/source3/smbd/conn.c
index 9bac0acdb9..e083e14426 100644
--- a/source3/smbd/conn.c
+++ b/source3/smbd/conn.c
@@ -161,6 +161,7 @@ void conn_close_all(void)
 	connection_struct *conn, *next;
 	for (conn=Connections;conn;conn=next) {
 		next=conn->next;
+		set_current_service(conn, True);
 		close_cnum(conn, conn->vuid);
 	}
 }
diff --git a/source3/smbd/filename.c b/source3/smbd/filename.c
index 692c7f7610..a7223e7527 100644
--- a/source3/smbd/filename.c
+++ b/source3/smbd/filename.c
@@ -399,7 +399,7 @@ BOOL check_name(pstring name,connection_struct *conn)
 	}
 
 	if (!lp_widelinks(SNUM(conn))) {
-		ret = reduce_name(conn,name,conn->connectpath);
+		ret = reduce_name(conn,name);
 	}
 
 	/* Check if we are allowing users to follow symlinks */
diff --git a/source3/smbd/process.c b/source3/smbd/process.c
index 966bb63c1e..d0dfc6dd7d 100644
--- a/source3/smbd/process.c
+++ b/source3/smbd/process.c
@@ -344,6 +344,7 @@ force write permissions on print services.
 #define CAN_IPC (1<<3)
 #define AS_GUEST (1<<5)
 #define QUEUE_IN_OPLOCK (1<<6)
+#define DO_CHDIR (1<<7)
 
 /* 
    define a list of possible SMB messages and their corresponding
@@ -373,7 +374,7 @@ static const struct smb_message_struct {
 /* 0x0e */ { "SMBctemp",reply_ctemp,AS_USER | QUEUE_IN_OPLOCK },
 /* 0x0f */ { "SMBmknew",reply_mknew,AS_USER}, 
 /* 0x10 */ { "SMBchkpth",reply_chkpth,AS_USER},
-/* 0x11 */ { "SMBexit",reply_exit,0},
+/* 0x11 */ { "SMBexit",reply_exit,DO_CHDIR},
 /* 0x12 */ { "SMBlseek",reply_lseek,AS_USER},
 /* 0x13 */ { "SMBlockread",reply_lockread,AS_USER},
 /* 0x14 */ { "SMBwriteunlock",reply_writeunlock,AS_USER},
@@ -469,7 +470,7 @@ static const struct smb_message_struct {
 /* 0x6e */ { NULL, NULL, 0 },
 /* 0x6f */ { NULL, NULL, 0 },
 /* 0x70 */ { "SMBtcon",reply_tcon,0},
-/* 0x71 */ { "SMBtdis",reply_tdis,0},
+/* 0x71 */ { "SMBtdis",reply_tdis,DO_CHDIR},
 /* 0x72 */ { "SMBnegprot",reply_negprot,0},
 /* 0x73 */ { "SMBsesssetupX",reply_sesssetup_and_X,0},
 /* 0x74 */ { "SMBulogoffX", reply_ulogoffX, 0}, /* ulogoff doesn't give a valid TID */
@@ -754,7 +755,7 @@ static int switch_message(int type,char *inbuf,char *outbuf,int size,int bufsize
 			return(ERROR_DOS(ERRSRV,ERRaccess));	    
 
 		/* load service specific parameters */
-		if (conn && !set_current_service(conn,(flags & AS_USER)?True:False))
+		if (conn && !set_current_service(conn,(flags & (AS_USER|DO_CHDIR)?True:False)))
 			return(ERROR_DOS(ERRSRV,ERRaccess));
 
 		/* does this protocol need to be run as guest? */
diff --git a/source3/smbd/service.c b/source3/smbd/service.c
index 93b017e94c..04cade9577 100644
--- a/source3/smbd/service.c
+++ b/source3/smbd/service.c
@@ -788,6 +788,9 @@ void close_cnum(connection_struct *conn, uint16 vuid)
 {
 	DirCacheFlush(SNUM(conn));
 
+	file_close_conn(conn);
+	dptr_closecnum(conn);
+
 	change_to_root_user();
 
 	DEBUG(IS_IPC(conn)?3:1, ("%s (%s) closed connection to service %s\n",
@@ -799,9 +802,6 @@ void close_cnum(connection_struct *conn, uint16 vuid)
 
 	yield_connection(conn, lp_servicename(SNUM(conn)));
 
-	file_close_conn(conn);
-	dptr_closecnum(conn);
-
 	/* make sure we leave the directory available for unmount */
 	vfs_ChDir(conn, "/");
 
diff --git a/source3/smbd/vfs.c b/source3/smbd/vfs.c
index 533220e7df..0f3d591ebb 100644
--- a/source3/smbd/vfs.c
+++ b/source3/smbd/vfs.c
@@ -784,168 +784,123 @@ char *vfs_GetWd(connection_struct *conn, char *path)
 	return (path);
 }
 
-
-/* check if the file 'nmae' is a symlink, in that case check that it point to
-   a file that reside under the 'dir' tree */
-
-static BOOL readlink_check(connection_struct *conn, const char *dir, char *name)
-{
-	BOOL ret = True;
-	pstring flink;
-	pstring cleanlink;
-	pstring savedir;
-	pstring realdir;
-	size_t reallen;
-
-	if (!vfs_GetWd(conn, savedir)) {
-		DEBUG(0,("couldn't vfs_GetWd for %s %s\n", name, dir));
-		return False;
-	}
-
-	if (vfs_ChDir(conn, dir) != 0) {
-		DEBUG(0,("couldn't vfs_ChDir to %s\n", dir));
-		return False;
-	}
-
-	if (!vfs_GetWd(conn, realdir)) {
-		DEBUG(0,("couldn't vfs_GetWd for %s\n", dir));
-		vfs_ChDir(conn, savedir);
-		return(False);
-	}
-	
-	reallen = strlen(realdir);
-	if (realdir[reallen -1] == '/') {
-		reallen--;
-		realdir[reallen] = 0;
-	}
-
-	if (SMB_VFS_READLINK(conn, name, flink, sizeof(pstring) -1) != -1) {
-		DEBUG(3,("readlink_check: file path name %s is a symlink\nChecking it's path\n", name));
-		if (*flink == '/') {
-			pstrcpy(cleanlink, flink);
-		} else {
-			pstrcpy(cleanlink, realdir);
-			pstrcat(cleanlink, "/");
-			pstrcat(cleanlink, flink);
-		}
-		unix_clean_name(cleanlink);
-
-		if (strncmp(cleanlink, realdir, reallen) != 0) {
-			DEBUG(2,("Bad access attempt? s=%s dir=%s newname=%s l=%d\n", name, realdir, cleanlink, (int)reallen));
-			ret = False;
-		}
-	}
-
-	vfs_ChDir(conn, savedir);
-	
-	return ret;
-}
-
 /*******************************************************************
  Reduce a file name, removing .. elements and checking that
- it is below dir in the heirachy. This uses vfs_GetWd() and so must be run
- on the system that has the referenced file system.
+ it is below dir in the heirachy. This uses realpath.
 ********************************************************************/
 
-BOOL reduce_name(connection_struct *conn, pstring s, const char *dir)
+BOOL reduce_name(connection_struct *conn, pstring fname)
 {
-#ifndef REDUCE_PATHS
-	return True;
+#ifdef REALPATH_TAKES_NULL
+	BOOL free_resolved_name = True;
 #else
-	pstring dir2;
-	pstring wd;
-	pstring base_name;
-	pstring newname;
-	char *p=NULL;
-	BOOL relative = (*s != '/');
-
-	*dir2 = *wd = *base_name = *newname = 0;
-
-	DEBUG(3,("reduce_name [%s] [%s]\n",s,dir));
-
-	/* We know there are no double slashes as this comes from srvstr_get_path().
-	   and has gone through check_path_syntax(). JRA */
-
-	pstrcpy(base_name,s);
-	p = strrchr_m(base_name,'/');
+#ifdef PATH_MAX
+        char resolved_name_buf[PATH_MAX+1];
+#else
+        pstring resolved_name_buf;
+#endif
+	BOOL free_resolved_name = False;
+#endif
+	char *resolved_name = NULL;
+	size_t con_path_len = strlen(conn->connectpath);
+	char *p = NULL;
 
-	if (!p)
-		return readlink_check(conn, dir, s);
+	DEBUG(3,("reduce_name [%s] [%s]\n", fname, conn->connectpath));
 
-	if (!vfs_GetWd(conn,wd)) {
-		DEBUG(0,("couldn't vfs_GetWd for %s %s\n",s,dir));
-		return(False);
-	}
+#ifdef REALPATH_TAKES_NULL
+	resolved_name = SMB_VFS_REALPATH(conn,fname,NULL);
+#else
+	resolved_name = SMB_VFS_REALPATH(conn,fname,resolved_name_buf);
+#endif
 
-	if (vfs_ChDir(conn,dir) != 0) {
-		DEBUG(0,("couldn't vfs_ChDir to %s\n",dir));
-		return(False);
+	if (!resolved_name) {
+		switch (errno) {
+			case ENOTDIR:
+				DEBUG(3,("reduce_name: Component not a directory in getting realpath for %s\n", fname));
+				return False;
+			case ENOENT:
+			{
+				pstring tmp_fname;
+				fstring last_component;
+				/* Last component didn't exist. Remove it and try and canonicalise the directory. */
+
+				pstrcpy(tmp_fname, fname);
+				p = strrchr_m(tmp_fname, '/');
+				if (p) {
+					*p++ = '\0';
+					fstrcpy(last_component, p);
+				}
+#ifdef REALPATH_TAKES_NULL
+				resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,NULL);
+#else
+				resolved_name = SMB_VFS_REALPATH(conn,tmp_fname,resolved_name_buf);
+#endif
+				if (!resolved_name) {
+					DEBUG(3,("reduce_name: couldn't get realpath for %s\n", fname));
+					return False;
+				}
+				pstrcpy(tmp_fname, resolved_name);
+				pstrcat(tmp_fname, "/");
+				pstrcat(tmp_fname, last_component);
+#ifdef REALPATH_TAKES_NULL
+				SAFE_FREE(resolved_name);
+				resolved_name = strdup(tmp_fname);
+				if (!resolved_name) {
+					DEBUG(0,("reduce_name: malloc fail for %s\n", tmp_fname));
+					return False;
+				}
+#else
+#ifdef PATH_MAX
+				safe_strcpy(resolved_name_buf, tmp_fname, PATH_MAX);
+#else
+				pstrcpy(pstring resolved_name_buf, tmp_fname);
+#endif
+				resolved_name = resolved_name_buf;
+#endif
+				break;
+			}
+			default:
+				DEBUG(1,("reduce_name: couldn't get realpath for %s\n", fname));
+				return False;
+		}
 	}
 
-	if (!vfs_GetWd(conn,dir2)) {
-		DEBUG(0,("couldn't vfs_GetWd for %s\n",dir));
-		vfs_ChDir(conn,wd);
-		return(False);
-	}
+	DEBUG(10,("reduce_name realpath [%s] -> [%s]\n", fname, resolved_name));
 
-	if (p && (p != base_name)) {
-		*p = 0;
-		if (strcmp(p+1,".")==0)
-			p[1]=0;
-		if (strcmp(p+1,"..")==0)
-			*p = '/';
+	if (*resolved_name != '/') {
+		DEBUG(0,("reduce_name: realpath doesn't return absolute paths !\n"));
+		if (free_resolved_name)
+			SAFE_FREE(resolved_name);
+		return False;
 	}
 
-	if (vfs_ChDir(conn,base_name) != 0) {
-		vfs_ChDir(conn,wd);
-		DEBUG(3,("couldn't vfs_ChDir for %s %s basename=%s\n",s,dir,base_name));
-		return(False);
+	if (strncmp(conn->connectpath, resolved_name, con_path_len) != 0) {
+		DEBUG(2, ("reduce_name: Bad access attemt: %s is a symlink outside the share path", fname));
+		if (free_resolved_name)
+			SAFE_FREE(resolved_name);
+		return False;
 	}
 
-	if (!vfs_GetWd(conn,newname)) {
-		vfs_ChDir(conn,wd);
-		DEBUG(2,("couldn't get vfs_GetWd for %s %s\n",s,base_name));
-		return(False);
+	/* Move path the connect path to the last part of the filename. */
+	p = resolved_name + con_path_len;
+	if (*p == '/') {
+		p++;
 	}
 
-	if (p && (p != base_name)) {
-		pstrcat(newname,"/");
-		pstrcat(newname,p+1);
+	if (!*p) {
+		pstrcpy(resolved_name, ".");
+		p = resolved_name;
 	}
 
-	{
-		size_t l = strlen(dir2);
-		char *last_slash = strrchr_m(dir2, '/');
-
-		if (last_slash && (last_slash[1] == '\0'))
-			l--;
-
-		if (strncmp(newname,dir2,l) != 0) {
-			vfs_ChDir(conn,wd);
-			DEBUG(2,("Bad access attempt: s=%s dir=%s newname=%s l=%d\n",s,dir2,newname,(int)l));
-			return(False);
-		}
-
-		if (!readlink_check(conn, dir, newname)) {
-			DEBUG(2, ("Bad access attemt: %s is a symlink outside the share path", s));
-			return(False);
-		}
-
-		if (relative) {
-			if (newname[l] == '/')
-				pstrcpy(s,newname + l + 1);
-			else
-				pstrcpy(s,newname+l);
-		} else
-			pstrcpy(s,newname);
+	if (!lp_symlinks(SNUM(conn)) && (strcmp(fname, p)!=0)) {
+		DEBUG(3,("reduce_name: denied: file path name %s is a symlink\n",fname));
+		if (free_resolved_name)
+			SAFE_FREE(resolved_name);
+		return False;
 	}
 
-	vfs_ChDir(conn,wd);
-
-	if (strlen(s) == 0)
-		pstrcpy(s,"./");
-
-	DEBUG(3,("reduced to %s\n",s));
+	DEBUG(3,("reduce_name: %s reduced to %s\n", fname, p));
+	if (free_resolved_name)
+		SAFE_FREE(resolved_name);
 	return(True);
-#endif
 }