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List:       amanda-hackers
Subject:    
From:       JOERG SPECHT <joerg.specht () ins ! uni-stuttgart ! de>
Date:       2001-01-09 9:16:12
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Hello,

the password for smbclient is passed as command-line argument.
On most systems, one can view that with the `ps' command.
So I think that solution is inacceptable.

smbclient offers the possiblity to pass $PASSWD_FD or $PASSWD_FILE, so 
I have choosen $PASSWD_FD. The password is written in a pipe(), whose
reading end stays open until execution of smbclient. The file
descriptor number is written into $PASSWD_FD.


["diffed-amanda-2.4.2-PASSWD_FD" (text/plain)]

diff -ur old/amanda-2.4.2/client-src/findpass.c new/amanda-2.4.2/client-src/findpass.c
--- old/amanda-2.4.2/client-src/findpass.c	Wed Oct 11 04:08:26 2000
+++ new/amanda-2.4.2/client-src/findpass.c	Tue Jan  9 09:27:53 2001
@@ -29,22 +29,35 @@
  * Support routines for Amanda SAMBA support
  */
 
+#include <limits.h>
 #include "findpass.h"
 
 /*
  * Find the Samba password and optional domain for a given disk.
  * Returns pointers into an alloc-ed area.  The caller should clear them
  * as soon as reasonable.
+ *
+ * Secret part is written into a pipe and $PASSWD_FD ist set,
+ * use findpass(NULL, NULL) to explicitly clear it.
  */
 
 char *findpass(disk, domain)
 char *disk, **domain;
 {
+  static int pw_fd = -1;
   FILE *fp;
   static char *buffer = NULL;
   char *s, *d, *pw = NULL;
   int ch;
 
+  /* in any case: reset $PASSWD_FD-pipe */
+  if(pw_fd >= 0)
+    close(pw_fd);
+  pw_fd = -1;
+  putenv("PASSWD_FD");
+  if(disk == NULL && domain == NULL)
+    return NULL;
+
   *domain = NULL;				/* just to be sure */
   if ( (fp = fopen("/etc/amandapass", "r")) ) {
     amfree(buffer);
@@ -80,6 +93,34 @@
     }
     afclose(fp);
   }
+
+  if(pw) {
+    static char putenv_buf[100];
+    int l, pipe_fd[2];
+    char *secret;
+
+    secret = strchr(pw, '%');
+    if(secret != NULL)
+      *(secret++) = '\0';			/* string ends after username */
+    else
+      secret = pw + strlen(pw);			/* empty secret */
+    l = strlen(secret);
+
+#ifndef PIPE_BUF
+#define PIPE_BUF	_POSIX_PIPE_BUF
+#endif
+    /* necessary: secret must be written by one write() atomically. */
+    if(l <= PIPE_BUF && pipe(pipe_fd) >= 0) {	/* pipe() has not FD_CLOEXEC */
+      write(pipe_fd[1], secret, l);		/* buffered in kernel */
+      close(pipe_fd[1]);			/* hopefully does not wait */
+      pw_fd = pipe_fd[0];			/* must be held open */
+      sprintf(putenv_buf, "PASSWD_FD=%d", pw_fd);
+      putenv(putenv_buf);			/* putenv_buf must be static */
+    }
+
+    memset(secret, '\0', l);			/* surely make it unreadable */
+  }
+
   return pw;
 }
 
diff -ur old/amanda-2.4.2/client-src/selfcheck.c new/amanda-2.4.2/client-src/selfcheck.c
--- old/amanda-2.4.2/client-src/selfcheck.c	Tue Oct 31 02:00:24 2000
+++ new/amanda-2.4.2/client-src/selfcheck.c	Tue Jan  9 09:32:24 2001
@@ -298,6 +298,7 @@
 		return;
 	    }
 	    if ((device = makesharename(disk, 1)) == NULL) {
+		findpass(NULL, NULL);
 		memset(pass, '\0', strlen(pass));
 		amfree(pass);
 		if(domain) {
@@ -329,6 +330,7 @@
 		printf("ERROR [PC SHARE %s access error: host down or invalid password?]\n", disk);
 	    else
 		printf("OK %s\n", disk);
+	    findpass(NULL, NULL);
 	    memset(cmd, '\0', strlen(cmd));
 	    amfree(cmd);
 	    return;
diff -ur old/amanda-2.4.2/client-src/sendbackup-gnutar.c new/amanda-2.4.2/client-src/sendbackup-gnutar.c
--- old/amanda-2.4.2/client-src/sendbackup-gnutar.c	Wed Oct 11 04:08:26 2000
+++ new/amanda-2.4.2/client-src/sendbackup-gnutar.c	Tue Jan  9 09:47:16 2001
@@ -302,6 +302,7 @@
 	    error("[invalid samba host or password not found?]");
 	}
 	if ((sharename = makesharename(disk, 0)) == 0) {
+	    findpass(NULL, NULL);
 	    memset(pass, '\0', strlen(pass));
 	    amfree(pass);
 	    if(domain) {
@@ -367,6 +368,7 @@
 			    estr ? estr : skip_argument,
 			    (char *) 0);
 	tarpid = dumppid;
+	findpass(NULL, NULL);
 	memset(pass, '\0', strlen(pass));
 	amfree(pass);
 	if(domain) {
diff -ur old/amanda-2.4.2/client-src/sendsize.c new/amanda-2.4.2/client-src/sendsize.c
--- old/amanda-2.4.2/client-src/sendsize.c	Wed Oct 11 04:08:26 2000
+++ new/amanda-2.4.2/client-src/sendsize.c	Mon Jan  8 14:14:58 2001
@@ -933,6 +933,7 @@
 	error("[sendsize : error in smbtar diskline, unable to find password]");
     }
     if ((sharename = makesharename(disk, 0)) == NULL) {
+        findpass(NULL, NULL);
 	memset(pass, '\0', strlen(pass));
 	amfree(pass);
 	if(domain) {
@@ -969,6 +970,7 @@
 	      domain ? domain : skip_argument,
 	      "-c", tarkeys,
 	      (char *)0);
+    findpass(NULL, NULL);
     memset(pass, '\0', strlen(pass));
     amfree(pass);
     if(domain) {
diff -ur old/amanda-2.4.2/common-src/alloc.c new/amanda-2.4.2/common-src/alloc.c
--- old/amanda-2.4.2/common-src/alloc.c	Thu Sep  9 01:26:35 1999
+++ new/amanda-2.4.2/common-src/alloc.c	Mon Jan  8 12:41:55 2001
@@ -451,6 +451,7 @@
 {
     static char *safe_env_list[] = {
 	"TZ",
+	"PASSWD_FD",
 	NULL
     };
 


Bugs:
- User is not informed about errors, he may just wonder why it does
  not work

Compatibility (those worked on SunOS-5.7):
- I hope PIPE_BUF (or _POSIX_PIPE_BUF) is defined on most systems
- close() of the writing end of the pipe should have no delay
- putenv() is a SYSV function, maybe BSD should use setenv()

Anyway, good luck
=09=09-- J=F6rg Specht --


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