From: Matthew Ogilvie <mmogilvi+fml@zoho.com>
Date: Fri, 9 Jun 2017 19:31:17 -0600
Subject: give each ctl it's own copy of password
Git-repo: https://gitlab.com/fetchmail/fetchmail.git
Git-commit: 469b0a212e7f047ab16ef46a9158df5fb373e8c2

pwdb_* and passwordfile options may free and re-allocate password
for each poll operation.  Giving each context it's own copy of
the password should prevent accessing freed memory in another copy.

I haven't tested pwmd, but these seem like obvious fixes.
---
 fetchmail.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Index: fetchmail-6.5.1/fetchmail.c
===================================================================
--- fetchmail-6.5.1.orig/fetchmail.c
+++ fetchmail-6.5.1/fetchmail.c
@@ -470,7 +470,7 @@ int main(int argc, char **argv)
 	    if (NO_PASSWORD(ctl))
 		/* Server won't care what the password is, but there
 		   must be some non-null string here.  */
-		ctl->password = ctl->remotename;
+		ctl->password = xstrdup(ctl->remotename);
 	    else if (!ctl->passwordfile && ctl->passwordfd==-1)
 	    {
 		const netrc_entry *p;
@@ -1118,7 +1118,15 @@ static void optmerge(struct query *h2, s
 
     FLAG_MERGE(wildcard);
     STRING_MERGE(remotename);
-    STRING_MERGE(password);
+    if (force ? !!h1->password : !h2->password) {
+	if (h2->password) {
+		memset(h2->password, 0x55, strlen(h2->password));
+		xfree(h2->password);
+	}
+	if (h1->password) {
+	    h2->password = xstrdup(h1->password);
+	}
+    }
     FLAG_MERGE(passwordfile);
     if (force ? h1->passwordfd!=-1 : h2->passwordfd==-1) {
 	h2->passwordfd = h1->passwordfd;