From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Thu, 25 Jul 2019 18:41:57 +0000 (+0100)
Subject: De-taint library-return string for inet_ntoa() etc
X-Git-Url: https://git.exim.org/users/jgh/exim.git/commitdiff_plain/f8d78f744328266ad9f7f48cf5ca8f7d67c227c4?ds=inline

De-taint library-return string for inet_ntoa() etc
---

diff --git a/src/src/host.c b/src/src/host.c
index a00d048f6..30d54b481 100644
--- a/src/src/host.c
+++ b/src/src/host.c
@@ -945,13 +945,15 @@ else
 
 /* If there is no buffer, put the string into some new store. */
 
-if (buffer == NULL) return string_copy(yield);
+if (!buffer) buffer = store_get(46, FALSE);
 
 /* Callers of this function with a non-NULL buffer must ensure that it is
 large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
-makes this use of strcpy() OK. */
+makes this use of strcpy() OK.
+If the library returned apparently an apparently tainted string, clean it;
+we trust IP addresses. */
 
-Ustrcpy(buffer, yield);
+string_format_nt(buffer, 46, "%s", yield);
 return buffer;
 }