gnu: ytnef: Fix CVE-2021-3403 and CVE-2021-3404.

* gnu/packages/patches/ytnef-CVE-2021-3403.patch,
gnu/packages/patches/ytnef-CVE-2021-3404.patch: New patches.
* gnu/local.mk (dist_patch_DATA): Register them.
* gnu/packages/mail.scm (ytnef): Apply them.

1 files changed, 32 insertions, 0 deletions

diff --git a/gnu/packages/patches/ytnef-CVE-2021-3403.patch b/gnu/packages/patches/ytnef-CVE-2021-3403.patch
new file mode 100644
index 0000000000..4b1c9d659f
--- /dev/null
+++ b/gnu/packages/patches/ytnef-CVE-2021-3403.patch
@@ -0,0 +1,32 @@
+From f2380a53fb84d370eaf6e6c3473062c54c57fac7 Mon Sep 17 00:00:00 2001
+From: Oliver Giles <ohw.giles@gmail.com>
+Date: Mon, 1 Feb 2021 10:12:16 +1300
+Subject: [PATCH] Prevent potential double-free in TNEFSubjectHandler
+
+If TNEFSubjectHandler is called multiple times, but the last time
+failed due to the PREALLOCCHECK, the subject.data member will be
+a freed, but invalid pointer. To prevent a double-free next time
+TNEFSubjectHandler is entered, set it to zero after freeing.
+
+Resolves: #85
+Reported-by: jasperla
+---
+ lib/ytnef.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/lib/ytnef.c b/lib/ytnef.c
+index b148719..b06c807 100644
+--- a/lib/ytnef.c
++++ b/lib/ytnef.c
+@@ -301,8 +301,10 @@ int TNEFFromHandler STD_ARGLIST {
+ }
+ // -----------------------------------------------------------------------------
+ int TNEFSubjectHandler STD_ARGLIST {
+-  if (TNEF->subject.data)
++  if (TNEF->subject.data) {
+     free(TNEF->subject.data);
++    TNEF->subject.data = NULL;
++  }
+ 
+   PREALLOCCHECK(size, 100);
+   TNEF->subject.data = calloc(size+1, sizeof(BYTE));