gnu: nss: Fix CVE-2019-11745 via graft.

* gnu/packages/patches/nss-CVE-2019-11745.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/nss.scm (nss/fixed): New variable.
(nss)[replacement]: Add field.

gnu/local.mk

@@ -1180,6 +1180,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/ngircd-handle-zombies.patch		\
   %D%/packages/patches/nm-plugin-path.patch			\
   %D%/packages/patches/nsis-env-passthru.patch			\
+  %D%/packages/patches/nss-CVE-2019-11745.patch			\
   %D%/packages/patches/nss-freebl-stubs.patch			\
   %D%/packages/patches/nss-increase-test-timeout.patch		\
   %D%/packages/patches/nss-pkgconfig.patch			\

gnu/packages/nss.scm

@@ -71,6 +71,7 @@ (define-public nss
   (package
     (name "nss")
     (version "3.46.1")
+    (replacement nss/fixed)
     (source (origin
               (method url-fetch)
               (uri (let ((version-with-underscores
@@ -183,3 +184,11 @@ (define-public nss
 PKCS #5, PKCS #7, PKCS #11, PKCS #12, S/MIME, X.509 v3 certificates, and other
 security standards.")
     (license license:mpl2.0)))
+
+(define nss/fixed
+  (package
+    (inherit nss)
+    (source (origin
+              (inherit (package-source nss))
+              (patches (append (search-patches "nss-CVE-2019-11745.patch")
+                               (origin-patches (package-source nss))))))))

gnu/packages/patches/nss-CVE-2019-11745.patch

@@ -0,0 +1,24 @@
+Fix CVE-2019-11745 (Out-of-bounds write when passing an output buffer smaller
+than the block size to NSC_EncryptUpdate).
+
+Copied from Debian, equivalent to upstream fix:
+<https://hg.mozilla.org/projects/nss/rev/1e22a0c93afe9f46545560c86caedef9dab6cfda>.
+
+# HG changeset patch
+# User Craig Disselkoen <cdisselk@cs.ucsd.edu>
+# Date 1574189697 25200
+# Node ID 60bca7c6dc6dc44579b9b3e0fb62ca3b82d92eec
+# Parent  64e55c9f658e2a75f0835d00a8a1cdc2f25c74d6
+Bug 1586176 - EncryptUpdate should use maxout not block size. r=franziskus
+
+--- a/nss/lib/softoken/pkcs11c.c
++++ b/nss/lib/softoken/pkcs11c.c
+@@ -1285,7 +1285,7 @@ NSC_EncryptUpdate(CK_SESSION_HANDLE hSes
+             }
+             /* encrypt the current padded data */
+             rv = (*context->update)(context->cipherInfo, pEncryptedPart,
+-                                    &padoutlen, context->blockSize, context->padBuf,
++                                    &padoutlen, maxout, context->padBuf,
+                                     context->blockSize);
+             if (rv != SECSuccess) {
+                 return sftk_MapCryptError(PORT_GetError());