Bug#969369: buster-pu: package node-elliptic/6.4.1_dfsg-1+deb10u1

[Xavier Guimard <yadd@debian.org>]

Package: release.debian.org
Severity: normal
Tags: buster
User: release.debian.org@packages.debian.org
Usertags: pu

[ Reason ]
node-elliptic allows ECDSA signature maleability via variations in
encoding, leading '\0' bytes, or integer overflows (CVE-2020-13822).

[ Impact ]
This could conceivably have a security-relevant impact if an application
relied on a single canonical signature.

[ Tests ]
No new test, however upstream tests are OK during build and autopkgtest

[ Risks ]
Upstream change is little (just some tests on inputs) and test coverage
seems good

[ Checklist ]
  [X] *all* changes are documented in the d/changelog
  [X] I reviewed all changes and I approve them
  [X] attach debdiff against the package in (old)stable
  [X] the issue is verified as fixed in unstable

[ Changes ]
Just some checks on inputs

diff --git a/debian/changelog b/debian/changelog
index 74b516f..3bc7a59 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+node-elliptic (6.4.1~dfsg-1+deb10u1) buster; urgency=medium
+
+  * Prevent malleability and overflows (Closes: CVE-2020-13822)
+
+ -- Xavier Guimard <yadd@debian.org>  Tue, 01 Sep 2020 13:24:44 +0200
+
 node-elliptic (6.4.1~dfsg-1) unstable; urgency=medium
 
   [ upstream ]
diff --git a/debian/patches/CVE-2020-13822.patch b/debian/patches/CVE-2020-13822.patch
new file mode 100644
index 0000000..179ecb9
--- /dev/null
+++ b/debian/patches/CVE-2020-13822.patch
@@ -0,0 +1,89 @@
+Description: signature: prevent malleability and overflows
+ CVE-2020-13822
+Author: Fedor Indutny <fedor@indutny.com>
+Origin: upstream, https://github.com/indutny/elliptic/commit/856fe4d9
+Bug: https://github.com/indutny/elliptic/issues/226
+Forwarded: not-needed
+Reviewed-By: Xavier Guimard <yadd@debian.org>
+Last-Update: 2020-09-01
+
+--- a/lib/elliptic/ec/signature.js
++++ b/lib/elliptic/ec/signature.js
+@@ -33,11 +33,24 @@
+     return initial;
+   }
+   var octetLen = initial & 0xf;
++
++  // Indefinite length or overflow
++  if (octetLen === 0 || octetLen > 4) {
++    return false;
++  }
++
+   var val = 0;
+   for (var i = 0, off = p.place; i < octetLen; i++, off++) {
+     val <<= 8;
+     val |= buf[off];
++    val >>>= 0;
+   }
++
++  // Leading zeroes
++  if (val <= 0x7f) {
++    return false;
++  }
++
+   p.place = off;
+   return val;
+ }
+@@ -61,6 +74,9 @@
+     return false;
+   }
+   var len = getLength(data, p);
++  if (len === false) {
++    return false;
++  }
+   if ((len + p.place) !== data.length) {
+     return false;
+   }
+@@ -68,21 +84,37 @@
+     return false;
+   }
+   var rlen = getLength(data, p);
++  if (rlen === false) {
++    return false;
++  }
+   var r = data.slice(p.place, rlen + p.place);
+   p.place += rlen;
+   if (data[p.place++] !== 0x02) {
+     return false;
+   }
+   var slen = getLength(data, p);
++  if (slen === false) {
++    return false;
++  }
+   if (data.length !== slen + p.place) {
+     return false;
+   }
+   var s = data.slice(p.place, slen + p.place);
+-  if (r[0] === 0 && (r[1] & 0x80)) {
+-    r = r.slice(1);
+-  }
+-  if (s[0] === 0 && (s[1] & 0x80)) {
+-    s = s.slice(1);
++  if (r[0] === 0) {
++    if (r[1] & 0x80) {
++      r = r.slice(1);
++    } else {
++      // Leading zeroes
++      return false;
++    }
++  }
++  if (s[0] === 0) {
++    if (s[1] & 0x80) {
++      s = s.slice(1);
++    } else {
++      // Leading zeroes
++      return false;
++    }
+   }
+ 
+   this.r = new BN(r);
diff --git a/debian/patches/series b/debian/patches/series
index 0ee9429..d86ab76 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -1 +1,2 @@
 use-assert.patch
+CVE-2020-13822.patch