Address potential DoS with high compression ratio

Resolves: RHEL-28697

Signed-off-by: Rafael Guterres Jeffman <rjeffman@redhat.com>

0001-Address-potential-DoS-with-high-compression-ratio_rhel#28697.patch

@@ -0,0 +1,74 @@
+From 90477a3b6e73da69740e00b8161f53fea19b831f Mon Sep 17 00:00:00 2001
+From: Simo Sorce <simo@redhat.com>
+Date: Tue, 5 Mar 2024 16:57:17 -0500
+Subject: [PATCH] Address potential DoS with high compression ratio
+
+Fixes CVE-2024-28102
+
+Signed-off-by: Simo Sorce <simo@redhat.com>
+---
+ jwcrypto/jwe.py   |  7 +++++++
+ jwcrypto/tests.py | 26 ++++++++++++++++++++++++++
+ 2 files changed, 33 insertions(+)
+
+diff --git a/jwcrypto/jwe.py b/jwcrypto/jwe.py
+index 9412881..5df500b 100644
+--- a/jwcrypto/jwe.py
++++ b/jwcrypto/jwe.py
+@@ -9,5 +10,8 @@
+ from jwcrypto.jwa import JWA
+ 
++# Limit the amount of data we are willing to decompress by default.
++default_max_compressed_size = 256 * 1024
++
+ 
+ # RFC 7516 - 4.1
+ # name: (description, supported?)
+@@ -374,6 +374,10 @@ def _decrypt(self, key, ppe):
+ 
+         compress = jh.get('zip', None)
+         if compress == 'DEF':
++            if len(data) > default_max_compressed_size:
++                raise InvalidJWEData(
++                    'Compressed data exceeds maximum allowed'
++                    'size' + f' ({default_max_compressed_size})')
+             self.plaintext = zlib.decompress(data, -zlib.MAX_WBITS)
+         elif compress is None:
+             self.plaintext = data
+diff --git a/jwcrypto/tests.py b/jwcrypto/tests.py
+index bb2ff10..59049f8 100644
+--- a/jwcrypto/tests.py
++++ b/jwcrypto/tests.py
+@@ -1196,6 +1196,32 @@ def test_pbes2_hs256_aeskw_custom_params(self):
+         check.deserialize(enc, key)
+         self.assertEqual(b'plain', check.payload)
+ 
++    def test_jwe_decompression_max(self):
++        key = jwk.JWK(kty='oct', k=base64url_encode(b'A' * (128 // 8)))
++        payload = '{"u": "' + "u" * 400000000 + '", "uu":"' \
++            + "u" * 400000000 + '"}'
++        protected_header = {
++            "alg": "A128KW",
++            "enc": "A128GCM",
++            "typ": "JWE",
++            "zip": "DEF",
++        }
++        enc = jwe.JWE(payload.encode('utf-8'),
++                      recipient=key,
++                      protected=protected_header).serialize(compact=True)
++        with self.assertRaises(jwe.InvalidJWEData):
++            check = jwe.JWE()
++            check.deserialize(enc)
++            check.decrypt(key)
++
++        defmax = jwe.default_max_compressed_size
++        jwe.default_max_compressed_size = 1000000000
++        # ensure we can eraise the limit and decrypt
++        check = jwe.JWE()
++        check.deserialize(enc)
++        check.decrypt(key)
++        jwe.default_max_compressed_size = defmax
++
+ 
+ class JWATests(unittest.TestCase):
+     def test_jwa_create(self):

python-jwcrypto.spec

@@ -16,13 +16,15 @@
 
 Name:           python-%{srcname}
 Version:        0.5.0
-Release:        1.1%{?dist}
+Release:        2%{?dist}
 Summary:        Implements JWK, JWS, JWE specifications using python-cryptography
 
 License:        LGPLv3+
 URL:            https://github.com/latchset/%{srcname}
 Source0:        https://github.com/latchset/%{srcname}/releases/download/v%{version}/%{srcname}-%{version}.tar.gz
 
+Patch1:         0001-Address-potential-DoS-with-high-compression-ratio_rhel#28697.patch
+
 BuildArch:      noarch
 %if %{with python2}
 BuildRequires:  python2-devel
@@ -64,6 +66,7 @@ Implements JWK, JWS, JWE specifications using python-cryptography
 %prep
 %setup -q -n %{srcname}-%{version}
 
+%autopatch -p 1
 
 %build
 %if %{with python2}
@@ -114,6 +117,10 @@ rm -rf %{buildroot}/usr/share/doc/jwcrypto
 
 
 %changelog
+* Wed Apr 03 2024 Rafael Jeffman <rjeffman@redhat.com> - 0.5.0-2
+- Address potential DoS with high compression ratio
+  Resolves: RHEL-28697
+
 * Fri Jun 17 2022 Christian Heimes <cheimes@redhat.com> - 0.5.0-1.1
 - Bump dist to solve version sorting issue, fixes RHBZ#2097800