From 19c10e9984acaef5a5fb4c15965b982fc1728d1f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Manuel=20P=C3=A9gouri=C3=A9-Gonnard?= Date: Thu, 11 May 2017 12:49:51 +0200 Subject: [PATCH] RSA PKCS1v1.5 verification: check padding length The test case was generated by modifying our signature code so that it produces a 7-byte long padding (which also means garbage at the end, so it is essential to check that the error that is detected first is indeed the padding rather than the final length check). --- ChangeLog | 6 ++++++ library/rsa.c | 6 +++++- tests/suites/test_suite_rsa.data | 4 ++++ 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index b46c72879b..832810bf28 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ mbed TLS ChangeLog (Sorted per branch, date) += mbed TLS 1.3.x branch released xxxx-xx-xx + +Security + * Tighten parsing of RSA PKCS#1 v1.5 signatures, to avoid a + potential Bleichenbacher/BERserk-style attack. + = mbed TLS 1.3.19 branch released 2017-03-08 Security diff --git a/library/rsa.c b/library/rsa.c index 79726c1b53..9a4134c851 100644 --- a/library/rsa.c +++ b/library/rsa.c @@ -1376,7 +1376,11 @@ int rsa_rsassa_pkcs1_v15_verify( rsa_context *ctx, return( POLARSSL_ERR_RSA_INVALID_PADDING ); p++; } - p++; + p++; /* skip 00 byte */ + + /* We've read: 00 01 PS 00 where PS must be at least 8 bytes */ + if( p - buf < 11 ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); len = siglen - ( p - buf ); diff --git a/tests/suites/test_suite_rsa.data b/tests/suites/test_suite_rsa.data index e4bc89eec2..2c62990761 100644 --- a/tests/suites/test_suite_rsa.data +++ b/tests/suites/test_suite_rsa.data @@ -134,6 +134,10 @@ RSA PKCS1 Verify v1.5 CAVS #34 depends_on:POLARSSL_SHA512_C:POLARSSL_PKCS1_V15 rsa_pkcs1_verify:"59779fd2a39e56640c4fc1e67b60aeffcecd78aed7ad2bdfa464e93d04198d48466b8da7445f25bfa19db2844edd5c8f539cf772cc132b483169d390db28a43bc4ee0f038f6568ffc87447746cb72fefac2d6d90ee3143a915ac4688028805905a68eb8f8a96674b093c495eddd8704461eaa2b345efbb2ad6930acd8023f870":RSA_PKCS_V15:POLARSSL_MD_SHA512:1536:16:"a59d9b7269b102b7be684ec5e28db79992e6d3231e77c90b78960c2638b35ef6dbdac1ac59e7249d96d426e7f99397eabc6b8903fe1942da580322b98bafacd81bb911c29666f83886a2a2864f3552044300e60cedd5a8c321c43e280413dc41673c39a11b98a885486f8187a70f270185c4c12bc48a1968305269776c070ef69d4913589a887c4d0f5e7dd58bd806d0d49a14a1762c38665cef4646ff13a0cd29c3a60460703c3d051d5b28c660bffb5f8bd43d495ffa64175f72b8abe5fddd":16:"11":"0b4d96f411c727a262d6d0ade34195b78603551061917d060f89add47b09dfe8715f4f9147d327dc25e91fe457e5d1a2f22cd8fe6fe8e29d2060658307c87a40640650fef3d4b289a6c3febc5a100b29a8b56623afb29fd3c13ea372bf3c638c1db25f8bd8c74c821beec7b5affcace1d05d056a6c2d3035926c7a268df4751a54bc20a6b8cfd729a7cba309ae817daccbef9950a482cf23950a8ca1d3a13ddb7d8d0f87ad5587d4d9ebe19fe93457597a7bdd056c2fd4cea7d31e4a0e595a7b":0 +RSA PKCS1 Verify v1.5 padding too short +depends_on:MBEDTLS_SHA1_C:MBEDTLS_PKCS1_V15 +mbedtls_rsa_pkcs1_verify:"AABBCC03020100FFFFFFFFFF1122330A0B0CCCDDDDDDDDDD":MBEDTLS_RSA_PKCS_V15:MBEDTLS_MD_SHA1:1024:16:"9292758453063D803DD603D5E777D7888ED1D5BF35786190FA2F23EBC0848AEADDA92CA6C3D80B32C4D109BE0F36D6AE7130B9CED7ACDF54CFC7555AC14EEBAB93A89813FBF3C4F8066D2D800F7C38A81AE31942917403FF4946B0A83D3D3E05EE57C6F5F5606FB5D4BC6CD34EE0801A5E94BB77B07507233A0BC7BAC8F90F79":16:"10001":"6edd56f397d9bc6d176bbe3d80946fc352ad6127b85b1d67d849c0a38cbde7222c5fafbb18dcef791178a8e15f5c8cd91869f8ca4b758c46ce3e229bf666d2e3e296544351bcb5db7e0004f6c0800f76a432071297e405759d4324d1cf1c412758be93a39f834e03dee59e28ac571ce2b0b3c8fe639979f516223b54027340a5":MBEDTLS_ERR_RSA_INVALID_PADDING + RSA PKCS1 Sign #1 (SHA512, 1536 bits RSA) depends_on:POLARSSL_SHA512_C:POLARSSL_PKCS1_V15 rsa_pkcs1_sign:"59779fd2a39e56640c4fc1e67b60aeffcecd78aed7ad2bdfa464e93d04198d48466b8da7445f25bfa19db2844edd5c8f539cf772cc132b483169d390db28a43bc4ee0f038f6568ffc87447746cb72fefac2d6d90ee3143a915ac4688028805905a68eb8f8a96674b093c495eddd8704461eaa2b345efbb2ad6930acd8023f870":RSA_PKCS_V15:POLARSSL_MD_SHA512:1536:16:"c8c67df894c882045ede26a9008ab09ea0672077d7bc71d412511cd93981ddde8f91b967da404056c39f105f7f239abdaff92923859920f6299e82b95bd5b8c959948f4a035cbd693ad83014294d349813d1ad57911a6355d0731fe3a034e9db":16:"f15147d0e7c04a1e3f37adde802cdc610999bf7ab0088434aaeda0c0ab3910b14d2ce56cb66bffd97552195fae8b061077e03920814d8b9cfb5a3958b3a82c2a7fc97e55db5978b47a922156eb8a3e55c06a54a45d1670abdfb995489c4d0051":16:"bd429bb7c3b00bbea19ba664c0f8172d1a73c3cfa05e2ed656d570c1590918bb7e372ed25e2cd71395ba0a9b1a30f3ee012ffb0546cab8e3581fe3e23f44ab57a8aee9717e71a936a580fa8572d450fb00339a6f6704b717df0c149a465bab768c61500cd93b61113ff3e4389167f7b2c8e3c0da2d4765286bee555b0bcb4998f59b14fad03180a17c8b4f69bcd1234f4ae85950137665ac2ba80b55cc9b1aafb454b83771aa755acd2a00e93ddb65e696dbed8bdca69fb5e0c5c2097b9cfe4b":16:"3":"93b6fa99485c116ca6efdd4202ea1cf49f4c6345fae692584413743ce5b65510e8e4690aee9a19ea1ff10d57f22aa3548d839f28a8525a34354e9e58e0f3947e056ce2554e21bf287e220b98db3b551258cd42b495e5d1a3bbc83c9d1a02f2a300ef6d866ea75108e44ebb3e16b47df2f6de28feb2be3874dbbf21599451082d86e9f2f462575a8185c69aa1f1fcb6a363c5d71aeba2103449eaf3845285291148d5f78d1646b8dc95cbcc4082f987d948b0e7d4e80b60595f8a7517584e1643":0