From 230ee31a543a79da41cf918f987ecdbf8072b461 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 fe5ce6535..9ed4e5be8 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ mbed TLS ChangeLog (Sorted per branch, date) += mbed TLS 2.1.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 2.1.7 branch released 2017-03-08 Security diff --git a/library/rsa.c b/library/rsa.c index e83187526..d6b7a0330 100644 --- a/library/rsa.c +++ b/library/rsa.c @@ -1375,7 +1375,11 @@ int mbedtls_rsa_rsassa_pkcs1_v15_verify( mbedtls_rsa_context *ctx, return( MBEDTLS_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( MBEDTLS_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 af168805f..5013ac8b0 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:MBEDTLS_SHA512_C:MBEDTLS_PKCS1_V15 mbedtls_rsa_pkcs1_verify:"59779fd2a39e56640c4fc1e67b60aeffcecd78aed7ad2bdfa464e93d04198d48466b8da7445f25bfa19db2844edd5c8f539cf772cc132b483169d390db28a43bc4ee0f038f6568ffc87447746cb72fefac2d6d90ee3143a915ac4688028805905a68eb8f8a96674b093c495eddd8704461eaa2b345efbb2ad6930acd8023f870":MBEDTLS_RSA_PKCS_V15:MBEDTLS_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:MBEDTLS_SHA512_C:MBEDTLS_PKCS1_V15 mbedtls_rsa_pkcs1_sign:"59779fd2a39e56640c4fc1e67b60aeffcecd78aed7ad2bdfa464e93d04198d48466b8da7445f25bfa19db2844edd5c8f539cf772cc132b483169d390db28a43bc4ee0f038f6568ffc87447746cb72fefac2d6d90ee3143a915ac4688028805905a68eb8f8a96674b093c495eddd8704461eaa2b345efbb2ad6930acd8023f870":MBEDTLS_RSA_PKCS_V15:MBEDTLS_MD_SHA512:1536:16:"c8c67df894c882045ede26a9008ab09ea0672077d7bc71d412511cd93981ddde8f91b967da404056c39f105f7f239abdaff92923859920f6299e82b95bd5b8c959948f4a035cbd693ad83014294d349813d1ad57911a6355d0731fe3a034e9db":16:"f15147d0e7c04a1e3f37adde802cdc610999bf7ab0088434aaeda0c0ab3910b14d2ce56cb66bffd97552195fae8b061077e03920814d8b9cfb5a3958b3a82c2a7fc97e55db5978b47a922156eb8a3e55c06a54a45d1670abdfb995489c4d0051":16:"bd429bb7c3b00bbea19ba664c0f8172d1a73c3cfa05e2ed656d570c1590918bb7e372ed25e2cd71395ba0a9b1a30f3ee012ffb0546cab8e3581fe3e23f44ab57a8aee9717e71a936a580fa8572d450fb00339a6f6704b717df0c149a465bab768c61500cd93b61113ff3e4389167f7b2c8e3c0da2d4765286bee555b0bcb4998f59b14fad03180a17c8b4f69bcd1234f4ae85950137665ac2ba80b55cc9b1aafb454b83771aa755acd2a00e93ddb65e696dbed8bdca69fb5e0c5c2097b9cfe4b":16:"3":"93b6fa99485c116ca6efdd4202ea1cf49f4c6345fae692584413743ce5b65510e8e4690aee9a19ea1ff10d57f22aa3548d839f28a8525a34354e9e58e0f3947e056ce2554e21bf287e220b98db3b551258cd42b495e5d1a3bbc83c9d1a02f2a300ef6d866ea75108e44ebb3e16b47df2f6de28feb2be3874dbbf21599451082d86e9f2f462575a8185c69aa1f1fcb6a363c5d71aeba2103449eaf3845285291148d5f78d1646b8dc95cbcc4082f987d948b0e7d4e80b60595f8a7517584e1643":0