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 in to check that the error that is detected first is indeed the
padding rather than the final length check).
diff --git a/tests/suites/test_suite_rsa.data b/tests/suites/test_suite_rsa.data
index af16880..5013ac8 100644
--- a/tests/suites/test_suite_rsa.data
+++ b/tests/suites/test_suite_rsa.data
@@ -134,6 +134,10 @@
 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