From da29f2991d75fc8aa3289407a0e686a4a22f8c9e Mon Sep 17 00:00:00 2001 From: Andrew Duda Date: Tue, 8 Nov 2016 18:53:40 +0000 Subject: rsa: Verify RSA padding programatically Padding verification was done against static SHA/RSA pair arrays which take up a lot of static memory, are mostly 0xff, and cannot be reused for additional SHA/RSA pairings. The padding can be easily computed according to PKCS#1v2.1 as: EM = 0x00 || 0x01 || PS || 0x00 || T where PS is (emLen - tLen - 3) octets of 0xff and T is DER encoding of the hash. Store DER prefix in checksum_algo and create rsa_verify_padding function to handle verification of a message for any SHA/RSA pairing. Signed-off-by: Andrew Duda Signed-off-by: aduda Reviewed-by: Simon Glass --- include/u-boot/rsa-checksum.h | 4 ---- include/u-boot/sha1.h | 3 +++ include/u-boot/sha256.h | 3 +++ 3 files changed, 6 insertions(+), 4 deletions(-) (limited to 'include/u-boot') diff --git a/include/u-boot/rsa-checksum.h b/include/u-boot/rsa-checksum.h index 3c69d85ecb..c240720249 100644 --- a/include/u-boot/rsa-checksum.h +++ b/include/u-boot/rsa-checksum.h @@ -12,10 +12,6 @@ #include #include -extern const uint8_t padding_sha256_rsa4096[]; -extern const uint8_t padding_sha256_rsa2048[]; -extern const uint8_t padding_sha1_rsa2048[]; - /** * hash_calculate() - Calculate hash over the data * diff --git a/include/u-boot/sha1.h b/include/u-boot/sha1.h index b0d9ce9db9..2634a29c20 100644 --- a/include/u-boot/sha1.h +++ b/include/u-boot/sha1.h @@ -21,6 +21,9 @@ extern "C" { #define SHA1_SUM_POS -0x20 #define SHA1_SUM_LEN 20 +#define SHA1_DER_LEN 15 + +extern const uint8_t sha1_der_prefix[]; /** * \brief SHA-1 context structure diff --git a/include/u-boot/sha256.h b/include/u-boot/sha256.h index beadab35ff..9aa1251789 100644 --- a/include/u-boot/sha256.h +++ b/include/u-boot/sha256.h @@ -2,6 +2,9 @@ #define _SHA256_H #define SHA256_SUM_LEN 32 +#define SHA256_DER_LEN 19 + +extern const uint8_t sha256_der_prefix[]; /* Reset watchdog each time we process this many bytes */ #define CHUNKSZ_SHA256 (64 * 1024) -- cgit v1.2.3