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/sha1.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/u-boot/sha1.h') 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 -- cgit