diff options
| author | Andrew Duda | 2016-11-08 18:53:40 +0000 |
|---|---|---|
| committer | Tom Rini | 2016-11-21 14:07:30 -0500 |
| commit | da29f2991d75fc8aa3289407a0e686a4a22f8c9e (patch) | |
| tree | 3c972878a859196e72be31fe6da6d0ae5047d38b /lib/sha256.c | |
| parent | 5300a4f9336291fb713fcfaf9ea6e51b71824800 (diff) | |
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 <aduda@meraki.com>
Signed-off-by: aduda <aduda@meraki.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'lib/sha256.c')
| -rw-r--r-- | lib/sha256.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/sha256.c b/lib/sha256.c index bb338baefa8..7f5a3618d0d 100644 --- a/lib/sha256.c +++ b/lib/sha256.c @@ -15,6 +15,12 @@ #include <watchdog.h> #include <u-boot/sha256.h> +const uint8_t sha256_der_prefix[SHA256_DER_LEN] = { + 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, + 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, + 0x00, 0x04, 0x20 +}; + /* * 32-bit integer manipulation macros (big endian) */ |