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| author | Sandrine Bailleux <sandrine.bailleux@arm.com> | 2020-02-17 13:41:59 +0100 |
|---|---|---|
| committer | Sandrine Bailleux <sandrine.bailleux@arm.com> | 2020-02-18 09:46:55 +0100 |
| commit | 495599cd0a56143f9e5159f354b5718ac84e7431 (patch) | |
| tree | f01f0e4a83dcf5de4dfbef366be74c1ce96c2b94 /drivers | |
| parent | 956059385cf2532924e1023f9d5156aed2f78f4b (diff) | |
| download | platform_external_arm-trusted-firmware-495599cd0a56143f9e5159f354b5718ac84e7431.tar.gz platform_external_arm-trusted-firmware-495599cd0a56143f9e5159f354b5718ac84e7431.tar.bz2 platform_external_arm-trusted-firmware-495599cd0a56143f9e5159f354b5718ac84e7431.zip | |
TBBR: Reduce size of ECDSA key buffers
The TBBR implementation extracts public keys from certificates and
stores them in static buffers. DER-encoded ECDSA keys are only 91 bytes
each but were each allocated 294 bytes instead. Reducing the size of
these buffers saves 609 bytes of BSS in BL2 (294 - 91 = 203 bytes for
each of the 3 key buffers in use).
Also add a comment claryfing that key buffers are tailored on RSA key
sizes when both ECDSA and RSA keys are used.
Change-Id: Iad332856e7af1f9814418d012fba3e1e9399f72a
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/auth/tbbr/tbbr_cot.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/auth/tbbr/tbbr_cot.c b/drivers/auth/tbbr/tbbr_cot.c index 6dd4ae252..2f1f451b1 100644 --- a/drivers/auth/tbbr/tbbr_cot.c +++ b/drivers/auth/tbbr/tbbr_cot.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved. + * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ @@ -18,7 +18,12 @@ /* - * Maximum key and hash sizes (in DER format) + * Maximum key and hash sizes (in DER format). + * + * Both RSA and ECDSA keys may be used at the same time. In this case, the key + * buffers must be big enough to hold either. As RSA keys are bigger than ECDSA + * ones for all key sizes we support, they impose the minimum size of these + * buffers. */ #if TF_MBEDTLS_USE_RSA #if TF_MBEDTLS_KEY_SIZE == 1024 @@ -32,8 +37,8 @@ #else #error "Invalid value for TF_MBEDTLS_KEY_SIZE" #endif -#else -#define PK_DER_LEN 294 +#else /* Only using ECDSA keys. */ +#define PK_DER_LEN 91 #endif #define HASH_DER_LEN 83 |