When EcGenerateKey() is called with PublicKeySize set to zero or
less than the required size,
it returns the size of the required buffer with failure.
However, EcGenerateKey() generates a key and then checks
if the buffer size is insufficient.
This can be optimised by moving the public key size check
before generating the key.
Therefore, optimise to avoid unnecessary key generation.
Signed-off-by: levi.yun <yeoreum....@arm.com>
---
Notes:
v2:
- Fix missing spceial case when (PublicKey == NULL && PublicKeySize == 0)
This changes can be seen at
https://github.com/LeviYeoReum/edk2/tree/2716_not_generate_key_on_fail_size_v2
CryptoPkg/Library/BaseCryptLib/Pk/CryptEc.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/CryptoPkg/Library/BaseCryptLib/Pk/CryptEc.c
b/CryptoPkg/Library/BaseCryptLib/Pk/CryptEc.c
index
d8cc9ba0e8f968f6cbd9ac4c56018f9a4392cd0b..4ec1903440acdc20e7b71ce8c17fe32bdfa7bab9
100644
--- a/CryptoPkg/Library/BaseCryptLib/Pk/CryptEc.c
+++ b/CryptoPkg/Library/BaseCryptLib/Pk/CryptEc.c
@@ -497,18 +497,23 @@ EcGenerateKey (
Group = EC_KEY_get0_group (EcKey);
HalfSize = (EC_GROUP_get_degree (Group) + 7) / 8;
+ if ((PublicKey != NULL) && (*PublicKeySize < HalfSize * 2)) {
+ *PublicKeySize = HalfSize * 2;
+ return FALSE;
+ }
+
// Assume RAND_seed was called
if (EC_KEY_generate_key (EcKey) != 1) {
return FALSE;
}
- if (*PublicKeySize < HalfSize * 2) {
- *PublicKeySize = HalfSize * 2;
- return FALSE;
- }
-
*PublicKeySize = HalfSize * 2;
+ // If PublicKey is NULL and PublicKeySize is 0, return True and fill
PublickKeySize with correct Key Size.
+ if (PublicKey == NULL) {
+ return TRUE;
+ }
+
EcPoint = EC_KEY_get0_public_key (EcKey);
if (EcPoint == NULL) {
return FALSE;
--
Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")
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