[GCrypt] ECDSA signing results can be smaller than the EC key size

• Component: New Bugs
• Status: RESOLVED FIXED

[Zan Dobersek]

See https://bugs.webkit.org/show_bug.cgi?id=171103#c8.

[Zan Dobersek]

Created attachment 312119 [details]
Patch

[Jiewen Tan]

Comment on attachment 312119 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=312119&action=review

Looks good to me. Please address the following comments.

> Source/WebCore/crypto/gcrypt/CryptoAlgorithmECDSAGCrypt.cpp:101
> +        if (dataSize >= keySizeInBytes) {

It will be good if we can fold this code and the one below into one.

Also, I am wondering if you are sure that the verification process can automatically remove the heading 0s.

[Zan Dobersek]

Comment on attachment 312119 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=312119&action=review

>> Source/WebCore/crypto/gcrypt/CryptoAlgorithmECDSAGCrypt.cpp:101
>> +        if (dataSize >= keySizeInBytes) {
> 
> It will be good if we can fold this code and the one below into one.
> 
> Also, I am wondering if you are sure that the verification process can automatically remove the heading 0s.

It removes the heading zeros while converting the binary data into MPIs.

[Zan Dobersek]

Created attachment 312297 [details]
Patch

[Jiewen Tan]

Comment on attachment 312297 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=312297&action=review

r=me

Looks good. Please address the following comments.

> Source/WebCore/crypto/gcrypt/CryptoAlgorithmECDSAGCrypt.cpp:117
> +        || extractECDSASignatureInteger(signature, signatureSexp, "s", keySizeInBytes))

Should be !extractECDSASignatureInteger(signature, signatureSexp, "s", keySizeInBytes)?

[Zan Dobersek]

Comment on attachment 312297 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=312297&action=review

>> Source/WebCore/crypto/gcrypt/CryptoAlgorithmECDSAGCrypt.cpp:117
>> +        || extractECDSASignatureInteger(signature, signatureSexp, "s", keySizeInBytes))
> 
> Should be !extractECDSASignatureInteger(signature, signatureSexp, "s", keySizeInBytes)?

Yes, was a mistake.

[Zan Dobersek]

Created attachment 312404 [details]
Patch for landing

[Zan Dobersek]

Comment on attachment 312404 [details]
Patch for landing

Clearing flags on attachment: 312404

Committed r217969: <http://trac.webkit.org/changeset/217969>

[Zan Dobersek]

All reviewed patches have been landed.  Closing bug.