Messages in this thread | | | Subject | Re: [PATCH v2] X.509: unpack RSA signatureValue field from BIT STRING | From | Kamil Konieczny <> | Date | Tue, 17 Apr 2018 17:07:37 +0200 |
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On 17.04.2018 15:39, Maciej S. Szmigiero wrote: > The signatureValue field of a X.509 certificate is encoded as a BIT STRING. > For RSA signatures this BIT STRING is of so-called primitive subtype, which > contains a u8 prefix indicating a count of unused bits in the encoding. > > We have to strip this prefix from signature data, just as we already do for > key data in x509_extract_key_data() function. > > This wasn't noticed earlier because this prefix byte is zero for RSA key > sizes divisible by 8. Since BIT STRING is a big-endian encoding adding zero > prefixes has no bearing on its value. > > The signature length, however was incorrect, which is a problem for RSA > implementations that need it to be exactly correct (like AMD CCP). > > Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
your e-mail address looks incorrect
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-- Best regards, Kamil Konieczny Samsung R&D Institute Poland
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