On Wed, Sep 16, 2020 at 02:44:45PM +0200, Heinrich Schuchardt wrote:
On 16.09.20 14:05, Joakim Tjernlund wrote:
On Wed, 2020-09-16 at 13:55 +0200, Heinrich Schuchardt wrote:
On 16.09.20 13:40, Joakim Tjernlund wrote:
On Wed, 2020-09-16 at 13:14 +0200, Heinrich Schuchardt wrote:
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On 16.09.20 10:13, AKASHI Takahiro wrote:
On Wed, Sep 16, 2020 at 01:19:03AM +0200, Heinrich Schuchardt wrote: > On 9/11/20 7:26 PM, Andrii Voloshyn wrote: >> Hi there, >> >> Does U-boot take into account certificate expiration date when verifying signed images in FIT? In other words, is date stored along with the public key in DTB file? >> >> Cheers, >> Andy >> > > Hello Philippe, > > looking at padding_pkcs_15_verify() in lib/rsa/rsa-verify.c I cannot > find a comparison of the date on which an image was signed with the > expiry date of the certificate. Shouldn't there be a check? Or did I > simply look into the wrong function?
I think Simon is the right person to answer this question, but
as far as I know, we don't have any device tree property for the expiration date of a public key. See doc/uImage.FIT/signature.txt.
Yes, the problem starts with mkimage not writing the dates available in the X509 certificate into the device tree.
The dates are accessible via the X509_get0_notBefore() and X509_get0_notAfter() functions of the OpenSSL library.
Takahiro, could you, please, also look at the UEFI secure boot implementation in U-Boot. EDK2 validates the dates via the embedded OpenSSL library in CryptoPkg/Library/OpensslLib/openssl/crypto/x509/x509_vfy.c, function verify_chain(). We should not do less.
Does that mean that verified boot stops/fails when the date expires ? How do you guarantee that the device has the correct time ?
Jocke
We talking of the validity time range of the public key and the date of signature of the intermediate certificates and the loaded image. No RTC
OK, but still: will an invalid time range then stop booting ?
If you use a certificate that is valid until 2019 to sign an image or an intermediate certificate in 2020, the image must not be loaded.
Well, I'm not confident that pckcs7_verify_one() does this. (Probably not.)
-Takahiro Akashi
Best regards
Heinrich