cryptobyte: fix panic due to malformed ASN.1 inputs on 32-bit archs

When int is 32 bits wide (on 32-bit architectures like 386 and arm), an
overflow could occur, causing a panic, due to malformed ASN.1 being
passed to any of the ASN1 methods of String.

Tested on linux/386 and darwin/amd64.

This fixes CVE-2020-7919 and was found thanks to the Project Wycheproof
test vectors.

Change-Id: I8c9696a8bfad1b40ec877cd740dba3467d66ab54
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/645211
Reviewed-by: Katie Hockman <katiehockman@google.com>
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/216677
Run-TryBot: Katie Hockman <katie@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
4 files changed
tree: 844c120ad80e0145967f4245a4c5bb3d56b9008b
  1. acme/
  2. argon2/
  3. bcrypt/
  4. blake2b/
  5. blake2s/
  6. blowfish/
  7. bn256/
  8. cast5/
  9. chacha20/
  10. chacha20poly1305/
  11. cryptobyte/
  12. curve25519/
  13. ed25519/
  14. hkdf/
  15. internal/
  16. md4/
  17. nacl/
  18. ocsp/
  19. openpgp/
  20. otr/
  21. pbkdf2/
  22. pkcs12/
  23. poly1305/
  24. ripemd160/
  25. salsa20/
  26. scrypt/
  27. sha3/
  28. ssh/
  29. tea/
  30. twofish/
  31. xtea/
  32. xts/
  33. .gitattributes
  34. .gitignore
  35. AUTHORS
  36. codereview.cfg
  37. CONTRIBUTING.md
  38. CONTRIBUTORS
  39. go.mod
  40. go.sum
  41. LICENSE
  42. PATENTS
  43. README.md
README.md

Go Cryptography

This repository holds supplementary Go cryptography libraries.

Download/Install

The easiest way to install is to run go get -u golang.org/x/crypto/.... You can also manually git clone the repository to $GOPATH/src/golang.org/x/crypto.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see https://golang.org/doc/contribute.html.

The main issue tracker for the crypto repository is located at https://github.com/golang/go/issues. Prefix your issue with “x/crypto:” in the subject line, so it is easy to find.

Note that contributions to the cryptography package receive additional scrutiny due to their sensitive nature. Patches may take longer than normal to receive feedback.