[chore]: Bump golang.org/x/net from 0.27.0 to 0.28.0 (#3194)

Bumps [golang.org/x/net](https://github.com/golang/net) from 0.27.0 to 0.28.0.
- [Commits](https://github.com/golang/net/compare/v0.27.0...v0.28.0)

---
updated-dependencies:
- dependency-name: golang.org/x/net
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

1 files changed, 43 insertions, 1 deletions

diff --git a/vendor/golang.org/x/crypto/ssh/keys.go b/vendor/golang.org/x/crypto/ssh/keys.go
index 7967665f1..98e6706d5 100644
--- a/vendor/golang.org/x/crypto/ssh/keys.go
+++ b/vendor/golang.org/x/crypto/ssh/keys.go
@@ -488,7 +488,49 @@ func (r *rsaPublicKey) Verify(data []byte, sig *Signature) error {
 	h := hash.New()
 	h.Write(data)
 	digest := h.Sum(nil)
-	return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), hash, digest, sig.Blob)
+
+	// Signatures in PKCS1v15 must match the key's modulus in
+	// length. However with SSH, some signers provide RSA
+	// signatures which are missing the MSB 0's of the bignum
+	// represented. With ssh-rsa signatures, this is encouraged by
+	// the spec (even though e.g. OpenSSH will give the full
+	// length unconditionally). With rsa-sha2-* signatures, the
+	// verifier is allowed to support these, even though they are
+	// out of spec. See RFC 4253 Section 6.6 for ssh-rsa and RFC
+	// 8332 Section 3 for rsa-sha2-* details.
+	//
+	// In practice:
+	// * OpenSSH always allows "short" signatures:
+	//   https://github.com/openssh/openssh-portable/blob/V_9_8_P1/ssh-rsa.c#L526
+	//   but always generates padded signatures:
+	//   https://github.com/openssh/openssh-portable/blob/V_9_8_P1/ssh-rsa.c#L439
+	//
+	// * PuTTY versions 0.81 and earlier will generate short
+	//   signatures for all RSA signature variants. Note that
+	//   PuTTY is embedded in other software, such as WinSCP and
+	//   FileZilla. At the time of writing, a patch has been
+	//   applied to PuTTY to generate padded signatures for
+	//   rsa-sha2-*, but not yet released:
+	//   https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=a5bcf3d384e1bf15a51a6923c3724cbbee022d8e
+	//
+	// * SSH.NET versions 2024.0.0 and earlier will generate short
+	//   signatures for all RSA signature variants, fixed in 2024.1.0:
+	//   https://github.com/sshnet/SSH.NET/releases/tag/2024.1.0
+	//
+	// As a result, we pad these up to the key size by inserting
+	// leading 0's.
+	//
+	// Note that support for short signatures with rsa-sha2-* may
+	// be removed in the future due to such signatures not being
+	// allowed by the spec.
+	blob := sig.Blob
+	keySize := (*rsa.PublicKey)(r).Size()
+	if len(blob) < keySize {
+		padded := make([]byte, keySize)
+		copy(padded[keySize-len(blob):], blob)
+		blob = padded
+	}
+	return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), hash, digest, blob)
 }
 
 func (r *rsaPublicKey) CryptoPublicKey() crypto.PublicKey {