This commit refactors the code in `cmd/crypto`
and separates SSE-S3, SSE-C and SSE-KMS.
This commit should not cause any behavior change
except for:
- `IsRequested(http.Header)`
which now returns the requested type {SSE-C, SSE-S3,
SSE-KMS} and does not consider SSE-C copy headers.
However, SSE-C copy headers alone are anyway not valid.
In certain organizations policy claim names
can be not just 'policy' but also things like
'roles', the value of this field might also
be *string* or *[]string* support this as well
In this PR we are still not supporting multiple
policies per STS account which will require a
more comprehensive change.
Currently when connections to vault fail, client
perpetually retries this leads to assumptions that
the server has issues and masks the problem.
Re-purpose *crypto.Error* type to send appropriate
errors back to the client.
This commit allows the MinIO server to parse the metadata if:
- either the `X-Minio-Internal-Server-Side-Encryption-S3-Key-Id`
and the `X-Minio-Internal-Server-Side-Encryption-S3-Kms-Sealed-Key`
entries are present.
- or *both* headers are not present.
This is in service to support a K/V data key store.
This commit adds two functions for sealing/unsealing the
etag (a.k.a. content MD5) in case of SSE single-part upload.
Sealing the ETag is neccessary in case of SSE-S3 to preserve
the security guarantees. In case of SSE-S3 AWS returns the
content-MD5 of the plaintext object as ETag. However, we
must not store the MD5 of the plaintext for encrypted objects.
Otherwise it becomes possible for an attacker to detect
equal/non-equal encrypted objects. Therefore we encrypt
the ETag before storing on the backend. But we only need
to encrypt the ETag (content-MD5) if the client send it -
otherwise the client cannot verify it anyway.
This commit adds two functions for removing
confidential information - like SSE-C keys -
from HTTP headers / object metadata.
This creates a central point grouping all
headers/entries which must be filtered / removed.
See also https://github.com/minio/minio/pull/6489#discussion_r219797993
of #6489
* crypto: add support for parsing SSE-C/SSE-S3 metadata
This commit adds support for detecting and parsing
SSE-C/SSE-S3 object metadata. With the `IsEncrypted`
functions it is possible to determine whether an object
seems to be encrypted. With the `ParseMetadata` functions
it is possible to validate such metadata and extract the
SSE-C/SSE-S3 related values.
It also fixes some naming issues.
* crypto: add functions for creating SSE object metadata
This commit adds functions for creating SSE-S3 and
SSE-C metadata. It also adds a `CreateMultipartMetadata`
for creating multipart metadata.
For all functions unit tests are included.
Andreas Auernhammer