2.1.4.2 Signature Checking Using GnuPG

Another method of verifying the integrity and authenticity of a package is to use cryptographic signatures. This is more reliable than using MD5 checksums, but requires more work.

We sign MySQL downloadable packages with GnuPG (GNU Privacy Guard). GnuPG is an Open Source alternative to the well-known Pretty Good Privacy (PGP) by Phil Zimmermann. Most Linux distributions ship with GnuPG installed by default. Otherwise, see http://www.gnupg.org/ for more information about GnuPG and how to obtain and install it.

To verify the signature for a specific package, you first need to obtain a copy of our public GPG build key, which you can download from http://pgp.mit.edu/. The key that you want to obtain is named [e-mail]. The keyID for MySQL 5.7.37 packages and higher is 3A79BD29. After obtaining this key, you should compare it with the key shown following, before using it verify MySQL packages. Alternatively, you can copy and paste the key directly from the text below.

Note

The following public GPG build key is for MySQL 5.7.37 packages and higher. For the public GPG build key for earlier MySQL release packages (keyID 5072E1F5), see Section 2.1.4.5, “GPG Public Build Key for Archived Packages”.

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.1.6
Comment: Hostname: pgp.mit.edu

mQINBGG4urcBEACrbsRa7tSSyxSfFkB+KXSbNM9rxYqoB78u107skReefq4/+Y72TpDvlDZL
mdv/lK0IpLa3bnvsM9IE1trNLrfi+JES62kaQ6hePPgn2RqxyIirt2seSi3Z3n3jlEg+mSdh
AvW+b+hFnqxo+TY0U+RBwDi4oO0YzHefkYPSmNPdlxRPQBMv4GPTNfxERx6XvVSPcL1+jQ4R
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yl/Nipyr7WiQjCG0m3WfkjjVDTfs7/DXUqHFDOu4WMF9v+oqwpJXmAeGhQTWZC/QhWtrjrNJ
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sTSKHe+QnnnoFmu4gnmDU31i
=Xqbo
-----END PGP PUBLIC KEY BLOCK-----

To import the build key into your personal public GPG keyring, use gpg --import. For example, if you have saved the key in a file named mysql_pubkey.asc, the import command looks like this:

$> gpg --import mysql_pubkey.asc
gpg: key 3A79BD29: public key "MySQL Release Engineering
<[e-mail]>" imported
gpg: Total number processed: 1
gpg:               imported: 1
gpg: no ultimately trusted keys found

You can also download the key from the public keyserver using the public key id, 3A79BD29:

$> gpg --recv-keys 3A79BD29
gpg: requesting key 3A79BD29 from hkp server keys.gnupg.net
gpg: key 3A79BD29: "MySQL Release Engineering <[e-mail]>"
1 new user ID
gpg: key 3A79BD29: "MySQL Release Engineering <[e-mail]>"
53 new signatures
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:           new user IDs: 1
gpg:         new signatures: 53

If you want to import the key into your RPM configuration to validate RPM install packages, you should be able to import the key directly:

$> rpm --import mysql_pubkey.asc

If you experience problems or require RPM specific information, see Section 2.1.4.4, “Signature Checking Using RPM”.

After you have downloaded and imported the public build key, download your desired MySQL package and the corresponding signature, which also is available from the download page. The signature file has the same name as the distribution file with an .asc extension, as shown by the examples in the following table.

Table 2.1 MySQL Package and Signature Files for Source files

File Type	File Name
Distribution file	mysql-standard-5.7.44-linux-i686.tar.gz
Signature file	mysql-standard-5.7.44-linux-i686.tar.gz.asc

Make sure that both files are stored in the same directory and then run the following command to verify the signature for the distribution file:

$> gpg --verify package_name.asc

If the downloaded package is valid, you should see a Good signature message similar to this one:

$> gpg --verify mysql-standard-5.7.44-linux-i686.tar.gz.asc
gpg: Signature made Tue 01 Feb 2011 02:38:30 AM CST using DSA key ID 3A79BD29
gpg: Good signature from "MySQL Release Engineering <[e-mail]>"

The Good signature message indicates that the file signature is valid, when compared to the signature listed on our site. But you might also see warnings, like so:

$> gpg --verify mysql-standard-5.7.44-linux-i686.tar.gz.asc
gpg: Signature made Wed 23 Jan 2013 02:25:45 AM PST using DSA key ID 3A79BD29
gpg: checking the trustdb
gpg: no ultimately trusted keys found
gpg: Good signature from "MySQL Release Engineering <[e-mail]>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: A4A9 4068 76FC BD3C 4567  70C8 8C71 8D3B 5072 E1F5

That is normal, as they depend on your setup and configuration. Here are explanations for these warnings:

• gpg: no ultimately trusted keys found: This means that the specific key is not "ultimately trusted" by you or your web of trust, which is okay for the purposes of verifying file signatures.

• WARNING: This key is not certified with a trusted signature! There is no indication that the signature belongs to the owner.: This refers to your level of trust in your belief that you possess our real public key. This is a personal decision. Ideally, a MySQL developer would hand you the key in person, but more commonly, you downloaded it. Was the download tampered with? Probably not, but this decision is up to you. Setting up a web of trust is one method for trusting them.

See the GPG documentation for more information on how to work with public keys.