diff options
author | Junio C Hamano <gitster@pobox.com> | 2014-10-09 00:05:15 +0400 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2014-10-09 00:05:25 +0400 |
commit | fb06b5280ea05d75515fa780cf08d4ec9d6fe101 (patch) | |
tree | 9d7c7032df370076149f31f3373e067b69248169 /Documentation | |
parent | 325602ce120e7bd7321b9ed409b49b48fd20888e (diff) | |
parent | 6f5ef44e0d8933621fcd50127518557013002313 (diff) |
Merge branch 'jc/push-cert'
Allow "git push" request to be signed, so that it can be verified and
audited, using the GPG signature of the person who pushed, that the
tips of branches at a public repository really point the commits
the pusher wanted to, without having to "trust" the server.
* jc/push-cert: (24 commits)
receive-pack::hmac_sha1(): copy the entire SHA-1 hash out
signed push: allow stale nonce in stateless mode
signed push: teach smart-HTTP to pass "git push --signed" around
signed push: fortify against replay attacks
signed push: add "pushee" header to push certificate
signed push: remove duplicated protocol info
send-pack: send feature request on push-cert packet
receive-pack: GPG-validate push certificates
push: the beginning of "git push --signed"
pack-protocol doc: typofix for PKT-LINE
gpg-interface: move parse_signature() to where it should be
gpg-interface: move parse_gpg_output() to where it should be
send-pack: clarify that cmds_sent is a boolean
send-pack: refactor inspecting and resetting status and sending commands
send-pack: rename "new_refs" to "need_pack_data"
receive-pack: factor out capability string generation
send-pack: factor out capability string generation
send-pack: always send capabilities
send-pack: refactor decision to send update per ref
send-pack: move REF_STATUS_REJECT_NODELETE logic a bit higher
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/config.txt | 19 | ||||
-rw-r--r-- | Documentation/git-push.txt | 9 | ||||
-rw-r--r-- | Documentation/git-receive-pack.txt | 65 | ||||
-rw-r--r-- | Documentation/technical/pack-protocol.txt | 49 | ||||
-rw-r--r-- | Documentation/technical/protocol-capabilities.txt | 13 |
5 files changed, 148 insertions, 7 deletions
diff --git a/Documentation/config.txt b/Documentation/config.txt index 3b5b24aeb7f..04a1e2f37e9 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -2044,6 +2044,25 @@ receive.autogc:: receiving data from git-push and updating refs. You can stop it by setting this variable to false. +receive.certnonceseed:: + By setting this variable to a string, `git receive-pack` + will accept a `git push --signed` and verifies it by using + a "nonce" protected by HMAC using this string as a secret + key. + +receive.certnonceslop:: + When a `git push --signed` sent a push certificate with a + "nonce" that was issued by a receive-pack serving the same + repository within this many seconds, export the "nonce" + found in the certificate to `GIT_PUSH_CERT_NONCE` to the + hooks (instead of what the receive-pack asked the sending + side to include). This may allow writing checks in + `pre-receive` and `post-receive` a bit easier. Instead of + checking `GIT_PUSH_CERT_NONCE_SLOP` environment variable + that records by how many seconds the nonce is stale to + decide if they want to accept the certificate, they only + can check `GIT_PUSH_CERT_NONCE_STATUS` is `OK`. + receive.fsckObjects:: If it is set to true, git-receive-pack will check all received objects. It will abort in the case of a malformed object or a diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt index c0d7403b9a1..b17283ab7a1 100644 --- a/Documentation/git-push.txt +++ b/Documentation/git-push.txt @@ -10,7 +10,8 @@ SYNOPSIS -------- [verse] 'git push' [--all | --mirror | --tags] [--follow-tags] [-n | --dry-run] [--receive-pack=<git-receive-pack>] - [--repo=<repository>] [-f | --force] [--prune] [-v | --verbose] [-u | --set-upstream] + [--repo=<repository>] [-f | --force] [--prune] [-v | --verbose] + [-u | --set-upstream] [--signed] [--force-with-lease[=<refname>[:<expect>]]] [--no-verify] [<repository> [<refspec>...]] @@ -129,6 +130,12 @@ already exists on the remote side. from the remote but are pointing at commit-ish that are reachable from the refs being pushed. +--signed:: + GPG-sign the push request to update refs on the receiving + side, to allow it to be checked by the hooks and/or be + logged. See linkgit:git-receive-pack[1] for the details + on the receiving end. + --receive-pack=<git-receive-pack>:: --exec=<git-receive-pack>:: Path to the 'git-receive-pack' program on the remote diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt index b1f7dc643a0..9016960e271 100644 --- a/Documentation/git-receive-pack.txt +++ b/Documentation/git-receive-pack.txt @@ -53,6 +53,56 @@ the update. Refs to be created will have sha1-old equal to 0\{40}, while refs to be deleted will have sha1-new equal to 0\{40}, otherwise sha1-old and sha1-new should be valid objects in the repository. +When accepting a signed push (see linkgit:git-push[1]), the signed +push certificate is stored in a blob and an environment variable +`GIT_PUSH_CERT` can be consulted for its object name. See the +description of `post-receive` hook for an example. In addition, the +certificate is verified using GPG and the result is exported with +the following environment variables: + +`GIT_PUSH_CERT_SIGNER`:: + The name and the e-mail address of the owner of the key that + signed the push certificate. + +`GIT_PUSH_CERT_KEY`:: + The GPG key ID of the key that signed the push certificate. + +`GIT_PUSH_CERT_STATUS`:: + The status of GPG verification of the push certificate, + using the same mnemonic as used in `%G?` format of `git log` + family of commands (see linkgit:git-log[1]). + +`GIT_PUSH_CERT_NONCE`:: + The nonce string the process asked the signer to include + in the push certificate. If this does not match the value + recorded on the "nonce" header in the push certificate, it + may indicate that the certificate is a valid one that is + being replayed from a separate "git push" session. + +`GIT_PUSH_CERT_NONCE_STATUS`:: +`UNSOLICITED`;; + "git push --signed" sent a nonce when we did not ask it to + send one. +`MISSING`;; + "git push --signed" did not send any nonce header. +`BAD`;; + "git push --signed" sent a bogus nonce. +`OK`;; + "git push --signed" sent the nonce we asked it to send. +`SLOP`;; + "git push --signed" sent a nonce different from what we + asked it to send now, but in a previous session. See + `GIT_PUSH_CERT_NONCE_SLOP` environment variable. + +`GIT_PUSH_CERT_NONCE_SLOP`:: + "git push --signed" sent a nonce different from what we + asked it to send now, but in a different session whose + starting time is different by this many seconds from the + current session. Only meaningful when + `GIT_PUSH_CERT_NONCE_STATUS` says `SLOP`. + Also read about `receive.certnonceslop` variable in + linkgit:git-config[1]. + This hook is called before any refname is updated and before any fast-forward checks are performed. @@ -101,9 +151,14 @@ the update. Refs that were created will have sha1-old equal to 0\{40}, otherwise sha1-old and sha1-new should be valid objects in the repository. +The `GIT_PUSH_CERT*` environment variables can be inspected, just as +in `pre-receive` hook, after accepting a signed push. + Using this hook, it is easy to generate mails describing the updates to the repository. This example script sends one mail message per -ref listing the commits pushed to the repository: +ref listing the commits pushed to the repository, and logs the push +certificates of signed pushes with good signatures to a logger +service: #!/bin/sh # mail out commit update information. @@ -119,6 +174,14 @@ ref listing the commits pushed to the repository: fi | mail -s "Changes to ref $ref" commit-list@mydomain done + # log signed push certificate, if any + if test -n "${GIT_PUSH_CERT-}" && test ${GIT_PUSH_CERT_STATUS} = G + then + ( + echo expected nonce is ${GIT_PUSH_NONCE} + git cat-file blob ${GIT_PUSH_CERT} + ) | mail -s "push certificate from $GIT_PUSH_CERT_SIGNER" push-log@mydomain + fi exit 0 The exit code from this hook invocation is ignored, however a diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt index 569c48a352b..462e20645f1 100644 --- a/Documentation/technical/pack-protocol.txt +++ b/Documentation/technical/pack-protocol.txt @@ -212,9 +212,9 @@ out of what the server said it could do with the first 'want' line. want-list = first-want *additional-want - shallow-line = PKT_LINE("shallow" SP obj-id) + shallow-line = PKT-LINE("shallow" SP obj-id) - depth-request = PKT_LINE("deepen" SP depth) + depth-request = PKT-LINE("deepen" SP depth) first-want = PKT-LINE("want" SP obj-id SP capability-list LF) additional-want = PKT-LINE("want" SP obj-id LF) @@ -465,7 +465,7 @@ contain all the objects that the server will need to complete the new references. ---- - update-request = *shallow command-list [pack-file] + update-request = *shallow ( command-list | push-cert ) [pack-file] shallow = PKT-LINE("shallow" SP obj-id LF) @@ -481,12 +481,27 @@ references. old-id = obj-id new-id = obj-id + push-cert = PKT-LINE("push-cert" NUL capability-list LF) + PKT-LINE("certificate version 0.1" LF) + PKT-LINE("pusher" SP ident LF) + PKT-LINE("pushee" SP url LF) + PKT-LINE("nonce" SP nonce LF) + PKT-LINE(LF) + *PKT-LINE(command LF) + *PKT-LINE(gpg-signature-lines LF) + PKT-LINE("push-cert-end" LF) + pack-file = "PACK" 28*(OCTET) ---- If the receiving end does not support delete-refs, the sending end MUST NOT ask for delete command. +If the receiving end does not support push-cert, the sending end +MUST NOT send a push-cert command. When a push-cert command is +sent, command-list MUST NOT be sent; the commands recorded in the +push certificate is used instead. + The pack-file MUST NOT be sent if the only command used is 'delete'. A pack-file MUST be sent if either create or update command is used, @@ -501,6 +516,34 @@ was being processed (the obj-id is still the same as the old-id), and it will run any update hooks to make sure that the update is acceptable. If all of that is fine, the server will then update the references. +Push Certificate +---------------- + +A push certificate begins with a set of header lines. After the +header and an empty line, the protocol commands follow, one per +line. + +Currently, the following header fields are defined: + +`pusher` ident:: + Identify the GPG key in "Human Readable Name <email@address>" + format. + +`pushee` url:: + The repository URL (anonymized, if the URL contains + authentication material) the user who ran `git push` + intended to push into. + +`nonce` nonce:: + The 'nonce' string the receiving repository asked the + pushing user to include in the certificate, to prevent + replay attacks. + +The GPG signature lines are a detached signature for the contents +recorded in the push certificate before the signature block begins. +The detached signature is used to certify that the commands were +given by the pusher, who must be the signer. + Report Status ------------- diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt index e1743438472..0c92deebcca 100644 --- a/Documentation/technical/protocol-capabilities.txt +++ b/Documentation/technical/protocol-capabilities.txt @@ -18,8 +18,8 @@ was sent. Server MUST NOT ignore capabilities that client requested and server advertised. As a consequence of these rules, server MUST NOT advertise capabilities it does not understand. -The 'report-status', 'delete-refs', and 'quiet' capabilities are sent and -recognized by the receive-pack (push to server) process. +The 'report-status', 'delete-refs', 'quiet', and 'push-cert' capabilities +are sent and recognized by the receive-pack (push to server) process. The 'ofs-delta' and 'side-band-64k' capabilities are sent and recognized by both upload-pack and receive-pack protocols. The 'agent' capability @@ -250,3 +250,12 @@ allow-tip-sha1-in-want If the upload-pack server advertises this capability, fetch-pack may send "want" lines with SHA-1s that exist at the server but are not advertised by upload-pack. + +push-cert=<nonce> +----------------- + +The receive-pack server that advertises this capability is willing +to accept a signed push certificate, and asks the <nonce> to be +included in the push certificate. A send-pack client MUST NOT +send a push-cert packet unless the receive-pack server advertises +this capability. |