diff options
author | Brandon Williams <bmwill@google.com> | 2016-12-15 01:39:52 +0300 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2016-12-15 20:29:13 +0300 |
commit | f1762d772e9b415a3163abf5f217fc3b71a3b40e (patch) | |
tree | 763946ed8ce07f24b1ad95a1ba71b497eee796d2 | |
parent | f962ddf6edb199b2611d575a75f60d20d5c137c3 (diff) |
transport: add protocol policy config option
Previously the `GIT_ALLOW_PROTOCOL` environment variable was used to
specify a whitelist of protocols to be used in clone/fetch/push
commands. This patch introduces new configuration options for more
fine-grained control for allowing/disallowing protocols. This also has
the added benefit of allowing easier construction of a protocol
whitelist on systems where setting an environment variable is
non-trivial.
Now users can specify a policy to be used for each type of protocol via
the 'protocol.<name>.allow' config option. A default policy for all
unconfigured protocols can be set with the 'protocol.allow' config
option. If no user configured default is made git will allow known-safe
protocols (http, https, git, ssh, file), disallow known-dangerous
protocols (ext), and have a default policy of `user` for all other
protocols.
The supported policies are `always`, `never`, and `user`. The `user`
policy can be used to configure a protocol to be usable when explicitly
used by a user, while disallowing it for commands which run
clone/fetch/push commands without direct user intervention (e.g.
recursive initialization of submodules). Commands which can potentially
clone/fetch/push from untrusted repositories without user intervention
can export `GIT_PROTOCOL_FROM_USER` with a value of '0' to prevent
protocols configured to the `user` policy from being used.
Fix remote-ext tests to use the new config to allow the ext
protocol to be tested.
Based on a patch by Jeff King <peff@peff.net>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r-- | Documentation/config.txt | 46 | ||||
-rw-r--r-- | Documentation/git.txt | 38 | ||||
-rwxr-xr-x | git-submodule.sh | 12 | ||||
-rw-r--r-- | t/lib-proto-disable.sh | 130 | ||||
-rwxr-xr-x | t/t5509-fetch-push-namespaces.sh | 1 | ||||
-rwxr-xr-x | t/t5802-connect-helper.sh | 1 | ||||
-rw-r--r-- | transport.c | 75 |
7 files changed, 264 insertions, 39 deletions
diff --git a/Documentation/config.txt b/Documentation/config.txt index 8153336435..50d3d06ffa 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -2260,6 +2260,52 @@ pretty.<name>:: Note that an alias with the same name as a built-in format will be silently ignored. +protocol.allow:: + If set, provide a user defined default policy for all protocols which + don't explicitly have a policy (`protocol.<name>.allow`). By default, + if unset, known-safe protocols (http, https, git, ssh, file) have a + default policy of `always`, known-dangerous protocols (ext) have a + default policy of `never`, and all other protocols have a default + policy of `user`. Supported policies: ++ +-- + +* `always` - protocol is always able to be used. + +* `never` - protocol is never able to be used. + +* `user` - protocol is only able to be used when `GIT_PROTOCOL_FROM_USER` is + either unset or has a value of 1. This policy should be used when you want a + protocol to be directly usable by the user but don't want it used by commands which + execute clone/fetch/push commands without user input, e.g. recursive + submodule initialization. + +-- + +protocol.<name>.allow:: + Set a policy to be used by protocol `<name>` with clone/fetch/push + commands. See `protocol.allow` above for the available policies. ++ +The protocol names currently used by git are: ++ +-- + - `file`: any local file-based path (including `file://` URLs, + or local paths) + + - `git`: the anonymous git protocol over a direct TCP + connection (or proxy, if configured) + + - `ssh`: git over ssh (including `host:path` syntax, + `ssh://`, etc). + + - `http`: git over http, both "smart http" and "dumb http". + Note that this does _not_ include `https`; if you want to configure + both, you must do so individually. + + - any external helpers are named by their protocol (e.g., use + `hg` to allow the `git-remote-hg` helper) +-- + pull.ff:: By default, Git does not create an extra merge commit when merging a commit that is a descendant of the current commit. Instead, the diff --git a/Documentation/git.txt b/Documentation/git.txt index 923aa49db7..d9fb937586 100644 --- a/Documentation/git.txt +++ b/Documentation/git.txt @@ -1129,30 +1129,20 @@ of clones and fetches. cloning a repository to make a backup). `GIT_ALLOW_PROTOCOL`:: - If set, provide a colon-separated list of protocols which are - allowed to be used with fetch/push/clone. This is useful to - restrict recursive submodule initialization from an untrusted - repository. Any protocol not mentioned will be disallowed (i.e., - this is a whitelist, not a blacklist). If the variable is not - set at all, all protocols are enabled. The protocol names - currently used by git are: - - - `file`: any local file-based path (including `file://` URLs, - or local paths) - - - `git`: the anonymous git protocol over a direct TCP - connection (or proxy, if configured) - - - `ssh`: git over ssh (including `host:path` syntax, - `ssh://`, etc). - - - `http`: git over http, both "smart http" and "dumb http". - Note that this does _not_ include `https`; if you want both, - you should specify both as `http:https`. - - - any external helpers are named by their protocol (e.g., use - `hg` to allow the `git-remote-hg` helper) - + If set to a colon-separated list of protocols, behave as if + `protocol.allow` is set to `never`, and each of the listed + protocols has `protocol.<name>.allow` set to `always` + (overriding any existing configuration). In other words, any + protocol not mentioned will be disallowed (i.e., this is a + whitelist, not a blacklist). See the description of + `protocol.allow` in linkgit:git-config[1] for more details. + +`GIT_PROTOCOL_FROM_USER`:: + Set to 0 to prevent protocols used by fetch/push/clone which are + configured to the `user` state. This is useful to restrict recursive + submodule initialization from an untrusted repository or for programs + which feed potentially-untrusted URLS to git commands. See + linkgit:git-config[1] for more details. Discussion[[Discussion]] ------------------------ diff --git a/git-submodule.sh b/git-submodule.sh index 78fdac9568..fc440761af 100755 --- a/git-submodule.sh +++ b/git-submodule.sh @@ -22,14 +22,10 @@ require_work_tree wt_prefix=$(git rev-parse --show-prefix) cd_to_toplevel -# Restrict ourselves to a vanilla subset of protocols; the URLs -# we get are under control of a remote repository, and we do not -# want them kicking off arbitrary git-remote-* programs. -# -# If the user has already specified a set of allowed protocols, -# we assume they know what they're doing and use that instead. -: ${GIT_ALLOW_PROTOCOL=file:git:http:https:ssh} -export GIT_ALLOW_PROTOCOL +# Tell the rest of git that any URLs we get don't come +# directly from the user, so it can apply policy as appropriate. +GIT_PROTOCOL_FROM_USER=0 +export GIT_PROTOCOL_FROM_USER command= branch= diff --git a/t/lib-proto-disable.sh b/t/lib-proto-disable.sh index be88e9a00f..02f49cb409 100644 --- a/t/lib-proto-disable.sh +++ b/t/lib-proto-disable.sh @@ -1,10 +1,7 @@ # Test routines for checking protocol disabling. -# test cloning a particular protocol -# $1 - description of the protocol -# $2 - machine-readable name of the protocol -# $3 - the URL to try cloning -test_proto () { +# Test clone/fetch/push with GIT_ALLOW_PROTOCOL whitelist +test_whitelist () { desc=$1 proto=$2 url=$3 @@ -62,6 +59,129 @@ test_proto () { test_must_fail git clone --bare "$url" tmp.git ) ' + + test_expect_success "clone $desc (env var has precedence)" ' + rm -rf tmp.git && + ( + GIT_ALLOW_PROTOCOL=none && + export GIT_ALLOW_PROTOCOL && + test_must_fail git -c protocol.allow=always clone --bare "$url" tmp.git && + test_must_fail git -c protocol.$proto.allow=always clone --bare "$url" tmp.git + ) + ' +} + +test_config () { + desc=$1 + proto=$2 + url=$3 + + # Test clone/fetch/push with protocol.<type>.allow config + test_expect_success "clone $desc (enabled with config)" ' + rm -rf tmp.git && + git -c protocol.$proto.allow=always clone --bare "$url" tmp.git + ' + + test_expect_success "fetch $desc (enabled)" ' + git -C tmp.git -c protocol.$proto.allow=always fetch + ' + + test_expect_success "push $desc (enabled)" ' + git -C tmp.git -c protocol.$proto.allow=always push origin HEAD:pushed + ' + + test_expect_success "push $desc (disabled)" ' + test_must_fail git -C tmp.git -c protocol.$proto.allow=never push origin HEAD:pushed + ' + + test_expect_success "fetch $desc (disabled)" ' + test_must_fail git -C tmp.git -c protocol.$proto.allow=never fetch + ' + + test_expect_success "clone $desc (disabled)" ' + rm -rf tmp.git && + test_must_fail git -c protocol.$proto.allow=never clone --bare "$url" tmp.git + ' + + # Test clone/fetch/push with protocol.user.allow and its env var + test_expect_success "clone $desc (enabled)" ' + rm -rf tmp.git && + git -c protocol.$proto.allow=user clone --bare "$url" tmp.git + ' + + test_expect_success "fetch $desc (enabled)" ' + git -C tmp.git -c protocol.$proto.allow=user fetch + ' + + test_expect_success "push $desc (enabled)" ' + git -C tmp.git -c protocol.$proto.allow=user push origin HEAD:pushed + ' + + test_expect_success "push $desc (disabled)" ' + ( + cd tmp.git && + GIT_PROTOCOL_FROM_USER=0 && + export GIT_PROTOCOL_FROM_USER && + test_must_fail git -c protocol.$proto.allow=user push origin HEAD:pushed + ) + ' + + test_expect_success "fetch $desc (disabled)" ' + ( + cd tmp.git && + GIT_PROTOCOL_FROM_USER=0 && + export GIT_PROTOCOL_FROM_USER && + test_must_fail git -c protocol.$proto.allow=user fetch + ) + ' + + test_expect_success "clone $desc (disabled)" ' + rm -rf tmp.git && + ( + GIT_PROTOCOL_FROM_USER=0 && + export GIT_PROTOCOL_FROM_USER && + test_must_fail git -c protocol.$proto.allow=user clone --bare "$url" tmp.git + ) + ' + + # Test clone/fetch/push with protocol.allow user defined default + test_expect_success "clone $desc (enabled)" ' + rm -rf tmp.git && + git config --global protocol.allow always && + git clone --bare "$url" tmp.git + ' + + test_expect_success "fetch $desc (enabled)" ' + git -C tmp.git fetch + ' + + test_expect_success "push $desc (enabled)" ' + git -C tmp.git push origin HEAD:pushed + ' + + test_expect_success "push $desc (disabled)" ' + git config --global protocol.allow never && + test_must_fail git -C tmp.git push origin HEAD:pushed + ' + + test_expect_success "fetch $desc (disabled)" ' + test_must_fail git -C tmp.git fetch + ' + + test_expect_success "clone $desc (disabled)" ' + rm -rf tmp.git && + test_must_fail git clone --bare "$url" tmp.git + ' +} + +# test cloning a particular protocol +# $1 - description of the protocol +# $2 - machine-readable name of the protocol +# $3 - the URL to try cloning +test_proto () { + test_whitelist "$@" + + test_config "$@" } # set up an ssh wrapper that will access $host/$repo in the diff --git a/t/t5509-fetch-push-namespaces.sh b/t/t5509-fetch-push-namespaces.sh index bc44ac36d5..75c570adca 100755 --- a/t/t5509-fetch-push-namespaces.sh +++ b/t/t5509-fetch-push-namespaces.sh @@ -4,6 +4,7 @@ test_description='fetch/push involving ref namespaces' . ./test-lib.sh test_expect_success setup ' + git config --global protocol.ext.allow user && test_tick && git init original && ( diff --git a/t/t5802-connect-helper.sh b/t/t5802-connect-helper.sh index b7a7f9d588..c6c2661878 100755 --- a/t/t5802-connect-helper.sh +++ b/t/t5802-connect-helper.sh @@ -4,6 +4,7 @@ test_description='ext::cmd remote "connect" helper' . ./test-lib.sh test_expect_success setup ' + git config --global protocol.ext.allow user && test_tick && git commit --allow-empty -m initial && test_tick && diff --git a/transport.c b/transport.c index dff929ec01..fbd799d062 100644 --- a/transport.c +++ b/transport.c @@ -617,10 +617,81 @@ static const struct string_list *protocol_whitelist(void) return enabled ? &allowed : NULL; } +enum protocol_allow_config { + PROTOCOL_ALLOW_NEVER = 0, + PROTOCOL_ALLOW_USER_ONLY, + PROTOCOL_ALLOW_ALWAYS +}; + +static enum protocol_allow_config parse_protocol_config(const char *key, + const char *value) +{ + if (!strcasecmp(value, "always")) + return PROTOCOL_ALLOW_ALWAYS; + else if (!strcasecmp(value, "never")) + return PROTOCOL_ALLOW_NEVER; + else if (!strcasecmp(value, "user")) + return PROTOCOL_ALLOW_USER_ONLY; + + die("unknown value for config '%s': %s", key, value); +} + +static enum protocol_allow_config get_protocol_config(const char *type) +{ + char *key = xstrfmt("protocol.%s.allow", type); + char *value; + + /* first check the per-protocol config */ + if (!git_config_get_string(key, &value)) { + enum protocol_allow_config ret = + parse_protocol_config(key, value); + free(key); + free(value); + return ret; + } + free(key); + + /* if defined, fallback to user-defined default for unknown protocols */ + if (!git_config_get_string("protocol.allow", &value)) { + enum protocol_allow_config ret = + parse_protocol_config("protocol.allow", value); + free(value); + return ret; + } + + /* fallback to built-in defaults */ + /* known safe */ + if (!strcmp(type, "http") || + !strcmp(type, "https") || + !strcmp(type, "git") || + !strcmp(type, "ssh") || + !strcmp(type, "file")) + return PROTOCOL_ALLOW_ALWAYS; + + /* known scary; err on the side of caution */ + if (!strcmp(type, "ext")) + return PROTOCOL_ALLOW_NEVER; + + /* unknown; by default let them be used only directly by the user */ + return PROTOCOL_ALLOW_USER_ONLY; +} + int is_transport_allowed(const char *type) { - const struct string_list *allowed = protocol_whitelist(); - return !allowed || string_list_has_string(allowed, type); + const struct string_list *whitelist = protocol_whitelist(); + if (whitelist) + return string_list_has_string(whitelist, type); + + switch (get_protocol_config(type)) { + case PROTOCOL_ALLOW_ALWAYS: + return 1; + case PROTOCOL_ALLOW_NEVER: + return 0; + case PROTOCOL_ALLOW_USER_ONLY: + return git_env_bool("GIT_PROTOCOL_FROM_USER", 1); + } + + die("BUG: invalid protocol_allow_config type"); } void transport_check_allowed(const char *type) |