diff options
author | Taylor Blau <me@ttaylorr.com> | 2023-01-25 22:58:38 +0300 |
---|---|---|
committer | Johannes Schindelin <johannes.schindelin@gmx.de> | 2023-02-06 11:09:14 +0300 |
commit | 2c9a4c731010685b86559c06637aeef2ac5ea06e (patch) | |
tree | 94ef671b634c0516c9643aa5e685ca31c0793453 | |
parent | 0227130244c007870c106fc613903d078730e45c (diff) | |
parent | bffc762f87ae8d18c6001bf0044a76004245754c (diff) |
Merge branch 'tb/clone-local-symlinks' into maint-2.30
Resolve a security vulnerability (CVE-2023-22490) where `clone_local()`
is used in conjunction with non-local transports, leading to arbitrary
path exfiltration.
* tb/clone-local-symlinks:
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
-rw-r--r-- | builtin/clone.c | 8 | ||||
-rw-r--r-- | dir-iterator.c | 13 | ||||
-rw-r--r-- | dir-iterator.h | 5 | ||||
-rwxr-xr-x | t/t0066-dir-iterator.sh | 27 | ||||
-rwxr-xr-x | t/t5604-clone-reference.sh | 16 | ||||
-rwxr-xr-x | t/t5619-clone-local-ambiguous-transport.sh | 70 |
6 files changed, 130 insertions, 9 deletions
diff --git a/builtin/clone.c b/builtin/clone.c index e626073b1f..c042b2e256 100644 --- a/builtin/clone.c +++ b/builtin/clone.c @@ -1201,10 +1201,6 @@ int cmd_clone(int argc, const char **argv, const char *prefix) refspec_appendf(&remote->fetch, "+%s*:%s*", src_ref_prefix, branch_top.buf); - transport = transport_get(remote, remote->url[0]); - transport_set_verbosity(transport, option_verbosity, option_progress); - transport->family = family; - path = get_repo_path(remote->url[0], &is_bundle); is_local = option_local != 0 && path && !is_bundle; if (is_local) { @@ -1224,6 +1220,10 @@ int cmd_clone(int argc, const char **argv, const char *prefix) } if (option_local > 0 && !is_local) warning(_("--local is ignored")); + + transport = transport_get(remote, path ? path : remote->url[0]); + transport_set_verbosity(transport, option_verbosity, option_progress); + transport->family = family; transport->cloning = 1; transport_set_option(transport, TRANS_OPT_KEEP, "yes"); diff --git a/dir-iterator.c b/dir-iterator.c index b17e9f970a..3764dd81a1 100644 --- a/dir-iterator.c +++ b/dir-iterator.c @@ -203,7 +203,7 @@ struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags) { struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter)); struct dir_iterator *dir_iterator = &iter->base; - int saved_errno; + int saved_errno, err; strbuf_init(&iter->base.path, PATH_MAX); strbuf_addstr(&iter->base.path, path); @@ -213,10 +213,15 @@ struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags) iter->flags = flags; /* - * Note: stat already checks for NULL or empty strings and - * inexistent paths. + * Note: stat/lstat already checks for NULL or empty strings and + * nonexistent paths. */ - if (stat(iter->base.path.buf, &iter->base.st) < 0) { + if (iter->flags & DIR_ITERATOR_FOLLOW_SYMLINKS) + err = stat(iter->base.path.buf, &iter->base.st); + else + err = lstat(iter->base.path.buf, &iter->base.st); + + if (err < 0) { saved_errno = errno; goto error_out; } diff --git a/dir-iterator.h b/dir-iterator.h index 08229157c6..e3b6ff2800 100644 --- a/dir-iterator.h +++ b/dir-iterator.h @@ -61,6 +61,11 @@ * not the symlinks themselves, which is the default behavior. Broken * symlinks are ignored. * + * Note: setting DIR_ITERATOR_FOLLOW_SYMLINKS affects resolving the + * starting path as well (e.g., attempting to iterate starting at a + * symbolic link pointing to a directory without FOLLOW_SYMLINKS will + * result in an error). + * * Warning: circular symlinks are also followed when * DIR_ITERATOR_FOLLOW_SYMLINKS is set. The iteration may end up with * an ELOOP if they happen and DIR_ITERATOR_PEDANTIC is set. diff --git a/t/t0066-dir-iterator.sh b/t/t0066-dir-iterator.sh index 92910e4e6c..c826f60f6d 100755 --- a/t/t0066-dir-iterator.sh +++ b/t/t0066-dir-iterator.sh @@ -109,7 +109,9 @@ test_expect_success SYMLINKS 'setup dirs with symlinks' ' mkdir -p dir5/a/c && ln -s ../c dir5/a/b/d && ln -s ../ dir5/a/b/e && - ln -s ../../ dir5/a/b/f + ln -s ../../ dir5/a/b/f && + + ln -s dir4 dir6 ' test_expect_success SYMLINKS 'dir-iterator should not follow symlinks by default' ' @@ -145,4 +147,27 @@ test_expect_success SYMLINKS 'dir-iterator should follow symlinks w/ follow flag test_cmp expected-follow-sorted-output actual-follow-sorted-output ' +test_expect_success SYMLINKS 'dir-iterator does not resolve top-level symlinks' ' + test_must_fail test-tool dir-iterator ./dir6 >out && + + grep "ENOTDIR" out +' + +test_expect_success SYMLINKS 'dir-iterator resolves top-level symlinks w/ follow flag' ' + cat >expected-follow-sorted-output <<-EOF && + [d] (a) [a] ./dir6/a + [d] (a/f) [f] ./dir6/a/f + [d] (a/f/c) [c] ./dir6/a/f/c + [d] (b) [b] ./dir6/b + [d] (b/c) [c] ./dir6/b/c + [f] (a/d) [d] ./dir6/a/d + [f] (a/e) [e] ./dir6/a/e + EOF + + test-tool dir-iterator --follow-symlinks ./dir6 >out && + sort out >actual-follow-sorted-output && + + test_cmp expected-follow-sorted-output actual-follow-sorted-output +' + test_done diff --git a/t/t5604-clone-reference.sh b/t/t5604-clone-reference.sh index 9d32f1c4a4..4ff21d7ccf 100755 --- a/t/t5604-clone-reference.sh +++ b/t/t5604-clone-reference.sh @@ -341,4 +341,20 @@ test_expect_success SYMLINKS 'clone repo with symlinked or unknown files at obje test_must_be_empty T--shared.objects-symlinks.raw ' +test_expect_success SYMLINKS 'clone repo with symlinked objects directory' ' + test_when_finished "rm -fr sensitive malicious" && + + mkdir -p sensitive && + echo "secret" >sensitive/file && + + git init malicious && + rm -fr malicious/.git/objects && + ln -s "$(pwd)/sensitive" ./malicious/.git/objects && + + test_must_fail git clone --local malicious clone 2>err && + + test_path_is_missing clone && + grep "failed to start iterator over" err +' + test_done diff --git a/t/t5619-clone-local-ambiguous-transport.sh b/t/t5619-clone-local-ambiguous-transport.sh new file mode 100755 index 0000000000..cce62bf78d --- /dev/null +++ b/t/t5619-clone-local-ambiguous-transport.sh @@ -0,0 +1,70 @@ +#!/bin/sh + +test_description='test local clone with ambiguous transport' + +. ./test-lib.sh +. "$TEST_DIRECTORY/lib-httpd.sh" + +if ! test_have_prereq SYMLINKS +then + skip_all='skipping test, symlink support unavailable' + test_done +fi + +start_httpd + +REPO="$HTTPD_DOCUMENT_ROOT_PATH/sub.git" +URI="$HTTPD_URL/dumb/sub.git" + +test_expect_success 'setup' ' + mkdir -p sensitive && + echo "secret" >sensitive/secret && + + git init --bare "$REPO" && + test_commit_bulk -C "$REPO" --ref=main 1 && + + git -C "$REPO" update-ref HEAD main && + git -C "$REPO" update-server-info && + + git init malicious && + ( + cd malicious && + + git submodule add "$URI" && + + mkdir -p repo/refs && + touch repo/refs/.gitkeep && + printf "ref: refs/heads/a" >repo/HEAD && + ln -s "$(cd .. && pwd)/sensitive" repo/objects && + + mkdir -p "$HTTPD_URL/dumb" && + ln -s "../../../.git/modules/sub/../../../repo/" "$URI" && + + git add . && + git commit -m "initial commit" + ) && + + # Delete all of the references in our malicious submodule to + # avoid the client attempting to checkout any objects (which + # will be missing, and thus will cause the clone to fail before + # we can trigger the exploit). + git -C "$REPO" for-each-ref --format="delete %(refname)" >in && + git -C "$REPO" update-ref --stdin <in && + git -C "$REPO" update-server-info +' + +test_expect_success 'ambiguous transport does not lead to arbitrary file-inclusion' ' + git clone malicious clone && + test_must_fail git -C clone submodule update --init 2>err && + + test_path_is_missing clone/.git/modules/sub/objects/secret && + # We would actually expect "transport .file. not allowed" here, + # but due to quirks of the URL detection in Git, we mis-parse + # the absolute path as a bogus URL and die before that step. + # + # This works for now, and if we ever fix the URL detection, it + # is OK to change this to detect the transport error. + grep "protocol .* is not supported" err +' + +test_done |