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| author | Bryce Kwon <bryce@brycekwon.com> | |
|---|---|---|
| committer | Bryce Kwon <bryce@brycekwon.com> | |
| commit | ||
| parent | ||
| tree | ||
| download | ||
Serve only the files a dumb clone asks for
The object path check let any run of safe characters through, so a
spelling such as info//alternates or info/./alternates reached the
alternates file the exact name was refused for.
| -rw-r--r-- | source/ui-clone.c | 37 | |
| -rwxr-xr-x | tests/t0301-security.sh | 4 | |
| -rwxr-xr-x | tests/t0303-robustness.sh | 10 |
3 files changed, 30 insertions, 21 deletions
diff --git a/source/ui-clone.c b/source/ui-clone.c index 610aaa6..dad21d5 100644 --- a/source/ui-clone.c +++ b/source/ui-clone.c @@ -79,20 +79,31 @@ static void print_pack_info(void) } } +static size_t hex_span(const char *s) +{ + return strspn(s, "0123456789abcdef"); +} + /* - * Only the characters an object path can hold pass, and no dotdot component. + * A dumb client asks for three shapes of file below objects: a loose object + * at xx/rest-of-hex, a pack or its index at pack/pack-hex.pack or .idx, and + * info/http-alternates. Nothing else is served, so no spelling of a path can + * reach a file outside those, the alternates file among them. */ -static int path_is_safe(const char *path) +static int object_path_is_served(const char *path) { - const char *p; + const size_t hexsz = the_hash_algo->hexsz; + const char *rest; - for (p = path; *p; ++p) { - if (*p == '.' && *(p + 1) == '.') - return 0; - if (!isalnum((unsigned char)*p) && *p != '/' && *p != '.' && *p != '-') - return 0; + if (!strcmp(path, "info/http-alternates")) + return 1; + if (skip_prefix(path, "pack/pack-", &rest)) { + size_t n = hex_span(rest); + + return n == hexsz && (!strcmp(rest + n, ".pack") || !strcmp(rest + n, ".idx")); } - return 1; + return hex_span(path) == 2 && path[2] == '/' && hex_span(path + 3) == hexsz - 2 && + path[hexsz + 1] == '\0'; } /* @@ -166,17 +177,11 @@ void cgit_clone_objects(void) return; } - // The alternates file names directories on the server's disk, which a - // client fetching over http cannot reach, so only the http form that - // is written for such clients goes out. - if (!strcmp(ctx.qry.path, "info/alternates")) { + if (!object_path_is_served(ctx.qry.path)) { cgit_print_error_page(404, "Not Found", "Not found"); return; } - if (!path_is_safe(ctx.qry.path)) - goto err; - path = repo_git_path(the_repository, "objects/%s", ctx.qry.path); send_file(path); free(path); diff --git a/tests/t0301-security.sh b/tests/t0301-security.sh index 3df2cee..d9ec265 100755 --- a/tests/t0301-security.sh +++ b/tests/t0301-security.sh @@ -452,10 +452,10 @@ test_expect_success 'a posted length past any buffer is clamped' ' test_expect_success 'the dumb transport refuses a path that climbs out' ' cveq "url=cve/objects/../config" >tmp && - grep "^Status: 400" tmp && + grep "^Status: 404" tmp && ! grep "repositoryformatversion" tmp && cveq "url=cve/objects/info/../../config" >tmp && - grep "^Status: 400" tmp && + grep "^Status: 404" tmp && ! grep "repositoryformatversion" tmp ' diff --git a/tests/t0303-robustness.sh b/tests/t0303-robustness.sh index ecd6129..f2f8572 100755 --- a/tests/t0303-robustness.sh +++ b/tests/t0303-robustness.sh @@ -592,9 +592,13 @@ test_expect_success 'the dumb transport sends a file with its size' ' test_expect_success 'the dumb transport withholds the alternates file' ' mkdir -p repos/rob/.git/objects/info && echo "$PWD/repos/foo/.git/objects" >repos/rob/.git/objects/info/alternates && - robq "url=rob/objects/info/alternates" >tmp && - grep "^Status: 404" tmp && - ! grep "repos/foo" tmp && + for path in info/alternates info//alternates info/./alternates ./info/alternates \ + info/Alternates /info/alternates + do + robq "url=rob/objects/$path" >tmp && + grep "^Status: 404" tmp && + ! grep "repos/foo" tmp || return 1 + done && rm repos/rob/.git/objects/info/alternates && robq "url=rob/objects/info/packs" >tmp && grep "^Status: 200" tmp |