[Libguestfs] [nbdkit PATCH v2 1/2] common/utils: Add uri_quote and tests

Normally, when using captive mode --run coupled with a Unix socket, the user is using -U -, and we get lucky that the typcial values of $TMPDIR plus our use of mktemp produce a name that needs neither shell quoting nor which requires %-encoding for use in a URI. But a determined user can use an explicit -U /odd/#path or setting of $TMPDIR that gets correctly shell-quoted, but which would break interpretation in a URI parser. In preparation for adding a $uri variable under --run, it's time to ensure that we can always produce a valid unambiguous URI by adding a new helper function. It is intentional that uri_quote of an empty string produces no output, as the intended audience of uri_quote is always a smaller component within a larger URI (different from shell_quote which does have use on a stand-alone empty string). It's also worth testing the existing shell_quote (including the bug fixed in bdda3f30) as well as the new uri_quote. The test includes an XXX comment that matches the counterpart XXX in shell_quote(); an audit of shell_quote() callers shows that the iso plugin might be affected if someone ever used prog=a=b, but that is fringe enough to put off to another day. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- common/utils/utils.h | 1 + common/utils/test-quotes.c | 108 +++++++++++++++++++++++++++++++++++++ common/utils/utils.c | 27 ++++++++++ .gitignore | 1 + common/utils/Makefile.am | 11 ++++ 5 files changed, 148 insertions(+) create mode 100644 common/utils/test-quotes.c diff --git a/common/utils/utils.h b/common/utils/utils.h index 4d1abf03..3f10cdc0 100644 --- a/common/utils/utils.h +++ b/common/utils/utils.h @@ -34,6 +34,7 @@ #define NBDKIT_UTILS_H extern void shell_quote (const char *str, FILE *fp); +extern void uri_quote (const char *str, FILE *fp); extern int exit_status_to_nbd_error (int status, const char *cmd); #endif /* NBDKIT_UTILS_H */ diff --git a/common/utils/test-quotes.c b/common/utils/test-quotes.c new file mode 100644 index 00000000..33b8299e --- /dev/null +++ b/common/utils/test-quotes.c @@ -0,0 +1,108 @@ +/* nbdkit + * Copyright (C) 2019 Red Hat Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * * Neither the name of Red Hat nor the names of its contributors may be + * used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* Unit tests of utils quoting code. */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> +#include <stdbool.h> + +#include "utils.h" + +static bool +test (const char *orig, const char *fnname, void (*fn) (const char *, FILE *), + const char *exp) +{ + char *str = NULL; + size_t str_len = 0; + FILE *fp; + + fp = open_memstream (&str, &str_len); + assert (fp); + fn (orig, fp); + if (fclose (fp) == EOF) + assert (false); + if (str_len == 0 && !str) + str = strdup (""); + assert (str); + + if (strcmp (str, exp)) { + fprintf (stderr, "%s failed, got '%s' expected '%s'\n", + fnname, str, exp); + free (str); + return true; + } + free (str); + return false; +} + +int +main (void) +{ + struct { + const char *orig; + const char *shell; + const char *uri; + } tests[] = { + { "a-b_c.0", "a-b_c.0", "a-b_c.0" }, + { "/Safe/Path", "/Safe/Path", "/Safe/Path" }, + { "a~b", "\"a~b\"", "a~b" }, + { "", "\"\"", "" }, + { "a=b", "a=b", "a%3Db" }, /* XXX shell wrong if used as argv[0] */ + { "a;b", "\"a;b\"", "a%3Bb" }, + { "a b", "\"a b\"", "a%20b" }, + { "a%b", "\"a%b\"", "a%25b" }, + { "a'b\"c$d`e\\f", "\"a'b\\\"c\\$d\\`e\\\\f\"", "a%27b%22c%24d%60e%5Cf" }, + }; + size_t i; + bool fail = false; + + for (i = 0; i < sizeof tests / sizeof tests[0]; i++) { + fail |= test (tests[i].orig, "shell_quote", shell_quote, tests[i].shell); + fail |= test (tests[i].orig, "uri_quote", uri_quote, tests[i].uri); + } + return fail ? EXIT_FAILURE : EXIT_SUCCESS; +} + +/* Unrelated utils code uses nbdkit_error, normally provided by the main + * server program. So we have to provide it here. + */ +void +nbdkit_error (const char *fs, ...) +{ + /* XXX split utils.c to avoid needing this linker stub? */ + assert (false); +} diff --git a/common/utils/utils.c b/common/utils/utils.c index 7a584e25..7534a13d 100644 --- a/common/utils/utils.c +++ b/common/utils/utils.c @@ -75,6 +75,33 @@ shell_quote (const char *str, FILE *fp) fputc ('"', fp); } +/* Print str to fp, URI quoting if necessary. + * The resulting string is safe for use in a URI path or query component, + * and can be passed through the shell without further quoting. + */ +void +uri_quote (const char *str, FILE *fp) +{ + /* safe_chars contains the RFC 3986 unreserved characters plus '/'. */ + const char *safe_chars = + "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.-_~/"; + size_t i, len; + + /* If the string consists only of safe characters, output it as-is. */ + len = strlen (str); + if (len == strspn (str, safe_chars)) { + fputs (str, fp); + return; + } + + for (i = 0; i < len; ++i) { + if (strchr (safe_chars, str[i])) + fputc (str[i], fp); + else + fprintf (fp, "%%%02X", str[i] & 0xff); + } +} + /* Convert exit status to nbd_error. If the exit status was nonzero * or another failure then -1 is returned. */ diff --git a/.gitignore b/.gitignore index 3770d3ba..46ab5dc6 100644 --- a/.gitignore +++ b/.gitignore @@ -35,6 +35,7 @@ Makefile.in /common/include/test-random /common/include/test-tvdiff /common/protocol/protostrings.c +/common/utils/test-quotes /compile /config.guess /config.h diff --git a/common/utils/Makefile.am b/common/utils/Makefile.am index f4f17005..cc364300 100644 --- a/common/utils/Makefile.am +++ b/common/utils/Makefile.am @@ -43,3 +43,14 @@ libutils_la_CPPFLAGS = \ -I$(top_srcdir)/include libutils_la_CFLAGS = \ $(WARNINGS_CFLAGS) + +# Unit tests. + +TESTS = test-quotes +check_PROGRAMS = test-quotes + +test_quotes_SOURCES = test-quotes.c utils.c utils.h +test_quotes_CPPFLAGS = \ + -I$(top_srcdir)/common/utils +test_quotes_CFLAGS = \ + $(WARNINGS_CFLAGS) -- 2.20.1