commit ba05324242aebdbf646ebb8e8f3aaef45b1f29ec Author: Nick Mathewson nickm@torproject.org Date: Tue Apr 9 09:42:51 2019 -0400

Move and rename decode_escaped_string()

This function decodes something different from the usual c-escaped format.

It is only used in controller authorization. --- src/feature/control/control_auth.c | 7 +-- src/feature/control/control_fmt.c | 74 ------------------------------- src/feature/control/control_fmt.h | 2 - src/lib/encoding/include.am | 2 + src/lib/encoding/qstring.c | 90 ++++++++++++++++++++++++++++++++++++++ src/lib/encoding/qstring.h | 18 ++++++++ 6 files changed, 114 insertions(+), 79 deletions(-)

diff --git a/src/feature/control/control_auth.c b/src/feature/control/control_auth.c index 927115a30..820429048 100644 --- a/src/feature/control/control_auth.c +++ b/src/feature/control/control_auth.c @@ -17,6 +17,7 @@ #include "lib/crypt_ops/crypto_rand.h" #include "lib/crypt_ops/crypto_util.h" #include "lib/encoding/confline.h" +#include "lib/encoding/qstring.h"

#include "lib/crypt_ops/crypto_s2k.h"

@@ -149,8 +150,8 @@ handle_control_authchallenge(control_connection_t *conn, uint32_t len, cp += strspn(cp, " \t\n\r"); if (*cp == '"') { const char *newcp = - decode_escaped_string(cp, len - (cp - body), - &client_nonce, &client_nonce_len); + decode_qstring(cp, len - (cp - body), + &client_nonce, &client_nonce_len); if (newcp == NULL) { connection_write_str_to_buf("513 Invalid quoted client nonce\r\n", conn); @@ -275,7 +276,7 @@ handle_control_authenticate(control_connection_t *conn, uint32_t len, return 0; } } else { - if (!decode_escaped_string(body, len, &password, &password_len)) { + if (!decode_qstring(body, len, &password, &password_len)) { connection_write_str_to_buf("551 Invalid quoted string. You need " "to put the password in double quotes.\r\n", conn); connection_mark_for_close(TO_CONN(conn)); diff --git a/src/feature/control/control_fmt.c b/src/feature/control/control_fmt.c index 427f4288f..b2ab4f10b 100644 --- a/src/feature/control/control_fmt.c +++ b/src/feature/control/control_fmt.c @@ -305,80 +305,6 @@ send_control_done(control_connection_t *conn) connection_write_str_to_buf("250 OK\r\n", conn); }

-/** If the first <b>in_len_max</b> characters in <b>start</b> contain a - * double-quoted string with escaped characters, return the length of that - * string (as encoded, including quotes). Otherwise return -1. */ -static inline int -get_escaped_string_length(const char *start, size_t in_len_max, - int *chars_out) -{ - const char *cp, *end; - int chars = 0; - - if (*start != '"') - return -1; - - cp = start+1; - end = start+in_len_max; - - /* Calculate length. */ - while (1) { - if (cp >= end) { - return -1; /* Too long. */ - } else if (*cp == '\') { - if (++cp == end) - return -1; /* Can't escape EOS. */ - ++cp; - ++chars; - } else if (*cp == '"') { - break; - } else { - ++cp; - ++chars; - } - } - if (chars_out) - *chars_out = chars; - return (int)(cp - start+1); -} - -/** Given a pointer to a string starting at <b>start</b> containing - * <b>in_len_max</b> characters, decode a string beginning with one double - * quote, containing any number of non-quote characters or characters escaped - * with a backslash, and ending with a final double quote. Place the resulting - * string (unquoted, unescaped) into a newly allocated string in *<b>out</b>; - * store its length in <b>out_len</b>. On success, return a pointer to the - * character immediately following the escaped string. On failure, return - * NULL. */ -const char * -decode_escaped_string(const char *start, size_t in_len_max, - char **out, size_t *out_len) -{ - const char *cp, *end; - char *outp; - int len, n_chars = 0; - - len = get_escaped_string_length(start, in_len_max, &n_chars); - if (len<0) - return NULL; - - end = start+len-1; /* Index of last quote. */ - tor_assert(*end == '"'); - outp = *out = tor_malloc(len+1); - *out_len = n_chars; - - cp = start+1; - while (cp < end) { - if (*cp == '\') - ++cp; - *outp++ = *cp++; - } - *outp = '\0'; - tor_assert((outp - *out) == (int)*out_len); - - return end+1; -} - /** Return a longname the node whose identity is <b>id_digest</b>. If * node_get_by_id() returns NULL, base 16 encoding of <b>id_digest</b> is * returned instead. diff --git a/src/feature/control/control_fmt.h b/src/feature/control/control_fmt.h index 08acf8518..8bbbaa95d 100644 --- a/src/feature/control/control_fmt.h +++ b/src/feature/control/control_fmt.h @@ -25,8 +25,6 @@ char *circuit_describe_status_for_controller(origin_circuit_t *circ);

size_t write_escaped_data(const char *data, size_t len, char **out); size_t read_escaped_data(const char *data, size_t len, char **out); -const char *decode_escaped_string(const char *start, size_t in_len_max, - char **out, size_t *out_len); void send_control_done(control_connection_t *conn);

MOCK_DECL(const char *, node_describe_longname_by_id,(const char *id_digest)); diff --git a/src/lib/encoding/include.am b/src/lib/encoding/include.am index 83e9211b6..8272e4e5f 100644 --- a/src/lib/encoding/include.am +++ b/src/lib/encoding/include.am @@ -11,6 +11,7 @@ src_lib_libtor_encoding_a_SOURCES = \ src/lib/encoding/keyval.c \ src/lib/encoding/kvline.c \ src/lib/encoding/pem.c \ + src/lib/encoding/qstring.c \ src/lib/encoding/time_fmt.c

src_lib_libtor_encoding_testing_a_SOURCES = \ @@ -25,4 +26,5 @@ noinst_HEADERS += \ src/lib/encoding/keyval.h \ src/lib/encoding/kvline.h \ src/lib/encoding/pem.h \ + src/lib/encoding/qstring.h \ src/lib/encoding/time_fmt.h diff --git a/src/lib/encoding/qstring.c b/src/lib/encoding/qstring.c new file mode 100644 index 000000000..a92d28c70 --- /dev/null +++ b/src/lib/encoding/qstring.c @@ -0,0 +1,90 @@ +/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file qstring.c + * \brief Implement QuotedString parsing. + * + * Note that this is only used for controller authentication; do not + * create new users for this. Instead, prefer the cstring.c functions. + **/ + +#include "orconfig.h" +#include "lib/encoding/qstring.h" +#include "lib/malloc/malloc.h" +#include "lib/log/util_bug.h" + +/** If the first <b>in_len_max</b> characters in <b>start</b> contain a + * QuotedString, return the length of that + * string (as encoded, including quotes). Otherwise return -1. */ +static inline int +get_qstring_length(const char *start, size_t in_len_max, + int *chars_out) +{ + const char *cp, *end; + int chars = 0; + + if (*start != '"') + return -1; + + cp = start+1; + end = start+in_len_max; + + /* Calculate length. */ + while (1) { + if (cp >= end) { + return -1; /* Too long. */ + } else if (*cp == '\') { + if (++cp == end) + return -1; /* Can't escape EOS. */ + ++cp; + ++chars; + } else if (*cp == '"') { + break; + } else { + ++cp; + ++chars; + } + } + if (chars_out) + *chars_out = chars; + return (int)(cp - start+1); +} + +/** Given a pointer to a string starting at <b>start</b> containing + * <b>in_len_max</b> characters, decode a string beginning with one double + * quote, containing any number of non-quote characters or characters escaped + * with a backslash, and ending with a final double quote. Place the resulting + * string (unquoted, unescaped) into a newly allocated string in *<b>out</b>; + * store its length in <b>out_len</b>. On success, return a pointer to the + * character immediately following the escaped string. On failure, return + * NULL. */ +const char * +decode_qstring(const char *start, size_t in_len_max, + char **out, size_t *out_len) +{ + const char *cp, *end; + char *outp; + int len, n_chars = 0; + + len = get_qstring_length(start, in_len_max, &n_chars); + if (len<0) + return NULL; + + end = start+len-1; /* Index of last quote. */ + tor_assert(*end == '"'); + outp = *out = tor_malloc(len+1); + *out_len = n_chars; + + cp = start+1; + while (cp < end) { + if (*cp == '\') + ++cp; + *outp++ = *cp++; + } + *outp = '\0'; + tor_assert((outp - *out) == (int)*out_len); + + return end+1; +} diff --git a/src/lib/encoding/qstring.h b/src/lib/encoding/qstring.h new file mode 100644 index 000000000..fe15b655f --- /dev/null +++ b/src/lib/encoding/qstring.h @@ -0,0 +1,18 @@ +/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file qstring.h + * \brief Header for qstring.c + */ + +#ifndef TOR_ENCODING_QSTRING_H +#define TOR_ENCODING_QSTRING_H + +#include <stddef.h> + +const char *decode_qstring(const char *start, size_t in_len_max, + char **out, size_t *out_len); + +#endif