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Diffstat (limited to 'src/lib/encoding/kvline.c')
| -rw-r--r-- | src/lib/encoding/kvline.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/src/lib/encoding/kvline.c b/src/lib/encoding/kvline.c new file mode 100644 index 0000000000..5b220605d6 --- /dev/null +++ b/src/lib/encoding/kvline.c @@ -0,0 +1,297 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file kvline.c + * + * \brief Manipulating lines of key-value pairs. + **/ + +#include "orconfig.h" + +#include "lib/container/smartlist.h" +#include "lib/encoding/confline.h" +#include "lib/encoding/cstring.h" +#include "lib/encoding/kvline.h" +#include "lib/encoding/qstring.h" +#include "lib/malloc/malloc.h" +#include "lib/string/compat_ctype.h" +#include "lib/string/printf.h" +#include "lib/string/util_string.h" +#include "lib/log/escape.h" +#include "lib/log/util_bug.h" + +#include <stdbool.h> +#include <stddef.h> +#include <string.h> + +/** Return true iff we need to quote and escape the string <b>s</b> to encode + * it. + * + * kvline_can_encode_lines() also uses this (with + * <b>as_keyless_val</b> true) to check whether a key would require + * quoting. + */ +static bool +needs_escape(const char *s, bool as_keyless_val) +{ + if (as_keyless_val && *s == 0) + return true; + /* Keyless values containing '=' need to be escaped. */ + if (as_keyless_val && strchr(s, '=')) + return true; + + for (; *s; ++s) { + if (*s >= 127 || TOR_ISSPACE(*s) || ! TOR_ISPRINT(*s) || + *s == '\'' || *s == '\"') { + return true; + } + } + return false; +} + +/** + * Return true iff the key in <b>line</b> is not set. + **/ +static bool +line_has_no_key(const config_line_t *line) +{ + return line->key == NULL || strlen(line->key) == 0; +} + +/** + * Return true iff the value in <b>line</b> is not set. + **/ +static bool +line_has_no_val(const config_line_t *line) +{ + return line->value == NULL || strlen(line->value) == 0; +} + +/** + * Return true iff the all the lines in <b>line</b> can be encoded + * using <b>flags</b>. + **/ +static bool +kvline_can_encode_lines(const config_line_t *line, unsigned flags) +{ + for ( ; line; line = line->next) { + const bool keyless = line_has_no_key(line); + if (keyless && ! (flags & KV_OMIT_KEYS)) { + /* If KV_OMIT_KEYS is not set, we can't encode a line with no key. */ + return false; + } + + if (needs_escape(line->value, keyless) && ! (flags & (KV_QUOTED|KV_RAW))) { + /* If both KV_QUOTED and KV_RAW are false, we can't encode a + value that needs quotes. */ + return false; + } + if (!keyless && needs_escape(line->key, true)) { + /* We can't handle keys that need quoting. */ + return false; + } + } + return true; +} + +/** + * Encode a linked list of lines in <b>line</b> as a series of 'Key=Value' + * pairs, using the provided <b>flags</b> to encode it. Return a newly + * allocated string on success, or NULL on failure. + * + * If KV_QUOTED is set in <b>flags</b>, then all values that contain + * spaces or unusual characters are escaped and quoted. Otherwise, such + * values are not allowed. Mutually exclusive with KV_RAW. + * + * If KV_OMIT_KEYS is set in <b>flags</b>, then pairs with empty keys are + * allowed, and are encoded as 'Value'. Otherwise, such pairs are not + * allowed. + * + * If KV_OMIT_VALS is set in <b>flags</b>, then an empty value is + * encoded as 'Key', not as 'Key=' or 'Key=""'. Mutually exclusive with + * KV_OMIT_KEYS. + * + * If KV_RAW is set in <b>flags</b>, then don't apply any quoting to + * the value, and assume that the caller has adequately quoted it. + * (The control protocol has some quirks that make this necessary.) + * Mutually exclusive with KV_QUOTED. + * + * KV_QUOTED_QSTRING is not supported. + */ +char * +kvline_encode(const config_line_t *line, + unsigned flags) +{ + tor_assert(! (flags & KV_QUOTED_QSTRING)); + + tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) != + (KV_OMIT_KEYS|KV_OMIT_VALS)); + tor_assert((flags & (KV_QUOTED|KV_RAW)) != (KV_QUOTED|KV_RAW)); + + if (!kvline_can_encode_lines(line, flags)) + return NULL; + + smartlist_t *elements = smartlist_new(); + + for (; line; line = line->next) { + + const char *k = ""; + const char *eq = "="; + const char *v = ""; + const bool keyless = line_has_no_key(line); + bool esc = needs_escape(line->value, keyless); + char *tmp = NULL; + + if (! keyless) { + k = line->key; + } else { + eq = ""; + } + + if ((flags & KV_OMIT_VALS) && line_has_no_val(line)) { + eq = ""; + v = ""; + } else if (!(flags & KV_RAW) && esc) { + tmp = esc_for_log(line->value); + v = tmp; + } else { + v = line->value; + } + + smartlist_add_asprintf(elements, "%s%s%s", k, eq, v); + tor_free(tmp); + } + + char *result = smartlist_join_strings(elements, " ", 0, NULL); + + SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp)); + smartlist_free(elements); + + return result; +} + +/** + * Decode a <b>line</b> containing a series of space-separated 'Key=Value' + * pairs, using the provided <b>flags</b> to decode it. Return a newly + * allocated list of pairs on success, or NULL on failure. + * + * If KV_QUOTED is set in <b>flags</b>, then (double-)quoted values are + * allowed and handled as C strings. Otherwise, such values are not allowed. + * + * If KV_OMIT_KEYS is set in <b>flags</b>, then values without keys are + * allowed. Otherwise, such values are not allowed. + * + * If KV_OMIT_VALS is set in <b>flags</b>, then keys without values are + * allowed. Otherwise, such keys are not allowed. Mutually exclusive with + * KV_OMIT_KEYS. + * + * If KV_QUOTED_QSTRING is set in <b>flags</b>, then double-quoted values + * are allowed and handled as QuotedStrings per qstring.c. Do not add + * new users of this flag. + * + * KV_RAW is not supported. + */ +config_line_t * +kvline_parse(const char *line, unsigned flags) +{ + tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) != + (KV_OMIT_KEYS|KV_OMIT_VALS)); + tor_assert(!(flags & KV_RAW)); + + const char *cp = line, *cplast = NULL; + const bool omit_keys = (flags & KV_OMIT_KEYS) != 0; + const bool omit_vals = (flags & KV_OMIT_VALS) != 0; + const bool quoted = (flags & (KV_QUOTED|KV_QUOTED_QSTRING)) != 0; + const bool c_quoted = (flags & (KV_QUOTED)) != 0; + + config_line_t *result = NULL; + config_line_t **next_line = &result; + + char *key = NULL; + char *val = NULL; + + while (*cp) { + key = val = NULL; + /* skip all spaces */ + { + size_t idx = strspn(cp, " \t\r\v\n"); + cp += idx; + } + if (BUG(cp == cplast)) { + /* If we didn't parse anything since the last loop, this code is + * broken. */ + goto err; // LCOV_EXCL_LINE + } + cplast = cp; + if (! *cp) + break; /* End of string; we're done. */ + + /* Possible formats are K=V, K="V", K, V, and "V", depending on flags. */ + + /* Find where the key ends */ + if (*cp != '\"') { + size_t idx = strcspn(cp, " \t\r\v\n="); + + if (cp[idx] == '=') { + key = tor_memdup_nulterm(cp, idx); + cp += idx + 1; + } else if (omit_vals) { + key = tor_memdup_nulterm(cp, idx); + cp += idx; + goto commit; + } else { + if (!omit_keys) + goto err; + } + } + + if (*cp == '\"') { + /* The type is "V". */ + if (!quoted) + goto err; + size_t len=0; + if (c_quoted) { + cp = unescape_string(cp, &val, &len); + } else { + cp = decode_qstring(cp, strlen(cp), &val, &len); + } + if (cp == NULL || len != strlen(val)) { + // The string contains a NUL or is badly coded. + goto err; + } + } else { + size_t idx = strcspn(cp, " \t\r\v\n"); + val = tor_memdup_nulterm(cp, idx); + cp += idx; + } + + commit: + if (key && strlen(key) == 0) { + /* We don't allow empty keys. */ + goto err; + } + + *next_line = tor_malloc_zero(sizeof(config_line_t)); + (*next_line)->key = key ? key : tor_strdup(""); + (*next_line)->value = val ? val : tor_strdup(""); + next_line = &(*next_line)->next; + key = val = NULL; + } + + if (! (flags & KV_QUOTED_QSTRING)) { + if (!kvline_can_encode_lines(result, flags)) { + goto err; + } + } + return result; + + err: + tor_free(key); + tor_free(val); + config_free_lines(result); + return NULL; +} |