From b480b74192a7c00c4ea077286b921b96e42efabc Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Thu, 11 Apr 2019 06:58:44 +0200 Subject: add identifier sanitation for setting FSM instance ids We often compose FSM instance IDs from context information, for example placing an MSISDN string or IP:port information in the FSM instance id, using osmo_fsm_inst_update_id_f(). This fails if any characters are contained that don't pass osmo_identifier_valid(). Hence it is the task of the caller to make sure only characters allowed in an FSM id are applied. Provide API to trivially allow this by replacing illegal chars: - osmo_identifier_sanitize_buf(), with access to the same set of illegal characters defined in utils.c, - osmo_fsm_inst_update_id_f_sanitize() implicitly replaces non-identifier chars. This makes it easy to add strings like '192.168.0.1:2342' or '+4987654321' to an FSM instance id, without adding string mangling to each place that sets an id; e.g. replacing with '-' to yield '192-168-0-1:2342' or '-4987654321'. Change-Id: Ia40a6f3b2243c95fe428a080b938e11d8ab771a7 --- src/fsm.c | 29 +++++++++++++++++++++++++++++ src/utils.c | 24 ++++++++++++++++++++++-- 2 files changed, 51 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/fsm.c b/src/fsm.c index b6912c6b..c32767b2 100644 --- a/src/fsm.c +++ b/src/fsm.c @@ -364,6 +364,35 @@ int osmo_fsm_inst_update_id_f(struct osmo_fsm_inst *fi, const char *fmt, ...) return 0; } +/*! Change id of the FSM instance using a string format, and ensuring a valid id. + * Replace any characters that are not permitted as FSM identifier with replace_with. + * \param[in] fi FSM instance. + * \param[in] replace_with Character to use instead of non-permitted FSM id characters. + * Make sure to choose a legal character, e.g. '-'. + * \param[in] fmt format string to compose new ID. + * \param[in] ... variable argument list for format string. + * \returns 0 if the ID was updated, otherwise -EINVAL. + */ +int osmo_fsm_inst_update_id_f_sanitize(struct osmo_fsm_inst *fi, char replace_with, const char *fmt, ...) +{ + char *id = NULL; + va_list ap; + int rc; + + if (!fmt) + return osmo_fsm_inst_update_id(fi, NULL); + + va_start(ap, fmt); + id = talloc_vasprintf(fi, fmt, ap); + va_end(ap); + + osmo_identifier_sanitize_buf(id, NULL, replace_with); + + rc = osmo_fsm_inst_update_id(fi, id); + talloc_free(id); + return rc; +} + /*! allocate a new instance of a specified FSM * \param[in] fsm Descriptor of the FSM * \param[in] ctx talloc context from which to allocate memory diff --git a/src/utils.c b/src/utils.c index 6116d3ad..896e9177 100644 --- a/src/utils.c +++ b/src/utils.c @@ -553,6 +553,8 @@ bool osmo_is_hexstr(const char *str, int min_digits, int max_digits, return true; } +static const char osmo_identifier_illegal_chars[] = "., {}[]()<>|~\\^`'\"?=;/+*&%$#!"; + /*! Determine if a given identifier is valid, i.e. doesn't contain illegal chars * \param[in] str String to validate * \param[in] sep_chars Permitted separation characters between identifiers. @@ -561,7 +563,6 @@ bool osmo_is_hexstr(const char *str, int min_digits, int max_digits, bool osmo_separated_identifiers_valid(const char *str, const char *sep_chars) { /* characters that are illegal in names */ - static const char illegal_chars[] = "., {}[]()<>|~\\^`'\"?=;/+*&%$#!"; unsigned int i; size_t len; @@ -578,7 +579,7 @@ bool osmo_separated_identifiers_valid(const char *str, const char *sep_chars) if (!isprint((int)str[i])) return false; /* check for some explicit reserved control characters */ - if (strchr(illegal_chars, str[i])) + if (strchr(osmo_identifier_illegal_chars, str[i])) return false; } @@ -594,6 +595,25 @@ bool osmo_identifier_valid(const char *str) return osmo_separated_identifiers_valid(str, NULL); } +/*! Replace characters in the given string buffer so that it is guaranteed to pass osmo_separated_identifiers_valid(). + * To guarantee passing osmo_separated_identifiers_valid(), replace_with must not itself be an illegal character. If in + * doubt, use '-'. + * \param[inout] str Identifier to sanitize, must be nul terminated and in a writable buffer. + * \param[in] sep_chars Additional characters that are allowed besides osmo_identifier_illegal_chars. + * \param[in] replace_with Replace any illegal characters with this character. + */ +void osmo_identifier_sanitize_buf(char *str, const char *sep_chars, char replace_with) +{ + char *pos; + if (!str) + return; + for (pos = str; *pos; pos++) { + if (strchr(osmo_identifier_illegal_chars, *pos) + || (sep_chars && strchr(sep_chars, *pos))) + *pos = replace_with; + } +} + /*! Like osmo_escape_str_buf2, but with unusual ordering of arguments, and may sometimes return string constants instead * of writing to buf for error cases or empty input. * Most *_buf() functions have the buffer and size as first arguments, here the arguments are last. -- cgit v1.2.3