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libbsnmp: make snmp_parse_server() more robust when lacking info
Per documentation snmp_parse_server() has all 4 components optional. We want inputs like "udp::", "udp6::", "stream::" work with local default sockets and even degenerate case of "" shall end with defaults instead of a failure. While here make the parser more robust. Make all parser helpers to behave the same way: on successful return they are responsible to update both start & end of matched substring and return next characater to parse. This eliminates special handling of IPv6 and port parser that used to need to skip a character, and thus eliminates unchecked step forward in snmp_parse_server() itself. Additionally: - use strchr(3) instead of own cycle - INET_ADDRSTRLEN includes space for NUL character - INET6_ADDRSTRLEN includes both the scope and NUL character - prefer sizeof() comparison instead of preprocessor define repetitive use Reviewed by: harti Differential Revision: https://reviews.freebsd.org/D51072
This commit is contained in:
Gleb Smirnoff
parent
777123969d
commit
9ba51cce8b
1 changed files with 87 additions and 100 deletions
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@ -1942,70 +1942,64 @@ get_transp(struct snmp_client *sc, const char **strp)
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* community strings are legal.
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*
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* \param sc client struct to set errors
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* \param strp possible start of community; updated to the point to
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* the next character to parse
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* \param comm possible start of community; updated to start & end
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*
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* \return end of community; equals *strp if there is none; NULL if there
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* was an error
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* \return the next character to parse; NULL if there was an error
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*/
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static inline const char *
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get_comm(struct snmp_client *sc, const char **strp)
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get_comm(struct snmp_client *sc, const char *comm[2])
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{
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const char *p = strrchr(*strp, '@');
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const char *p = strrchr(comm[0], '@');
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if (p == NULL)
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/* no community string */
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return (*strp);
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return (comm[1] = comm[0]);
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if (p - *strp > SNMP_COMMUNITY_MAXLEN) {
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if (p - comm[0] > SNMP_COMMUNITY_MAXLEN) {
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seterr(sc, "community string too long '%.*s'",
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p - *strp, *strp);
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p - comm[0], comm[0]);
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return (NULL);
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}
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*strp = p + 1;
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return (p);
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return ((comm[1] = p) + 1);
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}
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/**
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* Try to get an IPv6 address. This starts with an [ and should end with an ]
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* and everything between should be not longer than INET6_ADDRSTRLEN and
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* parseable by inet_pton().
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* parseable by getaddrinfo().
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*
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* \param sc client struct to set errors
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* \param strp possible start of IPv6 address (the '['); updated to point to
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* the next character to parse (the one after the closing ']')
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* \param ipv6 possible start of IPv6 address (the '['); updated to actual
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* start (one after '[') and actual end (the '[' itself)
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*
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* \return end of address (equals *strp + 1 if there is none) or NULL
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* on errors
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* \return the next character to parse (the one after the closing ']')
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* or NULL on errors
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*/
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static inline const char *
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get_ipv6(struct snmp_client *sc, const char **strp)
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get_ipv6(struct snmp_client *sc, const char *ipv6[2])
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{
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char str[INET6_ADDRSTRLEN + IF_NAMESIZE];
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char str[INET6_ADDRSTRLEN];
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const char *p;
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struct addrinfo hints, *res;
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int error;
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if (**strp != '[')
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return (*strp + 1);
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if (ipv6[0][0] != '[')
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return (ipv6[1] = ipv6[0]);
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const char *p = *strp + 1;
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while (*p != ']' ) {
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if (*p == '\0') {
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seterr(sc, "unterminated IPv6 address '%.*s'",
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p - *strp, *strp);
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return (NULL);
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}
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p++;
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}
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if (p - *strp > INET6_ADDRSTRLEN + IF_NAMESIZE) {
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seterr(sc, "IPv6 address too long '%.*s'", p - *strp, *strp);
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if ((p = strchr(++(ipv6[0]), ']')) == NULL) {
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seterr(sc, "unterminated IPv6 address '%s'", ipv6[0]);
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return (NULL);
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}
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strncpy(str, *strp + 1, p - (*strp + 1));
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str[p - (*strp + 1)] = '\0';
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if ((size_t)(p - ipv6[0]) >= sizeof(str)) {
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seterr(sc, "IPv6 address too long '%.*s'",
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p - ipv6[0], ipv6[0]);
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return (NULL);
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}
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strncpy(str, ipv6[0], p - ipv6[0]);
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str[p - ipv6[0]] = '\0';
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memset(&hints, 0, sizeof(hints));
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hints.ai_flags = AI_CANONNAME | AI_NUMERICHOST;
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@ -2018,8 +2012,7 @@ get_ipv6(struct snmp_client *sc, const char **strp)
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return (NULL);
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}
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freeaddrinfo(res);
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*strp = p + 1;
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return (p);
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return ((ipv6[1] = p) + 1);
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}
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/**
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@ -2028,30 +2021,29 @@ get_ipv6(struct snmp_client *sc, const char **strp)
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* inet_aton().
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*
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* \param sc client struct to set errors
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* \param strp possible start of IPv4 address; updated to point to the
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* next character to parse
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* \param ipv4 possible start of IPv4 address; updated to start & end
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*
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* \return end of address (equals *strp if there is none) or NULL
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* on errors
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* \return the next character to parse; or NULL on errors
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*/
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static inline const char *
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get_ipv4(struct snmp_client *sc, const char **strp)
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get_ipv4(struct snmp_client *sc, const char *ipv4[2])
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{
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const char *p = *strp;
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char str[INET_ADDRSTRLEN];
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const char *p = ipv4[0];
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while (isascii(*p) && (isdigit(*p) || *p == '.'))
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p++;
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if (p - *strp > INET_ADDRSTRLEN) {
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seterr(sc, "IPv4 address too long '%.*s'", p - *strp, *strp);
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if ((size_t)(p - ipv4[0]) >= sizeof(str)) {
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seterr(sc, "IPv4 address too long '%.*s'",
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p - ipv4[0], ipv4[0]);
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return (NULL);
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}
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if (*strp == p)
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return *strp;
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if (p == ipv4[0])
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return (ipv4[1] = ipv4[0]);
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char str[INET_ADDRSTRLEN + 1];
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strncpy(str, *strp, p - *strp);
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str[p - *strp] = '\0';
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strncpy(str, ipv4[0], p - ipv4[0]);
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str[p - ipv4[0]] = '\0';
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struct in_addr addr;
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if (inet_aton(str, &addr) != 1) {
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@ -2059,8 +2051,7 @@ get_ipv4(struct snmp_client *sc, const char **strp)
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return (NULL);
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}
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*strp = p;
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return (p);
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return (ipv4[1] = p);
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}
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/**
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@ -2068,24 +2059,19 @@ get_ipv4(struct snmp_client *sc, const char **strp)
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* the last colon (if any). There is no length restriction.
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*
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* \param sc client struct to set errors
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* \param strp possible start of hostname; updated to point to the next
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* character to parse (the trailing NUL character or the last
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* colon)
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* \param host possible start of hostname; start & end updated
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*
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* \return end of address (equals *strp if there is none)
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* \return next character to parse (semicolon or NUL)
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*/
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static inline const char *
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get_host(struct snmp_client *sc __unused, const char **strp)
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get_host(struct snmp_client *sc __unused, const char *host[2])
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{
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const char *p = strrchr(*strp, ':');
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const char *p = strrchr(host[0], ':');
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if (p == NULL) {
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*strp += strlen(*strp);
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return (*strp);
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}
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if (p == NULL)
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return (host[1] = host[0] + strlen(host[0]));
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*strp = p;
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return (p);
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return (host[1] = p);
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}
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/**
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@ -2093,25 +2079,24 @@ get_host(struct snmp_client *sc __unused, const char **strp)
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* of string. The port number must not be empty.
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*
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* \param sc client struct to set errors
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* \param strp possible start of port specification; if this points to a
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* \param port possible start of port specification; if this points to a
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* colon there is a port specification
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*
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* \return end of port number (equals *strp if there is none); NULL
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* if there is no port number
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*/
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static inline const char *
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get_port(struct snmp_client *sc, const char **strp)
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get_port(struct snmp_client *sc, const char *port[2])
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{
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if (**strp != ':')
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return (*strp + 1);
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if (*port[0] != ':')
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return (port[1] = port[0]);
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if ((*strp)[1] == '\0') {
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if (port[0][1] == '\0') {
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seterr(sc, "empty port name");
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return (NULL);
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}
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*strp += strlen(*strp);
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return (*strp);
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return (port[1] = ++(port[0]) + strlen(port[0]));
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}
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/**
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@ -2172,6 +2157,7 @@ int
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snmp_parse_server(struct snmp_client *sc, const char *str)
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{
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const char *const orig = str;
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const char *comm[2], *ipv6[2], *ipv4[2], *host[2], *port[2];
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/* parse input */
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int def_trans = 0, trans = get_transp(sc, &str);
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@ -2181,42 +2167,32 @@ snmp_parse_server(struct snmp_client *sc, const char *str)
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if (orig == str)
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def_trans = 1;
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const char *const comm[2] = {
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str,
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get_comm(sc, &str),
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};
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if (comm[1] == NULL)
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comm[0] = str;
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if ((str = get_comm(sc, comm)) == NULL)
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return (-1);
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const char *const ipv6[2] = {
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str + 1,
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get_ipv6(sc, &str),
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};
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if (ipv6[1] == NULL)
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ipv6[0] = str;
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if ((str = get_ipv6(sc, ipv6)) == NULL)
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return (-1);
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const char *ipv4[2] = {
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str,
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str,
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};
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const char *host[2] = {
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str,
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str,
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};
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if (ipv6[0] == ipv6[1]) {
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ipv4[1] = get_ipv4(sc, &str);
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ipv4[0] = str;
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if ((str = get_ipv4(sc, ipv4)) == NULL) {
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/* This failure isn't fatal: restore str. */
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str = ipv4[0];
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ipv4[0] = ipv4[1] = NULL;
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}
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if (ipv4[0] == ipv4[1])
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host[1] = get_host(sc, &str);
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}
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if (ipv4[0] == ipv4[1]) {
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host[0] = str;
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str = get_host(sc, host);
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} else
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host[0] = host[1] = NULL;
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} else
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ipv4[0] = ipv4[1] = host[0] = host[1] = NULL;
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const char *port[2] = {
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str + 1,
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get_port(sc, &str),
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};
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if (port[1] == NULL)
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port[0] = str;
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if ((str = get_port(sc, port)) == NULL)
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return (-1);
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if (*str != '\0') {
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@ -2247,7 +2223,7 @@ snmp_parse_server(struct snmp_client *sc, const char *str)
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return (-1);
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if (def_trans)
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trans = SNMP_TRANS_UDP;
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} else {
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} else if (host[0] != host[1]) {
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if ((chost = save_str(sc, host)) == NULL)
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return (-1);
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@ -2262,6 +2238,17 @@ snmp_parse_server(struct snmp_client *sc, const char *str)
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break;
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}
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}
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} else switch (trans) {
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case SNMP_TRANS_UDP:
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case SNMP_TRANS_UDP6:
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if ((chost = strdup(DEFAULT_HOST)) == NULL)
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return (-1);
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break;
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case SNMP_TRANS_LOC_DGRAM:
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case SNMP_TRANS_LOC_STREAM:
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if ((chost = strdup(SNMP_DEFAULT_LOCAL)) == NULL)
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return (-1);
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break;
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}
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char *cport;
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