diff --git a/src/libsystemd-network/dhcp6-option.c b/src/libsystemd-network/dhcp6-option.c index 62023a9e49..850212aea1 100644 --- a/src/libsystemd-network/dhcp6-option.c +++ b/src/libsystemd-network/dhcp6-option.c @@ -360,7 +360,6 @@ int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char * /* End of name */ break; else if (c <= 63) { - _cleanup_free_ char *t = NULL; const char *label; /* Literal label */ @@ -369,21 +368,20 @@ int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char * if (pos > optlen) return -EMSGSIZE; - r = dns_label_escape(label, c, &t); - if (r < 0) - goto fail; - - if (!GREEDY_REALLOC0(ret, allocated, n + !first + strlen(t) + 1)) { + if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) { r = -ENOMEM; goto fail; } - if (!first) - ret[n++] = '.'; - else + if (first) first = false; + else + ret[n++] = '.'; + + r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX); + if (r < 0) + goto fail; - memcpy(ret + n, t, r); n += r; continue; } else { diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c index 472486777c..aeff3138d7 100644 --- a/src/resolve/resolved-dns-packet.c +++ b/src/resolve/resolved-dns-packet.c @@ -1145,7 +1145,6 @@ int dns_packet_read_name( /* End of name */ break; else if (c <= 63) { - _cleanup_free_ char *t = NULL; const char *label; /* Literal label */ @@ -1153,21 +1152,20 @@ int dns_packet_read_name( if (r < 0) goto fail; - r = dns_label_escape(label, c, &t); - if (r < 0) - goto fail; - - if (!GREEDY_REALLOC(ret, allocated, n + !first + strlen(t) + 1)) { + if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) { r = -ENOMEM; goto fail; } - if (!first) - ret[n++] = '.'; - else + if (first) first = false; + else + ret[n++] = '.'; + + r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX); + if (r < 0) + goto fail; - memcpy(ret + n, t, r); n += r; continue; } else if (allow_compression && (c & 0xc0) == 0xc0) { diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index 64703ab713..f1f454c786 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -351,7 +351,7 @@ static int determine_hostname(char **llmnr_hostname, char **mdns_hostname) { return -EINVAL; } - r = dns_label_escape(label, r, &n); + r = dns_label_escape_new(label, r, &n); if (r < 0) return log_error_errno(r, "Failed to escape host name: %m"); diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c index 5a9b091ac4..4cf6355b71 100644 --- a/src/shared/dns-domain.c +++ b/src/shared/dns-domain.c @@ -182,30 +182,31 @@ int dns_label_unescape_suffix(const char *name, const char **label_terminal, cha return r; } -int dns_label_escape(const char *p, size_t l, char **ret) { - _cleanup_free_ char *s = NULL; +int dns_label_escape(const char *p, size_t l, char *dest, size_t sz) { char *q; - int r; - - assert(p); - assert(ret); if (l > DNS_LABEL_MAX) return -EINVAL; + if (sz < 1) + return -ENOSPC; - s = malloc(l * 4 + 1); - if (!s) - return -ENOMEM; + assert(p); + assert(dest); - q = s; + q = dest; while (l > 0) { if (*p == '.' || *p == '\\') { + if (sz < 3) + return -ENOSPC; + /* Dot or backslash */ *(q++) = '\\'; *(q++) = *p; + sz -= 2; + } else if (*p == '_' || *p == '-' || (*p >= '0' && *p <= '9') || @@ -213,15 +214,27 @@ int dns_label_escape(const char *p, size_t l, char **ret) { (*p >= 'A' && *p <= 'Z')) { /* Proper character */ + + if (sz < 2) + return -ENOSPC; + *(q++) = *p; + sz -= 1; + } else if ((uint8_t) *p >= (uint8_t) ' ' && *p != 127) { /* Everything else */ + + if (sz < 5) + return -ENOSPC; + *(q++) = '\\'; *(q++) = '0' + (char) ((uint8_t) *p / 100); *(q++) = '0' + (char) (((uint8_t) *p / 10) % 10); *(q++) = '0' + (char) ((uint8_t) *p % 10); + sz -= 4; + } else return -EINVAL; @@ -230,8 +243,28 @@ int dns_label_escape(const char *p, size_t l, char **ret) { } *q = 0; + return (int) (q - dest); +} + +int dns_label_escape_new(const char *p, size_t l, char **ret) { + _cleanup_free_ char *s = NULL; + int r; + + assert(p); + assert(ret); + + if (l > DNS_LABEL_MAX) + return -EINVAL; + + s = new(char, DNS_LABEL_ESCAPED_MAX); + if (!s) + return -ENOMEM; + + r = dns_label_escape(p, l, s, DNS_LABEL_ESCAPED_MAX); + if (r < 0) + return r; + *ret = s; - r = q - s; s = NULL; return r; @@ -351,28 +384,32 @@ int dns_name_concat(const char *a, const char *b, char **_ret) { if (k > 0) r = k; - r = dns_label_escape(label, r, &t); - if (r < 0) - return r; - if (_ret) { - if (!GREEDY_REALLOC(ret, allocated, n + !first + strlen(t) + 1)) + if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) return -ENOMEM; - if (!first) - ret[n++] = '.'; - else - first = false; + r = dns_label_escape(label, r, ret + n + !first, DNS_LABEL_ESCAPED_MAX); + if (r < 0) + return r; - memcpy(ret + n, t, r); + if (!first) + ret[n] = '.'; + } else { + char escaped[DNS_LABEL_ESCAPED_MAX]; + + r = dns_label_escape(label, r, escaped, sizeof(escaped)); + if (r < 0) + return r; } + if (!first) + n++; + else + first = false; + n += r; } - if (n > DNS_NAME_MAX) - return -EINVAL; - if (_ret) { if (!GREEDY_REALLOC(ret, allocated, n + 1)) return -ENOMEM; @@ -892,7 +929,8 @@ bool dns_service_name_is_valid(const char *name) { } int dns_service_join(const char *name, const char *type, const char *domain, char **ret) { - _cleanup_free_ char *escaped = NULL, *n = NULL; + char escaped[DNS_LABEL_ESCAPED_MAX]; + _cleanup_free_ char *n = NULL; int r; assert(type); @@ -908,7 +946,7 @@ int dns_service_join(const char *name, const char *type, const char *domain, cha if (!dns_service_name_is_valid(name)) return -EINVAL; - r = dns_label_escape(name, strlen(name), &escaped); + r = dns_label_escape(name, strlen(name), escaped, sizeof(escaped)); if (r < 0) return r; diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h index 2f557d618e..99c72574db 100644 --- a/src/shared/dns-domain.h +++ b/src/shared/dns-domain.h @@ -26,11 +26,12 @@ #include "in-addr-util.h" #define DNS_LABEL_MAX 63 -#define DNS_NAME_MAX 255 +#define DNS_LABEL_ESCAPED_MAX (DNS_LABEL_MAX*4+1) int dns_label_unescape(const char **name, char *dest, size_t sz); int dns_label_unescape_suffix(const char *name, const char **label_end, char *dest, size_t sz); -int dns_label_escape(const char *p, size_t l, char **ret); +int dns_label_escape(const char *p, size_t l, char *dest, size_t sz); +int dns_label_escape_new(const char *p, size_t l, char **ret); int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max); int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max); diff --git a/src/test/test-dns-domain.c b/src/test/test-dns-domain.c index df34b72ab6..f010e4e19a 100644 --- a/src/test/test-dns-domain.c +++ b/src/test/test-dns-domain.c @@ -126,7 +126,7 @@ static void test_dns_label_escape_one(const char *what, size_t l, const char *ex _cleanup_free_ char *t = NULL; int r; - r = dns_label_escape(what, l, &t); + r = dns_label_escape_new(what, l, &t); assert_se(r == ret); if (r < 0)