From dc477e7385e8ab29efb8fadb72ec994077a105c6 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 25 Nov 2015 21:07:17 +0100 Subject: dns-domain: simplify dns_name_is_root() and dns_name_is_single_label() Let's change the return value to bool. If we encounter an error while parsing, return "false" instead of the actual parsing error, after all the specified hostname does not qualify for what the function is supposed to test. Dealing with the additional error codes was always cumbersome, and easily misused, like for example in the DHCP code. Let's also rename the functions from dns_name_root() to dns_name_is_root(), to indicate that this function checks something and returns a bool. Similar for dns_name_is_signal_label(). --- src/libsystemd-network/sd-dhcp-client.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'src/libsystemd-network') diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 5ec0e661f7..f689c59a1a 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -604,7 +604,7 @@ static int client_send_discover(sd_dhcp_client *client) { their messages MUST NOT also send the Host Name option". Just send one of the two depending on the hostname type. */ - if (dns_name_single_label(client->hostname)) { + if (dns_name_is_single_label(client->hostname)) { /* it is unclear from RFC 2131 if client should send hostname in DHCPDISCOVER but dhclient does and so we do as well */ @@ -719,7 +719,7 @@ static int client_send_request(sd_dhcp_client *client) { } if (client->hostname) { - if (dns_name_single_label(client->hostname)) + if (dns_name_is_single_label(client->hostname)) r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, DHCP_OPTION_HOST_NAME, strlen(client->hostname), client->hostname); -- cgit v1.2.3-54-g00ecf From 422baca0f230913158078fddf884e06c8c64a316 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 25 Nov 2015 21:56:48 +0100 Subject: dns-domain: rework dns_label_escape() to not imply memory allocation The new dns_label_escape() call now operates on a buffer passed in, similar to dns_label_unescape(). This should make decoding a bit faster, and nicer. --- src/libsystemd-network/dhcp6-option.c | 18 ++++--- src/resolve/resolved-dns-packet.c | 18 ++++--- src/resolve/resolved-manager.c | 2 +- src/shared/dns-domain.c | 88 +++++++++++++++++++++++++---------- src/shared/dns-domain.h | 5 +- src/test/test-dns-domain.c | 2 +- 6 files changed, 84 insertions(+), 49 deletions(-) (limited to 'src/libsystemd-network') 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; + r = dns_label_escape(label, r, ret + n + !first, DNS_LABEL_ESCAPED_MAX); + if (r < 0) + return r; + if (!first) - ret[n++] = '.'; - else - first = false; + ret[n] = '.'; + } else { + char escaped[DNS_LABEL_ESCAPED_MAX]; - memcpy(ret + n, t, r); + 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) -- cgit v1.2.3-54-g00ecf