X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fnss-resolve%2Fnss-resolve.c;h=b2cb19a7b42918afd2dbb21ed50ecf88352d5156;hp=7b0c24fbeacb1dc073aa95df8ef1ae132ea86ba8;hb=7c2a5e264c1d94ca9ba9c49acfdcd541c8a63a88;hpb=4d1cf1e229c9bdbc44778c0863eaad918f5724e7 diff --git a/src/nss-resolve/nss-resolve.c b/src/nss-resolve/nss-resolve.c index 7b0c24fbe..b2cb19a7b 100644 --- a/src/nss-resolve/nss-resolve.c +++ b/src/nss-resolve/nss-resolve.c @@ -29,6 +29,7 @@ #include #include #include +#include #include "sd-bus.h" #include "bus-util.h" @@ -43,17 +44,41 @@ NSS_GETHOSTBYADDR_PROTOTYPES(resolve); #define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC) -static int count_addresses(sd_bus_message *m, unsigned af, unsigned *ret) { - unsigned c = 0; - int r; +typedef void (*voidfunc_t)(void); + +static voidfunc_t find_fallback(const char *module, const char *symbol) { + void *dl; + + /* Try to find a fallback NSS module symbol */ + + dl = dlopen(module, RTLD_LAZY|RTLD_NODELETE); + if (!dl) + return NULL; + + return dlsym(dl, symbol); +} + +static bool bus_error_shall_fallback(sd_bus_error *e) { + return sd_bus_error_has_name(e, SD_BUS_ERROR_SERVICE_UNKNOWN) || + sd_bus_error_has_name(e, SD_BUS_ERROR_NAME_HAS_NO_OWNER) || + sd_bus_error_has_name(e, SD_BUS_ERROR_NO_REPLY) || + sd_bus_error_has_name(e, SD_BUS_ERROR_ACCESS_DENIED); +} + +static int count_addresses(sd_bus_message *m, int af, const char **canonical) { + int c = 0, r; assert(m); - assert(ret); + assert(canonical); + + r = sd_bus_message_enter_container(m, 'a', "(iayi)"); + if (r < 0) + return r; - while ((r = sd_bus_message_enter_container(m, 'r', "yayi")) > 0) { - unsigned char family; + while ((r = sd_bus_message_enter_container(m, 'r', "iayi")) > 0) { + int family; - r = sd_bus_message_read(m, "y", &family); + r = sd_bus_message_read(m, "i", &family); if (r < 0) return r; @@ -73,12 +98,19 @@ static int count_addresses(sd_bus_message *m, unsigned af, unsigned *ret) { if (r < 0) return r; - r = sd_bus_message_rewind(m, false); + r = sd_bus_message_exit_container(m); if (r < 0) return r; - *ret = c; - return 0; + r = sd_bus_message_read(m, "s", canonical); + if (r < 0) + return r; + + r = sd_bus_message_rewind(m, true); + if (r < 0) + return r; + + return c; } enum nss_status _nss_resolve_gethostbyname4_r( @@ -92,10 +124,10 @@ enum nss_status _nss_resolve_gethostbyname4_r( _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; struct gaih_addrtuple *r_tuple, *r_tuple_first = NULL; _cleanup_bus_unref_ sd_bus *bus = NULL; + const char *canonical = NULL; size_t l, ms, idx; char *r_name; - unsigned i = 0, c = 0; - int r; + int c, r, i = 0; assert(name); assert(pat); @@ -121,7 +153,7 @@ enum nss_status _nss_resolve_gethostbyname4_r( if (r < 0) goto fail; - r = sd_bus_message_append(req, "sy", name, AF_UNSPEC); + r = sd_bus_message_append(req, "si", name, AF_UNSPEC); if (r < 0) goto fail; @@ -133,26 +165,45 @@ enum nss_status _nss_resolve_gethostbyname4_r( return NSS_STATUS_NOTFOUND; } + if (bus_error_shall_fallback(&error)) { + + enum nss_status (*fallback)( + const char *name, + struct gaih_addrtuple **pat, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp); + + fallback = (enum nss_status (*)(const char *name, + struct gaih_addrtuple **pat, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp)) + find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyname4_r"); + if (fallback) + return fallback(name, pat, buffer, buflen, errnop, h_errnop, ttlp); + } + *errnop = -r; *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; } - r = sd_bus_message_enter_container(reply, 'a', "(yayi)"); - if (r < 0) + c = count_addresses(reply, AF_UNSPEC, &canonical); + if (c < 0) { + r = c; goto fail; - - r = count_addresses(reply, AF_UNSPEC, &c); - if (r < 0) - goto fail; - - if (c <= 0) { + } + if (c == 0) { *errnop = ESRCH; *h_errnop = HOST_NOT_FOUND; return NSS_STATUS_NOTFOUND; } - l = strlen(name); + if (isempty(canonical)) + canonical = name; + + l = strlen(canonical); ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * c; if (buflen < ms) { *errnop = ENOMEM; @@ -162,18 +213,22 @@ enum nss_status _nss_resolve_gethostbyname4_r( /* First, append name */ r_name = buffer; - memcpy(r_name, name, l+1); + memcpy(r_name, canonical, l+1); idx = ALIGN(l+1); /* Second, append addresses */ r_tuple_first = (struct gaih_addrtuple*) (buffer + idx); - while ((r = sd_bus_message_enter_container(reply, 'r', "yayi")) > 0) { - unsigned char family; + + r = sd_bus_message_enter_container(reply, 'a', "(iayi)"); + if (r < 0) + goto fail; + + while ((r = sd_bus_message_enter_container(reply, 'r', "iayi")) > 0) { + int family, ifindex; const void *a; - int ifindex; size_t sz; - r = sd_bus_message_read(reply, "y", &family); + r = sd_bus_message_read(reply, "i", &family); if (r < 0) goto fail; @@ -192,7 +247,7 @@ enum nss_status _nss_resolve_gethostbyname4_r( if (!IN_SET(family, AF_INET, AF_INET6)) continue; - if (sz != PROTO_ADDRESS_SIZE(family)) { + if (sz != FAMILY_ADDRESS_SIZE(family)) { r = -EINVAL; goto fail; } @@ -212,13 +267,10 @@ enum nss_status _nss_resolve_gethostbyname4_r( idx += ALIGN(sizeof(struct gaih_addrtuple)); i++; } - - assert(i == c); - - r = sd_bus_message_exit_container(reply); if (r < 0) goto fail; + assert(i == c); assert(idx == ms); if (*pat) @@ -250,9 +302,9 @@ enum nss_status _nss_resolve_gethostbyname3_r( _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; char *r_name, *r_aliases, *r_addr, *r_addr_list; _cleanup_bus_unref_ sd_bus *bus = NULL; - unsigned c = 0, i = 0; size_t l, idx, ms, alen; - int r; + const char *canonical; + int c, r, i = 0; assert(name); assert(result); @@ -286,7 +338,7 @@ enum nss_status _nss_resolve_gethostbyname3_r( if (r < 0) goto fail; - r = sd_bus_message_append(req, "sy", name, af); + r = sd_bus_message_append(req, "si", name, af); if (r < 0) goto fail; @@ -298,27 +350,50 @@ enum nss_status _nss_resolve_gethostbyname3_r( return NSS_STATUS_NOTFOUND; } + if (bus_error_shall_fallback(&error)) { + + enum nss_status (*fallback)( + const char *name, + int af, + struct hostent *result, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp, + char **canonp); + + fallback = (enum nss_status (*)(const char *name, + int af, + struct hostent *result, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp, + char **canonp)) + find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyname3_r"); + if (fallback) + return fallback(name, af, result, buffer, buflen, errnop, h_errnop, ttlp, canonp); + } + *errnop = -r; *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; } - r = sd_bus_message_enter_container(reply, 'a', "(yayi)"); - if (r < 0) - goto fail; - - r = count_addresses(reply, af, &c); - if (r < 0) + c = count_addresses(reply, af, &canonical); + if (c < 0) { + r = c; goto fail; - - if (c <= 0) { + } + if (c == 0) { *errnop = ESRCH; *h_errnop = HOST_NOT_FOUND; return NSS_STATUS_NOTFOUND; } - alen = PROTO_ADDRESS_SIZE(af); - l = strlen(name); + if (isempty(canonical)) + canonical = name; + + alen = FAMILY_ADDRESS_SIZE(af); + l = strlen(canonical); ms = ALIGN(l+1) + sizeof(char*) + @@ -333,23 +408,27 @@ enum nss_status _nss_resolve_gethostbyname3_r( /* First, append name */ r_name = buffer; - memcpy(r_name, name, l+1); + memcpy(r_name, canonical, l+1); idx = ALIGN(l+1); - /* Second, create aliases array */ + /* Second, create empty aliases array */ r_aliases = buffer + idx; ((char**) r_aliases)[0] = NULL; idx += sizeof(char*); /* Third, append addresses */ r_addr = buffer + idx; - while ((r = sd_bus_message_enter_container(reply, 'r', "yayi")) > 0) { - unsigned char family; + + r = sd_bus_message_enter_container(reply, 'a', "(iayi)"); + if (r < 0) + goto fail; + + while ((r = sd_bus_message_enter_container(reply, 'r', "iayi")) > 0) { + int family, ifindex; const void *a; - int ifindex; size_t sz; - r = sd_bus_message_read(reply, "y", &family); + r = sd_bus_message_read(reply, "i", &family); if (r < 0) goto fail; @@ -381,15 +460,13 @@ enum nss_status _nss_resolve_gethostbyname3_r( memcpy(r_addr + i*ALIGN(alen), a, alen); i++; } + if (r < 0) + goto fail; assert(i == c); idx += c * ALIGN(alen); - r = sd_bus_message_exit_container(reply); - if (r < 0) - goto fail; - - /* Third, append address pointer array */ + /* Fourth, append address pointer array */ r_addr_list = buffer + idx; for (i = 0; i < c; i++) ((char**) r_addr_list)[i] = r_addr + i*ALIGN(alen); @@ -448,7 +525,7 @@ enum nss_status _nss_resolve_gethostbyaddr2_r( return NSS_STATUS_UNAVAIL; } - if (len != PROTO_ADDRESS_SIZE(af)) { + if (len != FAMILY_ADDRESS_SIZE(af)) { *errnop = EINVAL; *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; @@ -472,7 +549,7 @@ enum nss_status _nss_resolve_gethostbyaddr2_r( if (r < 0) goto fail; - r = sd_bus_message_append(req, "y", af); + r = sd_bus_message_append(req, "i", af); if (r < 0) goto fail; @@ -492,6 +569,29 @@ enum nss_status _nss_resolve_gethostbyaddr2_r( return NSS_STATUS_NOTFOUND; } + if (bus_error_shall_fallback(&error)) { + + enum nss_status (*fallback)( + const void* addr, socklen_t len, + int af, + struct hostent *result, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp); + + fallback = (enum nss_status (*)( + const void* addr, socklen_t len, + int af, + struct hostent *result, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp)) + find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyaddr2_r"); + + if (fallback) + return fallback(addr, len, af, result, buffer, buflen, errnop, h_errnop, ttlp); + } + *errnop = -r; *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; @@ -560,6 +660,8 @@ enum nss_status _nss_resolve_gethostbyaddr2_r( idx += ALIGN(l+1); } + if (r < 0) + goto fail; ((char**) r_aliases)[c-1] = NULL; assert(idx == ms);