resolv: Remove RES_USEBSTRING and its implementation [BZ #20629]

In ns_name_ntop, the NS_CMPRSFLGS check is no longer needed because
labellen (called earlier) already rejects everything which is not
a plain label (compression references and extended label types).

diff --git a/ChangeLog b/ChangeLog
index 361277e..7a124e1 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,18 @@
 2016-10-07  Florian Weimer  <fweimer@redhat.com>
 
+       [BZ #20629]
+       resolv: Remove RES_USEBSTRING and its implementation.
+       * resolv/resolv.h (RES_USEBSTRING): Remove.
+       * resolv/ns_name.c (NS_TYPE_ELT, DNS_LABELTYPE_BITSTRING)
+       (digitvalue, encode_bitstring, decode_bitstring): Remove.
+       (ns_name_ntop, ns_name_pton, ns_name_unpack, ns_name_skip)
+       (labellen): Remove extended label types support.
+       * resolv/res_debug.c (p_option): Remove RES_USEBSTRING handling.
+       * resolv/res_init.c (res_setoptions): Likewise.
+       * resolv/nss_dns/dns-host.c (_nss_dns_gethostbyaddr2_r): Likewise.
+
+2016-10-07  Florian Weimer  <fweimer@redhat.com>
+
        resolv: Remove RES_NOIP6DOTINT and its implementation.
        * resolv/resolv.h (RES_DEFAULT): Remove RES_NOIP6DOTINT.
        (RES_NOIP6DOTINT): Remove.

diff --git a/NEWS b/NEWS
index 49b9180..3b46fb1 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -64,6 +64,11 @@ Version 2.25
   “no-ip6-dotint” had already been the default, and support for the
   “ip6-dotint” option was removed from the Internet in 2006.
 
+* The "ip6-bytestring" resolver option and the corresponding RES_NOIP6DOTINT
+  flag from <resolv.h> have been removed.  The option relied on a
+  backwards-incompatible DNS extension which was never deployed on the
+  Internet.
+
 * The flags RES_AAONLY, RES_PRIMARY, RES_NOCHECKNAME, RES_KEEPTSIG defined
   in the <resolv.h> header file have been deprecated.  They were already
   unimplemented.

diff --git a/resolv/ns_name.c b/resolv/ns_name.c
index 65e7fc8..0d76fe5 100644 (file)
--- a/resolv/ns_name.c
+++ b/resolv/ns_name.c
@@ -29,32 +29,10 @@
 
 # define SPRINTF(x) ((size_t)sprintf x)
 
-#define NS_TYPE_ELT                    0x40 /*%< EDNS0 extended label type */
-#define DNS_LABELTYPE_BITSTRING                0x41
-
 /* Data. */
 
 static const char      digits[] = "0123456789";
 
-static const char digitvalue[256] = {
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
-         0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1, /*64*/
-       -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
-       -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
-};
-
 /* Forward. */
 
 static int             special(int);
@@ -62,12 +40,7 @@ static int           printable(int);
 static int             dn_find(const u_char *, const u_char *,
                                const u_char * const *,
                                const u_char * const *);
-static int             encode_bitstring(const char **, const char *,
-                                        unsigned char **, unsigned char **,
-                                        unsigned const char *);
 static int             labellen(const u_char *);
-static int             decode_bitstring(const unsigned char **,
-                                        char *, const char *);
 
 /* Public. */
 
@@ -115,22 +88,6 @@ ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
                        __set_errno (EMSGSIZE);
                        return (-1);
                }
-               if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
-                       int m;
-
-                       if (n != DNS_LABELTYPE_BITSTRING) {
-                               /* XXX: labellen should reject this case */
-                               __set_errno (EINVAL);
-                               return(-1);
-                       }
-                       if ((m = decode_bitstring(&cp, dn, eom)) < 0)
-                       {
-                               __set_errno (EMSGSIZE);
-                               return(-1);
-                       }
-                       dn += m;
-                       continue;
-               }
                for ((void)NULL; l > 0; l--) {
                        c = *cp++;
                        if (special(c)) {
@@ -192,7 +149,7 @@ int
 ns_name_pton(const char *src, u_char *dst, size_t dstsiz)
 {
        u_char *label, *bp, *eom;
-       int c, n, escaped, e = 0;
+       int c, n, escaped;
        char *cp;
 
        escaped = 0;
@@ -202,28 +159,7 @@ ns_name_pton(const char *src, u_char *dst, size_t dstsiz)
 
        while ((c = *src++) != 0) {
                if (escaped) {
-                       if (c == '[') { /*%< start a bit string label */
-                               if ((cp = strchr(src, ']')) == NULL) {
-                                       __set_errno (EINVAL);
-                                       return(-1);
-                               }
-                               if ((e = encode_bitstring(&src, cp + 2,
-                                                         &label, &bp, eom))
-                                   != 0) {
-                                       __set_errno (e);
-                                       return(-1);
-                               }
-                               escaped = 0;
-                               label = bp++;
-                               if ((c = *src++) == 0)
-                                       goto done;
-                               else if (c != '.') {
-                                       __set_errno (EINVAL);
-                                       return(-1);
-                               }
-                               continue;
-                       }
-                       else if ((cp = strchr(digits, c)) != NULL) {
+                       if ((cp = strchr(digits, c)) != NULL) {
                                n = (cp - digits) * 100;
                                if ((c = *src++) == 0 ||
                                    (cp = strchr(digits, c)) == NULL) {
@@ -291,7 +227,6 @@ ns_name_pton(const char *src, u_char *dst, size_t dstsiz)
                __set_errno (EMSGSIZE);
                return (-1);
        }
-  done:
        if (label >= eom) {
                __set_errno (EMSGSIZE);
                return (-1);
@@ -394,7 +329,6 @@ ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
                /* Check for indirection. */
                switch (n & NS_CMPRSFLGS) {
                case 0:
-               case NS_TYPE_ELT:
                        /* Limit checks. */
                        if ((l = labellen(srcp - 1)) < 0) {
                                __set_errno (EMSGSIZE);
@@ -639,7 +573,6 @@ ns_name_skip(const u_char **ptrptr, const u_char *eom)
 {
        const u_char *cp;
        u_int n;
-       int l;
 
        cp = *ptrptr;
        while (cp < eom && (n = *cp++) != 0) {
@@ -648,13 +581,6 @@ ns_name_skip(const u_char **ptrptr, const u_char *eom)
                case 0:                 /*%< normal case, n == len */
                        cp += n;
                        continue;
-               case NS_TYPE_ELT: /*%< EDNS0 extended label */
-                       if ((l = labellen(cp - 1)) < 0) {
-                               __set_errno (EMSGSIZE);
-                               return(-1);
-                       }
-                       cp += l;
-                       continue;
                case NS_CMPRSFLGS:      /*%< indirection */
                        cp++;
                        break;
@@ -791,180 +717,14 @@ dn_find(const u_char *domain, const u_char *msg,
        return (-1);
 }
 
+/* Return the length of the encoded label starting at LP, or -1 for
+   compression references and extended label types.  */
 static int
-decode_bitstring(const unsigned char **cpp, char *dn, const char *eom)
+labellen (const unsigned char *lp)
 {
-       const unsigned char *cp = *cpp;
-       char *beg = dn, tc;
-       int b, blen, plen, i;
-
-       if ((blen = (*cp & 0xff)) == 0)
-               blen = 256;
-       plen = (blen + 3) / 4;
-       plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
-       if (dn + plen >= eom)
-               return(-1);
-
-       cp++;
-       i = SPRINTF((dn, "\\[x"));
-       if (i < 0)
-               return (-1);
-       dn += i;
-       for (b = blen; b > 7; b -= 8, cp++) {
-               i = SPRINTF((dn, "%02x", *cp & 0xff));
-               if (i < 0)
-                       return (-1);
-               dn += i;
-       }
-       if (b > 4) {
-               tc = *cp++;
-               i = SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
-               if (i < 0)
-                       return (-1);
-               dn += i;
-       } else if (b > 0) {
-               tc = *cp++;
-               i = SPRINTF((dn, "%1x",
-                              ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
-               if (i < 0)
-                       return (-1);
-               dn += i;
-       }
-       i = SPRINTF((dn, "/%d]", blen));
-       if (i < 0)
-               return (-1);
-       dn += i;
-
-       *cpp = cp;
-       return(dn - beg);
-}
-
-static int
-encode_bitstring(const char **bp, const char *end, unsigned char **labelp,
-                unsigned char ** dst, unsigned const char *eom)
-{
-       int afterslash = 0;
-       const char *cp = *bp;
-       unsigned char *tp;
-       char c;
-       const char *beg_blen;
-       char *end_blen = NULL;
-       int value = 0, count = 0, tbcount = 0, blen = 0;
-
-       beg_blen = end_blen = NULL;
-
-       /* a bitstring must contain at least 2 characters */
-       if (end - cp < 2)
-               return(EINVAL);
-
-       /* XXX: currently, only hex strings are supported */
-       if (*cp++ != 'x')
-               return(EINVAL);
-       if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */
-               return(EINVAL);
-
-       for (tp = *dst + 1; cp < end && tp < eom; cp++) {
-               switch((c = *cp)) {
-               case ']':       /*%< end of the bitstring */
-                       if (afterslash) {
-                               if (beg_blen == NULL)
-                                       return(EINVAL);
-                               blen = (int)strtol(beg_blen, &end_blen, 10);
-                               if (*end_blen != ']')
-                                       return(EINVAL);
-                       }
-                       if (count)
-                               *tp++ = ((value << 4) & 0xff);
-                       cp++;   /*%< skip ']' */
-                       goto done;
-               case '/':
-                       afterslash = 1;
-                       break;
-               default:
-                       if (afterslash) {
-                               if (!isdigit(c&0xff))
-                                       return(EINVAL);
-                               if (beg_blen == NULL) {
-
-                                       if (c == '0') {
-                                               /* blen never begings with 0 */
-                                               return(EINVAL);
-                                       }
-                                       beg_blen = cp;
-                               }
-                       } else {
-                               if (!isxdigit(c&0xff))
-                                       return(EINVAL);
-                               value <<= 4;
-                               value += digitvalue[(int)c];
-                               count += 4;
-                               tbcount += 4;
-                               if (tbcount > 256)
-                                       return(EINVAL);
-                               if (count == 8) {
-                                       *tp++ = value;
-                                       count = 0;
-                               }
-                       }
-                       break;
-               }
-       }
-  done:
-       if (cp >= end || tp >= eom)
-               return(EMSGSIZE);
-
-       /*
-        * bit length validation:
-        * If a <length> is present, the number of digits in the <bit-data>
-        * MUST be just sufficient to contain the number of bits specified
-        * by the <length>. If there are insignificant bits in a final
-        * hexadecimal or octal digit, they MUST be zero.
-        * RFC2673, Section 3.2.
-        */
-       if (blen > 0) {
-               int traillen;
-
-               if (((blen + 3) & ~3) != tbcount)
-                       return(EINVAL);
-               traillen = tbcount - blen; /*%< between 0 and 3 */
-               if (((value << (8 - traillen)) & 0xff) != 0)
-                       return(EINVAL);
-       }
-       else
-               blen = tbcount;
-       if (blen == 256)
-               blen = 0;
-
-       /* encode the type and the significant bit fields */
-       **labelp = DNS_LABELTYPE_BITSTRING;
-       **dst = blen;
-
-       *bp = cp;
-       *dst = tp;
-
-       return(0);
-}
-
-static int
-labellen(const u_char *lp)
-{
-       int bitlen;
-       u_char l = *lp;
-
-       if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
-               /* should be avoided by the caller */
-               return(-1);
-       }
-
-       if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
-               if (l == DNS_LABELTYPE_BITSTRING) {
-                       if ((bitlen = *(lp + 1)) == 0)
-                               bitlen = 256;
-                       return((bitlen + 7 ) / 8 + 1);
-               }
-               return(-1);     /*%< unknwon ELT */
-       }
-       return(l);
+  if (*lp <= 63)
+    return *lp;
+  return -1;
 }
 
 /*! \file */

diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index b6245ad..c1333b8 100644 (file)
--- a/resolv/nss_dns/dns-host.c
+++ b/resolv/nss_dns/dns-host.c
@@ -464,19 +464,6 @@ _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af,
               (uaddr[2] & 0xff), (uaddr[1] & 0xff), (uaddr[0] & 0xff));
       break;
     case AF_INET6:
-      /* Only lookup with the byte string format if the user wants it.  */
-      if (__glibc_unlikely (_res.options & RES_USEBSTRING))
-       {
-         qp = stpcpy (qbuf, "\\[x");
-         for (n = 0; n < IN6ADDRSZ; ++n)
-           qp += sprintf (qp, "%02hhx", uaddr[n]);
-         strcpy (qp, "].ip6.arpa");
-         n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR,
-                                host_buffer.buf->buf, 1024, &host_buffer.ptr,
-                                NULL, NULL, NULL, NULL);
-         if (n >= 0)
-           goto got_it_already;
-       }
       qp = qbuf;
       for (n = IN6ADDRSZ - 1; n >= 0; n--)
        {
@@ -504,7 +491,6 @@ _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af,
       return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
     }
 
- got_it_already:
   status = getanswer_r (host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
                        errnop, h_errnop, 0 /* XXX */, ttlp, NULL);
   if (host_buffer.buf != orig_host_buffer)

diff --git a/resolv/res_debug.c b/resolv/res_debug.c
index 0404646..2cbb61c 100644 (file)
--- a/resolv/res_debug.c
+++ b/resolv/res_debug.c
@@ -558,7 +558,6 @@ p_option(u_long option) {
        case RES_USE_INET6:     return "inet6";
        case RES_ROTATE:        return "rotate";
        case RES_BLAST:         return "blast";
-       case RES_USEBSTRING:    return "ip6-bytestring";
        case RES_USE_EDNS0:     return "edns0";
        case RES_SNGLKUP:       return "single-request";
        case RES_SNGLKUPREOP:   return "single-request-reopen";

diff --git a/resolv/res_init.c b/resolv/res_init.c
index 12afb9e..b29c0d4 100644 (file)
--- a/resolv/res_init.c
+++ b/resolv/res_init.c
@@ -438,7 +438,6 @@ res_setoptions(res_state statp, const char *options, const char *source) {
                  } options[] = {
 #define STRnLEN(str) str, sizeof (str) - 1
                    { STRnLEN ("inet6"), 0, RES_USE_INET6 },
-                   { STRnLEN ("ip6-bytestring"), 0, RES_USEBSTRING },
                    { STRnLEN ("rotate"), 0, RES_ROTATE },
                    { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
                    { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },

diff --git a/resolv/resolv.h b/resolv/resolv.h
index 11a7fed..1062903 100644 (file)
--- a/resolv/resolv.h
+++ b/resolv/resolv.h
@@ -197,8 +197,6 @@ struct res_sym {
 #define        RES_KEEPTSIG \
   __glibc_macro_warning ("RES_KEEPTSIG is deprecated") 0x00010000
 #define        RES_BLAST       0x00020000      /* blast all recursive servers */
-#define RES_USEBSTRING 0x00040000      /* IPv6 reverse lookup with byte
-                                          strings */
 #define RES_USE_EDNS0  0x00100000      /* Use EDNS0.  */
 #define RES_SNGLKUP    0x00200000      /* one outstanding request at a time */
 #define RES_SNGLKUPREOP        0x00400000      /* -"-, but open new socket for each