Commit 74a16db9 authored by Yang Tse's avatar Yang Tse
Browse files

Initial attempt to detect at configuration time if the getaddrinfo() 

function returns an addrinfo with an unfreeable ai_canonname member ptr.
parent a10044e1

ares/configure.ac

+1 −0
Original line number Diff line number Diff line
@@ -555,6 +555,7 @@ CURL_CHECK_MSG_NOSIGNAL 


CARES_CHECK_FUNC_GETADDRINFO

CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_ADDR

CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME

CARES_CHECK_FUNC_GETHOSTNAME

CARES_CHECK_FUNC_GETSERVBYPORT_R

CARES_CHECK_FUNC_INET_NTOP

ares/m4/cares-functions.m4

+75 −0
Original line number Diff line number Diff line
@@ -440,6 +440,81 @@ AC_DEFUN([CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_ADDR], [ 
])





dnl CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME

dnl -------------------------------------------------

dnl verify if the ai_canonname pointer member of the addrinfo

dnl struct returned by function getaddrinfo is a pointer

dnl which can actually be free()ed or not.



AC_DEFUN([CARES_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME], [

  AC_REQUIRE([CARES_CHECK_FUNC_GETADDRINFO])dnl

  AC_REQUIRE([CARES_INCLUDES_STRING])dnl

  #

  if test "$ac_cv_func_getaddrinfo" = "yes"; then

    AC_MSG_CHECKING([if getaddrinfo returns unfreeable ai_canonname])

    dnl only do runtime verification when not cross-compiling

    if test "x$cross_compiling" != "xyes"; then

      AC_RUN_IFELSE([

        AC_LANG_PROGRAM([[

          $cares_includes_ws2tcpip

          $cares_includes_stdlib

          $cares_includes_sys_socket

          $cares_includes_netdb

          $cares_includes_string

        ]],[[

          char tmp_canonname[80];

          char *ai_canonname, *freed_ptr;

          struct addrinfo hints;

          struct addrinfo *ai = 0;

          int error;



          memset(&hints, 0, sizeof(hints));

          hints.ai_flags = AI_NUMERICHOST|AI_CANONNAME;

          hints.ai_family = AF_UNSPEC;

          hints.ai_socktype = SOCK_STREAM;

          error = getaddrinfo("127.0.0.1", 0, &hints, &ai);

          if(error || !ai)

            /* should not happen, same test already succeeded,   */

            /* assume that returned ai_canonname not unfreeable. */

            exit(0);



          memset(&tmp_canonname, 1, sizeof(tmp_canonname));

          /* attempt to free ai_canonname pointer */

          freed_ptr = ai_canonname = ai->ai_canonname;

          /* seg-fault free'ing an unfreeable ptr would be    */

          /* nice, if this happen exit code will be non-zero. */

          free(ai_canonname);

          /* attempt to write free'ed memory */

          freed_ptr[0] = 'x';

          /* attempt to reuse and clear free'ed memory */

          ai_canonname = calloc(1, sizeof(tmp_canonname));

          /* attempt to read free'ed memory */

          tmp_canonname[0] = freed_ptr[0];

          /* verify if everithing has worked */

          if(tmp_canonname[0] == 'x')

            /* ai_canonname might be unfreeable, ouch! */

            exit(1);

          else

            /* ai_canonname is certainly freeable */

            exit(0);

        ]])

      ],[

        dnl exit code was zero, getaddrinfo behaves nicely.

        AC_MSG_RESULT([no])

      ],[

        dnl exit code wasn't zero, getaddrinfo returns unfreeable ptr.

        AC_MSG_RESULT([yes])

        AC_DEFINE_UNQUOTED(HAVE_GETADDRINFO_UNFREEABLE_AI_CANONNAME, 1,

          [Define to 1 if getaddrinfo returns unfreeable ai_addr pointer.])

      ])

    else

      dnl for cross-compiling a static check would be nice.

      AC_MSG_RESULT([unknown])

    fi

  fi

])





dnl CARES_CHECK_FUNC_GETHOSTNAME

dnl -------------------------------------------------

dnl Verify if gethostname is available, prototyped, and

configure.ac

+1 −0
Original line number Diff line number Diff line
@@ -2018,6 +2018,7 @@ CURL_CHECK_FUNC_FDOPEN 
CURL_CHECK_FUNC_FTRUNCATE

CURL_CHECK_FUNC_GETADDRINFO

CURL_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_ADDR

CURL_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME

CURL_CHECK_FUNC_GETHOSTBYADDR_R

CURL_CHECK_FUNC_GETHOSTBYNAME_R

CURL_CHECK_FUNC_GETHOSTNAME

m4/curl-functions.m4

+75 −0
Original line number Diff line number Diff line
@@ -793,6 +793,81 @@ AC_DEFUN([CURL_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_ADDR], [ 
])





dnl CURL_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME

dnl -------------------------------------------------

dnl verify if the ai_canonname pointer member of the addrinfo

dnl struct returned by function getaddrinfo is a pointer

dnl which can actually be free()ed or not.



AC_DEFUN([CURL_CHECK_FUNC_GETADDRINFO_UNFREEABLE_AI_CANONNAME], [

  AC_REQUIRE([CURL_CHECK_FUNC_GETADDRINFO])dnl

  AC_REQUIRE([CURL_INCLUDES_STRING])dnl

  #

  if test "$ac_cv_func_getaddrinfo" = "yes"; then

    AC_MSG_CHECKING([if getaddrinfo returns unfreeable ai_canonname])

    dnl only do runtime verification when not cross-compiling

    if test "x$cross_compiling" != "xyes"; then

      AC_RUN_IFELSE([

        AC_LANG_PROGRAM([[

          $curl_includes_ws2tcpip

          $curl_includes_stdlib

          $curl_includes_sys_socket

          $curl_includes_netdb

          $curl_includes_string

        ]],[[

          char tmp_canonname[80];

          char *ai_canonname, *freed_ptr;

          struct addrinfo hints;

          struct addrinfo *ai = 0;

          int error;



          memset(&hints, 0, sizeof(hints));

          hints.ai_flags = AI_NUMERICHOST|AI_CANONNAME;

          hints.ai_family = AF_UNSPEC;

          hints.ai_socktype = SOCK_STREAM;

          error = getaddrinfo("127.0.0.1", 0, &hints, &ai);

          if(error || !ai)

            /* should not happen, same test already succeeded,   */

            /* assume that returned ai_canonname not unfreeable. */

            exit(0);



          memset(&tmp_canonname, 1, sizeof(tmp_canonname));

          /* attempt to free ai_canonname pointer */

          freed_ptr = ai_canonname = ai->ai_canonname;

          /* seg-fault free'ing an unfreeable ptr would be    */

          /* nice, if this happen exit code will be non-zero. */

          free(ai_canonname);

          /* attempt to write free'ed memory */

          freed_ptr[0] = 'x';

          /* attempt to reuse and clear free'ed memory */

          ai_canonname = calloc(1, sizeof(tmp_canonname));

          /* attempt to read free'ed memory */

          tmp_canonname[0] = freed_ptr[0];

          /* verify if everithing has worked */

          if(tmp_canonname[0] == 'x')

            /* ai_canonname might be unfreeable, ouch! */

            exit(1);

          else

            /* ai_canonname is certainly freeable */

            exit(0);

        ]])

      ],[

        dnl exit code was zero, getaddrinfo behaves nicely.

        AC_MSG_RESULT([no])

      ],[

        dnl exit code wasn't zero, getaddrinfo returns unfreeable ptr.

        AC_MSG_RESULT([yes])

        AC_DEFINE_UNQUOTED(HAVE_GETADDRINFO_UNFREEABLE_AI_CANONNAME, 1,

          [Define to 1 if getaddrinfo returns unfreeable ai_addr pointer.])

      ])

    else

      dnl for cross-compiling a static check would be nice.

      AC_MSG_RESULT([unknown])

    fi

  fi

])





dnl CURL_CHECK_FUNC_GETHOSTBYADDR_R

dnl -------------------------------------------------

dnl Verify if gethostbyaddr_r is available, prototyped,