configure: add support for cap-ng package

It uses '--with-cap-ng', for using libcap-ng [default=yes, if available]

diff --git a/config.h.in b/config.h.in
index 43a6bc1b753ea43aeeff6c1a81608ab6af9e1f02..11ce977b5347e826e96db9ad4e03fdfb9e1d3d68 100644 (file)
--- a/config.h.in
+++ b/config.h.in
@@ -18,6 +18,9 @@
 /* Define to 1 if you have the `cap_ioctls_limit' function. */
 #undef HAVE_CAP_IOCTLS_LIMIT
 
+/* Define to 1 if you have the <cap-ng.h> header file. */
+#undef HAVE_CAP_NG_H
+
 /* Define to 1 if you have the `cap_rights_limit' function. */
 #undef HAVE_CAP_RIGHTS_LIMIT
 
@@ -52,6 +55,9 @@
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
+/* Define to 1 if you have the `cap-ng' library (-lcap-ng). */
+#undef HAVE_LIBCAP_NG
+
 /* Define to 1 if you have the `crypto' library (-lcrypto). */
 #undef HAVE_LIBCRYPTO
 

diff --git a/configure b/configure
index 87d6992bd08e60d548f17669a43e97fb56feea9b..293edb14c12ef9ee3b9da82ce81f165f57462d49 100755 (executable)
--- a/configure
+++ b/configure
@@ -707,6 +707,7 @@ with_sandbox_capsicum
 enable_ipv6
 with_system_libpcap
 with_crypto
+with_cap_ng
 '
       ac_precious_vars='build_alias
 host_alias
@@ -1346,6 +1347,7 @@ Optional Packages:
                           available]
   --with-system-libpcap   don't use local pcap library
   --with-crypto           use OpenSSL libcrypto [default=yes, if available]
+  --with-cap-ng           use libcap-ng [default=yes, if available]
 
 Some influential environment variables:
   CC          C compiler command
@@ -6736,7 +6738,7 @@ fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
     if test "$ac_lbl_cv_pcap_version_defined" = yes ; then
-       { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+       { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
 
 $as_echo "#define HAVE_PCAP_VERSION 1" >>confdefs.h
@@ -8176,6 +8178,98 @@ done
 
 fi
 
+# Check for libcap-ng
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to use libcap-ng" >&5
+$as_echo_n "checking whether to use libcap-ng... " >&6; }
+# Specify location for both includes and libraries.
+want_libcap_ng=ifavailable
+
+# Check whether --with-cap_ng was given.
+if test "${with_cap_ng+set}" = set; then :
+  withval=$with_cap_ng;
+       if test $withval = no
+       then
+               want_libcap_ng=no
+               { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+       elif test $withval = yes
+       then
+               want_libcap_ng=yes
+               { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+       fi
+
+else
+
+       #
+       # Use libcap-ng if it's present, otherwise don't.
+       #
+       want_libcap_ng=ifavailable
+       { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes, if available" >&5
+$as_echo "yes, if available" >&6; }
+
+fi
+
+if test "$want_libcap_ng" != "no"; then
+       { $as_echo "$as_me:${as_lineno-$LINENO}: checking for capng_change_id in -lcap-ng" >&5
+$as_echo_n "checking for capng_change_id in -lcap-ng... " >&6; }
+if ${ac_cv_lib_cap_ng_capng_change_id+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lcap-ng  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char capng_change_id ();
+int
+main ()
+{
+return capng_change_id ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_cap_ng_capng_change_id=yes
+else
+  ac_cv_lib_cap_ng_capng_change_id=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_cap_ng_capng_change_id" >&5
+$as_echo "$ac_cv_lib_cap_ng_capng_change_id" >&6; }
+if test "x$ac_cv_lib_cap_ng_capng_change_id" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBCAP_NG 1
+_ACEOF
+
+  LIBS="-lcap-ng $LIBS"
+
+fi
+
+       for ac_header in cap-ng.h
+do :
+  ac_fn_c_check_header_mongrel "$LINENO" "cap-ng.h" "ac_cv_header_cap_ng_h" "$ac_includes_default"
+if test "x$ac_cv_header_cap_ng_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_CAP_NG_H 1
+_ACEOF
+
+fi
+
+done
+
+fi
+
 if test "$missing_includes" = "yes"; then
        CPPFLAGS="$CPPFLAGS -I$srcdir/missing"
        V_INCLS="$V_INCLS -I$srcdir/missing"

diff --git a/configure.in b/configure.in
index 7c860dc0787cc38380fd7371706c97b59f5f31ab..1f10dc5e7e9e3c03d6459243d81b2a7e180118bf 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -854,7 +854,7 @@ if test $ac_cv_func_pcap_lib_version = "no" ; then
        ac_lbl_cv_pcap_version_defined=yes,
        ac_lbl_cv_pcap_version_defined=no)
     if test "$ac_lbl_cv_pcap_version_defined" = yes ; then
-       AC_MSG_RESULT(yes)
+       AC_MSG_RESULT(yes)
        AC_DEFINE(HAVE_PCAP_VERSION, 1, [define if libpcap has pcap_version])
     else
        AC_MSG_RESULT(no)
@@ -1110,6 +1110,35 @@ if test "$want_libcrypto" != "no"; then
        AC_CHECK_HEADERS(openssl/evp.h)
 fi
 
+# Check for libcap-ng
+AC_MSG_CHECKING(whether to use libcap-ng)
+# Specify location for both includes and libraries.
+want_libcap_ng=ifavailable
+AC_ARG_WITH(cap_ng,
+    AS_HELP_STRING([--with-cap-ng],
+                  [use libcap-ng @<:@default=yes, if available@:>@]),
+[
+       if test $withval = no
+       then
+               want_libcap_ng=no
+               AC_MSG_RESULT(no)
+       elif test $withval = yes
+       then
+               want_libcap_ng=yes
+               AC_MSG_RESULT(yes)
+       fi
+],[
+       #
+       # Use libcap-ng if it's present, otherwise don't.
+       #
+       want_libcap_ng=ifavailable
+       AC_MSG_RESULT([yes, if available])
+])
+if test "$want_libcap_ng" != "no"; then
+       AC_CHECK_LIB(cap-ng, capng_change_id)
+       AC_CHECK_HEADERS(cap-ng.h)
+fi
+
 dnl
 dnl set additional include path if necessary
 if test "$missing_includes" = "yes"; then

diff --git a/tcpdump.c b/tcpdump.c
index 1eb2e206b6ec1b9a6a12eebc8f576117983aa9b1..bd1664c5301497efbdef3f450f41b2af34cac9a9 100644 (file)
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -101,10 +101,18 @@ extern int SIZE_BUF;
 #include <grp.h>
 #endif /* WIN32 */
 
-/* capabilities convinience library */
+/* capabilities convenience library */
+/* If a code depends on HAVE_LIBCAP_NG, it depends also on HAVE_CAP_NG_H.
+ * If HAVE_CAP_NG_H is not defined, undefine HAVE_LIBCAP_NG.
+ * Thus, the later tests are done only on HAVE_LIBCAP_NG.
+ */
+#ifdef HAVE_LIBCAP_NG
 #ifdef HAVE_CAP_NG_H
 #include <cap-ng.h>
+#else
+#undef HAVE_LIBCAP_NG
 #endif /* HAVE_CAP_NG_H */
+#endif /* HAVE_LIBCAP_NG */
 
 #include "netdissect.h"
 #include "interface.h"
@@ -734,7 +742,7 @@ droproot(const char *username, const char *chroot_dir)
                                exit(1);
                        }
                }
-#ifdef HAVE_CAP_NG_H
+#ifdef HAVE_LIBCAP_NG
                int ret = capng_change_id(pw->pw_uid, pw->pw_gid, CAPNG_NO_FLAG);
                if (ret < 0) {
                        fprintf(stderr, "error : ret %d\n", ret);
@@ -749,6 +757,7 @@ droproot(const char *username, const char *chroot_dir)
                        CAP_SETUID,
                        CAP_SETGID,
                        -1);
+
                capng_apply(CAPNG_SELECT_BOTH);
 
 #else
@@ -764,7 +773,7 @@ droproot(const char *username, const char *chroot_dir)
                else {
                        fprintf(stderr, "dropped privs to %s\n", username);
                }
-#endif /* HAVE_CAP_NG_H */
+#endif /* HAVE_LIBCAP_NG */
        }
        else {
                fprintf(stderr, "tcpdump: Couldn't find user '%.32s'\n",
@@ -1582,7 +1591,7 @@ main(int argc, char **argv)
                        status = pcap_set_tstamp_type(pd, jflag);
                        if (status < 0)
                                error("%s: Can't set time stamp type: %s",
-                                   device, pcap_statustostr(status));
+                                     device, pcap_statustostr(status));
                }
 #endif
                status = pcap_activate(pd);
@@ -1729,7 +1738,7 @@ main(int argc, char **argv)
         */
 
        if (getuid() == 0 || geteuid() == 0) {
-#ifdef HAVE_CAP_NG_H
+#ifdef HAVE_LIBCAP_NG
                /* Drop all capabilities from effective set */
                capng_clear(CAPNG_EFFECTIVE);
                /* We are running as root and we will be writing to savefile */
@@ -1744,7 +1753,7 @@ main(int argc, char **argv)
                                -1);
                        capng_apply(CAPNG_SELECT_BOTH);
                }
-#endif /* HAVE_CAP_NG_H */
+#endif /* HAVE_LIBCAP_NG */
                if (username || chroot_dir)
                        droproot(username, chroot_dir);
 
@@ -1783,10 +1792,10 @@ main(int argc, char **argv)
                  MakeFilename(dumpinfo.CurrentFileName, WFileName, 0, 0);
 
                p = pcap_dump_open(pd, dumpinfo.CurrentFileName);
-#ifdef HAVE_CAP_NG_H
+#ifdef HAVE_LIBCAP_NG
         /* Give up capabilities, clear Effective set */
         capng_clear(CAPNG_EFFECTIVE);
-#endif
+#endif /* HAVE_LIBCAP_NG */
                if (p == NULL)
                        error("%s", pcap_geterr(pd));
 #ifdef HAVE_CAPSICUM
@@ -2200,10 +2209,10 @@ dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *s
                        else
                                MakeFilename(dump_info->CurrentFileName, dump_info->WFileName, 0, 0);
 
-#ifdef HAVE_CAP_NG_H
+#ifdef HAVE_LIBCAP_NG
                        capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
                        capng_apply(CAPNG_EFFECTIVE);
-#endif /* HAVE_CAP_NG_H */
+#endif /* HAVE_LIBCAP_NG */
 #ifdef HAVE_CAPSICUM
                        fd = openat(dump_info->dirfd,
                            dump_info->CurrentFileName,
@@ -2221,10 +2230,10 @@ dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *s
 #else  /* !HAVE_CAPSICUM */
                        dump_info->p = pcap_dump_open(dump_info->pd, dump_info->CurrentFileName);
 #endif
-#ifdef HAVE_CAP_NG_H
+#ifdef HAVE_LIBCAP_NG
                        capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
                        capng_apply(CAPNG_EFFECTIVE);
-#endif /* HAVE_CAP_NG_H */
+#endif /* HAVE_LIBCAP_NG */
                        if (dump_info->p == NULL)
                                error("%s", pcap_geterr(pd));
 #ifdef HAVE_CAPSICUM