libdw: Fix memory corruption in libdw_find_split_unit.

Found by valgrind when trying to match a split unit from a .dwo file
that doesn't contain the split unit (as first) match. We would close
the split Dwarf too early, before we had inspected all units in it.

Add a testcase that simulates this. Which failed (at least under valgrind
as run by make distcheck) before the fix.

Signed-off-by: Mark Wielaard <mark@klomp.org>

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 22712f1..d187930 100644 (file)
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,8 @@
+2018-05-28  Mark Wielaard  <mark@klomp.org>
+
+       * libdw_find_split_unit.c (__libdw_find_split_unit): End split_dwarf
+       only after we tried every unit id in it.
+
 2018-04-07  Mark Wielaard  <mark@klomp.org>
 
        * libdwP.h (struct Dwarf_CU): Add locs_base.

diff --git a/libdw/libdw_find_split_unit.c b/libdw/libdw_find_split_unit.c
index fcfc46e..d6527e0 100644 (file)
--- a/libdw/libdw_find_split_unit.c
+++ b/libdw/libdw_find_split_unit.c
@@ -94,14 +94,13 @@ __libdw_find_split_unit (Dwarf_CU *cu)
                              elf_cntl (split_dwarf->elf, ELF_C_FDDONE);
                              break;
                            }
-
-                         if (cu->split == (Dwarf_CU *) -1)
-                           dwarf_end (split_dwarf);
                        }
-                     /* Always close, because we don't want to run
-                        out of file descriptors.  See also the
-                        elf_fcntl ELF_C_FDDONE call above.  */
+                     if (cu->split == (Dwarf_CU *) -1)
+                       dwarf_end (split_dwarf);
                    }
+                 /* Always close, because we don't want to run
+                    out of file descriptors.  See also the
+                    elf_fcntl ELF_C_FDDONE call above.  */
                  close (split_fd);
                }
              free (dwo_path);

diff --git a/src/ChangeLog b/src/ChangeLog
index 545fb50..b6f66bd 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2018-05-28  Mark Wielaard  <mark@klomp.org>
+
+       * readelf.c (print_debug_units): Turn "Could not find split compile
+       unit" into an Warning instead of an error.
+
 2018-04-29  Mark Wielaard  <mark@klomp.org>
 
        * readelf.c (parse_opt): Request implicit section_info for "str".

diff --git a/src/readelf.c b/src/readelf.c
index be9fe88..bfa1d16 100644 (file)
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -7668,7 +7668,7 @@ print_debug_units (Dwfl_Module *dwflmod,
          || dwarf_tag (&subdie) == DW_TAG_invalid)
        {
          if (!silent)
-           error (0, 0, gettext ("Could not find split compile unit"));
+           fprintf (stderr, gettext ("Could not find split compile unit"));
        }
       else
        {

diff --git a/tests/ChangeLog b/tests/ChangeLog
index 7ac6bd3..4d69515 100644 (file)
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,9 @@
+2018-05-28  Mark Wielaard  <mark@klomp.org>
+
+       * run-readelf-info-plus.sh: New test.
+       * Makefile.am (TESTS): Add run-readelf-info-plus.sh.
+       (EXTRA_DIST): Likewise.
+
 2018-04-29  Mark Wielaard  <mark@klomp.org>
 
        * run-readelf-addr.sh: New test.

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 4cd0665..e935410 100644 (file)
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -93,7 +93,7 @@ TESTS = run-arextract.sh run-arsymtest.sh run-ar.sh newfile test-nlist \
        run-ranlib-test2.sh run-ranlib-test3.sh run-ranlib-test4.sh \
        run-addrscopes.sh run-strings-test.sh run-funcscopes.sh \
        run-find-prologues.sh run-allregs.sh run-addrcfi.sh \
-       run-nm-self.sh run-readelf-self.sh \
+       run-nm-self.sh run-readelf-self.sh run-readelf-info-plus.sh \
        run-varlocs-self.sh run-exprlocs-self.sh \
        run-readelf-test1.sh run-readelf-test2.sh run-readelf-test3.sh \
        run-readelf-test4.sh run-readelf-twofiles.sh \
@@ -197,7 +197,8 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh run-ar.sh \
             run-elflint-self.sh run-ranlib-test.sh run-ranlib-test2.sh \
             run-ranlib-test3.sh run-ranlib-test4.sh \
             run-addrscopes.sh run-strings-test.sh run-funcscopes.sh \
-            run-nm-self.sh run-readelf-self.sh run-addrcfi.sh \
+            run-nm-self.sh run-readelf-self.sh run-readelf-info-plus.sh \
+            run-addrcfi.sh \
             run-varlocs-self.sh run-exprlocs-self.sh \
             run-find-prologues.sh run-allregs.sh run-native-test.sh \
             run-addrname-test.sh run-dwfl-bug-offline-rel.sh \

diff --git a/tests/run-readelf-info-plus.sh b/tests/run-readelf-info-plus.sh
new file mode 100755 (executable)
index 0000000..ee1db02
--- /dev/null
+++ b/tests/run-readelf-info-plus.sh
@@ -0,0 +1,31 @@
+#! /bin/sh
+# Test for --debug-dump=info+ and finding split unit (in wrong file).
+# Copyright (C) 2018 Red Hat, Inc.
+# This file is part of elfutils.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# elfutils is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. $srcdir/test-subr.sh
+
+# see tests/testfile-dwarf-45.source
+testfiles testfile-splitdwarf-5
+testfiles testfile-world5.dwo
+
+# note, wrong file, renamed as if this contains the correct dwo...
+tempfiles testfile-hello5.dwo
+cp testfile-world5.dwo testfile-hello5.dwo
+
+testrun ${abs_top_builddir}/src/readelf --debug-dump=info+ testfile-splitdwarf-5
+
+exit 0