Add support for zlib compressed elf .debug_frame sections

In case zlib support is not available, fail to load instead of
crashing while trying to read invalid data.

4 files changed, 67 insertions, 12 deletions

diff --git a/configure.ac b/configure.ac
index 8e62b8bd..11aeb2d2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -302,6 +302,23 @@ fi
 AC_SUBST([LIBLZMA])
 AM_CONDITIONAL(HAVE_LZMA, test x$enable_minidebuginfo = xyes)
 
+LIBZ=
+AC_MSG_CHECKING([whether to support ZLIB-compressed symbol tables])
+AC_ARG_ENABLE(zlibdebuginfo,
+AS_HELP_STRING([--enable-zlibdebuginfo], [Enables support for ZLIB-compressed symbol tables]),, [enable_zlibdebuginfo=auto])
+AC_MSG_RESULT([$enable_zlibdebuginfo])
+if test x$enable_zlibdebuginfo != xno; then
+   AC_CHECK_LIB([z], [uncompress],
+   [LIBZ=-lz
+    AC_DEFINE([HAVE_ZLIB], [1], [Define if you have libz])
+    enable_zlibdebuginfo=yes],
+   [if test x$enable_zlibdebuginfo = xyes; then
+      AC_MSG_FAILURE([libz not found])
+    fi])
+fi
+AC_SUBST([LIBZ])
+AM_CONDITIONAL(HAVE_ZLIB, test x$enable_zlibdebuginfo = xyes)
+
 AC_MSG_CHECKING([whether to support UNW_CACHE_PER_THREAD])
 AC_ARG_ENABLE([per-thread-cache],
 AS_HELP_STRING([--enable-per-thread-cache], [build with support for UNW_CACHE_PER_THREAD (which imposes a hight TLS memory usage) (default: disabled)]))
diff --git a/src/Makefile.am b/src/Makefile.am
index bc37b123..ff977446 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -68,7 +68,7 @@ libunwind_coredump_la_SOURCES = \
 	coredump/_UPT_resume.c
 libunwind_coredump_la_LDFLAGS = $(COMMON_SO_LDFLAGS) \
 				-version-info $(COREDUMP_SO_VERSION)
-libunwind_coredump_la_LIBADD = $(LIBLZMA)
+libunwind_coredump_la_LIBADD = $(LIBLZMA) $(LIBZ)
 noinst_HEADERS += coredump/_UCD_internal.h coredump/_UCD_lib.h
 
 ### libunwind-setjmp:
@@ -183,9 +183,9 @@ noinst_HEADERS += elf32.h elf64.h elfxx.h
 libunwind_elf32_la_SOURCES = elf32.c
 libunwind_elf64_la_SOURCES = elf64.c
 libunwind_elfxx_la_SOURCES = elfxx.c
-libunwind_elf32_la_LIBADD  = $(LIBLZMA)
-libunwind_elf64_la_LIBADD  = $(LIBLZMA)
-libunwind_elfxx_la_LIBADD  = $(LIBLZMA)
+libunwind_elf32_la_LIBADD  = $(LIBLZMA) $(LIBZ)
+libunwind_elf64_la_LIBADD  = $(LIBLZMA) $(LIBZ)
+libunwind_elfxx_la_LIBADD  = $(LIBLZMA) $(LIBZ)
 
 noinst_LTLIBRARIES += $(LIBUNWIND_ELF)
 libunwind_la_LIBADD += $(LIBUNWIND_ELF)
@@ -732,7 +732,7 @@ endif
 libunwind_la_LDFLAGS =	$(COMMON_SO_LDFLAGS) -XCClinker -nostdlib \
 			$(LDFLAGS_STATIC_LIBCXA) -version-info $(SOVERSION)
 libunwind_la_LIBADD  += -lc $(LIBCRTS)
-libunwind_la_LIBADD += $(LIBLZMA)
+libunwind_la_LIBADD += $(LIBLZMA) $(LIBZ)
 
 AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/include/tdep-$(arch) -I.
 AM_CCASFLAGS = $(AM_CPPFLAGS)
diff --git a/src/dwarf/Gfind_proc_info-lsb.c b/src/dwarf/Gfind_proc_info-lsb.c
index 7d0c70f2..678c80bf 100644
--- a/src/dwarf/Gfind_proc_info-lsb.c
+++ b/src/dwarf/Gfind_proc_info-lsb.c
@@ -34,6 +34,10 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #include "dwarf-eh.h"
 #include "libunwind_i.h"
 
+#ifdef HAVE_ZLIB
+#include <zlib.h>
+#endif /* HAVE_ZLIB */
+
 struct table_entry
   {
     int32_t start_ip_offset;
@@ -123,14 +127,48 @@ load_debug_frame (const char *file, char **buf, size_t *bufsize, int is_local)
       return 1;
     }
 
-  *bufsize = shdr->sh_size;
-  GET_MEMORY(*buf, *bufsize);
-
-  memcpy(*buf, shdr->sh_offset + ei.image, *bufsize);
+  if (shdr->sh_flags & SHF_COMPRESSED)
+    {
+      unsigned long destSize;
+      Elf_W (Chdr) *chdr = (shdr->sh_offset + ei.image);
+#ifdef HAVE_ZLIB
+      if (chdr->ch_type == ELFCOMPRESS_ZLIB)
+	{
+	  *bufsize = destSize = chdr->ch_size;
+	  GET_MEMORY(*buf, *bufsize);
+	  ret = uncompress((unsigned char *)*buf, &destSize,
+			   shdr->sh_offset + ei.image + sizeof(*chdr),
+			   shdr->sh_size - sizeof(*chdr));
+	  if (ret != Z_OK)
+	    {
+	      Debug (2, "failed to decompress zlib .debug_frame, skipping\n");
+	      munmap(*buf, *bufsize);
+	      munmap(ei.image, ei.size);
+	      return 1;
+	    }
+
+	  Debug (4, "read %zd->%zd bytes of .debug_frame from offset %zd\n",
+		 shdr->sh_size, *bufsize, shdr->sh_offset);
+	}
+      else
+#endif /* HAVE_ZLIB */
+	{
+	  Debug (2, "unknown compression type %d, skipping\n",
+		 chdr->ch_type);
+          munmap(ei.image, ei.size);
+	  return 1;
+        }
+    }
+  else
+    {
+      *bufsize = shdr->sh_size;
+      GET_MEMORY(*buf, *bufsize);
 
-  Debug (4, "read %zd bytes of .debug_frame from offset %zd\n",
-	 *bufsize, shdr->sh_offset);
+      memcpy(*buf, shdr->sh_offset + ei.image, *bufsize);
 
+      Debug (4, "read %zd bytes of .debug_frame from offset %zd\n",
+	     *bufsize, shdr->sh_offset);
+    }
   munmap(ei.image, ei.size);
   return 0;
 }
diff --git a/src/unwind/libunwind.pc.in b/src/unwind/libunwind.pc.in
index 1505c5d6..9a65faf3 100644
--- a/src/unwind/libunwind.pc.in
+++ b/src/unwind/libunwind.pc.in
@@ -7,5 +7,5 @@ Name: libunwind
 Description: libunwind base library
 Version: @VERSION@
 Libs: -L${libdir} -lunwind
-Libs.private: @LIBLZMA@
+Libs.private: @LIBLZMA@ @LIBZ@
 Cflags: -I${includedir}