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* [binutils-gdb] gdb: Fix out of bounds array access in buildsym_compunit::record_line
@ 2020-03-19 18:52 gdb-buildbot
  2020-03-19 18:52 ` Failures on Fedora-x86_64-cc-with-index, branch master gdb-buildbot
                   ` (6 more replies)
  0 siblings, 7 replies; 8+ messages in thread
From: gdb-buildbot @ 2020-03-19 18:52 UTC (permalink / raw)
  To: gdb-testers

*** TEST RESULTS FOR COMMIT dcc050c86c3e5160497da7aab480adae9ba284aa ***

commit dcc050c86c3e5160497da7aab480adae9ba284aa
Author:     Andrew Burgess <andrew.burgess@embecosm.com>
AuthorDate: Wed Mar 11 11:17:39 2020 +0000
Commit:     Andrew Burgess <andrew.burgess@embecosm.com>
CommitDate: Wed Mar 11 11:24:50 2020 +0000

    gdb: Fix out of bounds array access in buildsym_compunit::record_line
    
    This commit:
    
      commit 8c95582da858ac981f689a6f599acacb8c5c490f
      Date:   Mon Dec 30 21:04:51 2019 +0000
    
          gdb: Add support for tracking the DWARF line table is-stmt field
    
    Introduced an invalid memory access, by reading outside the bounds of
    an array.
    
    This would cause this valgrind error:
    
      ==7633== Invalid read of size 4
      ==7633==    at 0x4D002C: buildsym_compunit::record_line(subfile*, int, unsigned long, bool) (buildsym.c:688)
      ==7633==    by 0x5F60A5: dwarf_record_line_1(gdbarch*, subfile*, unsigned int, unsigned long, bool, dwarf2_cu*) (read.c:19956)
      ==7633==    by 0x5F63B0: lnp_state_machine::record_line(bool) (read.c:20024)
      ==7633==    by 0x5F5DD5: lnp_state_machine::handle_special_opcode(unsigned char) (read.c:19851)
      ==7633==    by 0x5F6706: dwarf_decode_lines_1(line_header*, dwarf2_cu*, int, unsigned long) (read.c:20135)
      ==7633==    by 0x5F6C57: dwarf_decode_lines(line_header*, char const*, dwarf2_cu*, dwarf2_psymtab*, unsigned long, int) (read.c:20328)
      ==7633==    by 0x5DF5F1: handle_DW_AT_stmt_list(die_info*, dwarf2_cu*, char const*, unsigned long) (read.c:10748)
      ==7633==    by 0x5DF823: read_file_scope(die_info*, dwarf2_cu*) (read.c:10796)
      ==7633==    by 0x5DDA63: process_die(die_info*, dwarf2_cu*) (read.c:9815)
      ==7633==    by 0x5DD44A: process_full_comp_unit(dwarf2_per_cu_data*, language) (read.c:9580)
      ==7633==    by 0x5DAB58: process_queue(dwarf2_per_objfile*) (read.c:8867)
      ==7633==    by 0x5CB30E: dw2_do_instantiate_symtab(dwarf2_per_cu_data*, bool) (read.c:2374)
      ==7633==  Address 0xa467f48 is 8 bytes before a block of size 16,024 alloc'd
      ==7633==    at 0x4C2CDCB: malloc (vg_replace_malloc.c:299)
      ==7633==    by 0x451FC4: xmalloc (alloc.c:60)
      ==7633==    by 0x4CFFDF: buildsym_compunit::record_line(subfile*, int, unsigned long, bool) (buildsym.c:678)
      ==7633==    by 0x5F60A5: dwarf_record_line_1(gdbarch*, subfile*, unsigned int, unsigned long, bool, dwarf2_cu*) (read.c:19956)
      ==7633==    by 0x5F63B0: lnp_state_machine::record_line(bool) (read.c:20024)
      ==7633==    by 0x5F5DD5: lnp_state_machine::handle_special_opcode(unsigned char) (read.c:19851)
      ==7633==    by 0x5F6706: dwarf_decode_lines_1(line_header*, dwarf2_cu*, int, unsigned long) (read.c:20135)
      ==7633==    by 0x5F6C57: dwarf_decode_lines(line_header*, char const*, dwarf2_cu*, dwarf2_psymtab*, unsigned long, int) (read.c:20328)
      ==7633==    by 0x5DF5F1: handle_DW_AT_stmt_list(die_info*, dwarf2_cu*, char const*, unsigned long) (read.c:10748)
      ==7633==    by 0x5DF823: read_file_scope(die_info*, dwarf2_cu*) (read.c:10796)
      ==7633==    by 0x5DDA63: process_die(die_info*, dwarf2_cu*) (read.c:9815)
      ==7633==    by 0x5DD44A: process_full_comp_unit(dwarf2_per_cu_data*, language) (read.c:9580)
    
    gdb/ChangeLog:
    
            * buildsyms.c (buildsym_compunit::record_line): Avoid accessing
            previous item in the list, when the list has no items.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 5c3d740a32..5e8fb71cd4 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-11  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* buildsyms.c (buildsym_compunit::record_line): Avoid accessing
+	previous item in the list, when the list has no items.
+
 2020-03-11  Tom de Vries  <tdevries@suse.de>
 
 	* dwarf2/loc.c (dwarf2_evaluate_property): Handle NULL frame in
diff --git a/gdb/buildsym.c b/gdb/buildsym.c
index 24aeba8e25..7155db34b0 100644
--- a/gdb/buildsym.c
+++ b/gdb/buildsym.c
@@ -681,15 +681,18 @@ buildsym_compunit::record_line (struct subfile *subfile, int line,
       m_have_line_numbers = true;
     }
 
-  /* If we have a duplicate for the previous entry then ignore the new
-     entry, except, if the new entry is setting the is_stmt flag, then
-     ensure the previous entry respects the new setting.  */
-  e = subfile->line_vector->item + subfile->line_vector->nitems - 1;
-  if (e->line == line && e->pc == pc)
+  if (subfile->line_vector->nitems > 0)
     {
-      if (is_stmt && !e->is_stmt)
-	e->is_stmt = 1;
-      return;
+      /* If we have a duplicate for the previous entry then ignore the new
+	 entry, except, if the new entry is setting the is_stmt flag, then
+	 ensure the previous entry respects the new setting.  */
+      e = subfile->line_vector->item + subfile->line_vector->nitems - 1;
+      if (e->line == line && e->pc == pc)
+	{
+	  if (is_stmt && !e->is_stmt)
+	    e->is_stmt = 1;
+	  return;
+	}
     }
 
   if (subfile->line_vector->nitems + 1 >= subfile->line_vector_length)


^ permalink raw reply	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-03-22 22:42 UTC | newest]

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2020-03-19 18:52 [binutils-gdb] gdb: Fix out of bounds array access in buildsym_compunit::record_line gdb-buildbot
2020-03-19 18:52 ` Failures on Fedora-x86_64-cc-with-index, branch master gdb-buildbot
2020-03-19 19:56 ` Failures on Fedora-x86_64-m64, " gdb-buildbot
2020-03-19 21:24 ` Failures on Fedora-x86_64-native-extended-gdbserver-m32, " gdb-buildbot
2020-03-19 22:02 ` Failures on Fedora-x86_64-native-extended-gdbserver-m64, " gdb-buildbot
2020-03-22  5:04 ` Failures on Fedora-x86_64-native-gdbserver-m64, " gdb-buildbot
2020-03-22 14:05 ` Failures on Ubuntu-Aarch64-native-extended-gdbserver-m64, " gdb-buildbot
2020-03-22 22:42 ` Failures on Fedora-x86_64-native-gdbserver-m32, " gdb-buildbot

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