--- /dev/null
+From aec72fda3b320c36eb99fc1c4cf95b10fc026729 Mon Sep 17 00:00:00 2001
+From: Alan Modra <amodra@gmail.com>
+Date: Thu, 16 Apr 2020 17:49:38 +0930
+Subject: [PATCH] PR25827, Null pointer dereferencing in scan_unit_for_symbols
+
+ PR 25827
+ * dwarf2.c (scan_unit_for_symbols): Wrap overlong lines. Don't
+ strdup(0).
+
+Upstream-Status: Backport
+https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=aec72fda3b320c36eb99fc1c4cf95b10fc026729
+CVE: CVE-2020-16593
+Signed-off-by: Armin Kuster <akuster@mvista.com>
+
+
+Index: git/bfd/dwarf2.c
+===================================================================
+--- git.orig/bfd/dwarf2.c
++++ git/bfd/dwarf2.c
+@@ -295,12 +295,12 @@ struct comp_unit
+ /* This data structure holds the information of an abbrev. */
+ struct abbrev_info
+ {
+- unsigned int number; /* Number identifying abbrev. */
+- enum dwarf_tag tag; /* DWARF tag. */
+- int has_children; /* Boolean. */
+- unsigned int num_attrs; /* Number of attributes. */
+- struct attr_abbrev *attrs; /* An array of attribute descriptions. */
+- struct abbrev_info *next; /* Next in chain. */
++ unsigned int number; /* Number identifying abbrev. */
++ enum dwarf_tag tag; /* DWARF tag. */
++ bfd_boolean has_children; /* TRUE if the abbrev has children. */
++ unsigned int num_attrs; /* Number of attributes. */
++ struct attr_abbrev * attrs; /* An array of attribute descriptions. */
++ struct abbrev_info * next; /* Next in chain. */
+ };
+
+ struct attr_abbrev
+@@ -1487,6 +1487,8 @@ struct varinfo
+ {
+ /* Pointer to previous variable in list of all variables */
+ struct varinfo *prev_var;
++ /* The offset of the varinfo from the start of the unit. */
++ bfd_uint64_t unit_offset;
+ /* Source location file name */
+ char *file;
+ /* Source location line number */
+@@ -1497,7 +1499,7 @@ struct varinfo
+ /* Where the symbol is defined */
+ asection *sec;
+ /* Is this a stack variable? */
+- unsigned int stack: 1;
++ bfd_boolean stack;
+ };
+
+ /* Return TRUE if NEW_LINE should sort after LINE. */
+@@ -2871,7 +2873,7 @@ lookup_symbol_in_variable_table (struct
+ struct varinfo* each;
+
+ for (each = unit->variable_table; each; each = each->prev_var)
+- if (each->stack == 0
++ if (! each->stack
+ && each->file != NULL
+ && each->name != NULL
+ && each->addr == addr
+@@ -3166,6 +3168,20 @@ read_rangelist (struct comp_unit *unit,
+ return TRUE;
+ }
+
++static struct varinfo *
++lookup_var_by_offset (bfd_uint64_t offset, struct varinfo * table)
++{
++ while (table)
++ {
++ if (table->unit_offset == offset)
++ return table;
++ table = table->prev_var;
++ }
++
++ return NULL;
++}
++
++
+ /* DWARF2 Compilation unit functions. */
+
+ /* Scan over each die in a comp. unit looking for functions to add
+@@ -3202,6 +3218,9 @@ scan_unit_for_symbols (struct comp_unit
+ bfd_vma low_pc = 0;
+ bfd_vma high_pc = 0;
+ bfd_boolean high_pc_relative = FALSE;
++ bfd_uint64_t current_offset;
++
++ current_offset = info_ptr - unit->info_ptr_unit;
+
+ /* PR 17512: file: 9f405d9d. */
+ if (info_ptr >= info_ptr_end)
+@@ -3234,12 +3253,13 @@ scan_unit_for_symbols (struct comp_unit
+ goto fail;
+ }
+
+- var = NULL;
+ if (abbrev->tag == DW_TAG_subprogram
+ || abbrev->tag == DW_TAG_entry_point
+ || abbrev->tag == DW_TAG_inlined_subroutine)
+ {
+ bfd_size_type amt = sizeof (struct funcinfo);
++
++ var = NULL;
+ func = (struct funcinfo *) bfd_zalloc (abfd, amt);
+ if (func == NULL)
+ goto fail;
+@@ -3268,13 +3288,15 @@ scan_unit_for_symbols (struct comp_unit
+ if (var == NULL)
+ goto fail;
+ var->tag = abbrev->tag;
+- var->stack = 1;
++ var->stack = TRUE;
+ var->prev_var = unit->variable_table;
+ unit->variable_table = var;
++ var->unit_offset = current_offset;
+ /* PR 18205: Missing debug information can cause this
+ var to be attached to an already cached unit. */
+ }
+-
++ else
++ var = NULL;
+ /* No inline function in scope at this nesting level. */
+ nested_funcs[nesting_level].func = 0;
+ }
+@@ -3362,6 +3384,33 @@ scan_unit_for_symbols (struct comp_unit
+ {
+ switch (attr.name)
+ {
++ case DW_AT_specification:
++ if (attr.u.val)
++ {
++ struct varinfo * spec_var;
++
++ spec_var = lookup_var_by_offset (attr.u.val,
++ unit->variable_table);
++ if (spec_var == NULL)
++ {
++ _bfd_error_handler (_("DWARF error: could not find "
++ "variable specification "
++ "at offset %lx"),
++ (unsigned long) attr.u.val);
++ break;
++ }
++
++ if (var->name == NULL)
++ var->name = spec_var->name;
++ if (var->file == NULL && spec_var->file != NULL)
++ var->file = strdup (spec_var->file);
++ if (var->line == 0)
++ var->line = spec_var->line;
++ if (var->sec == NULL)
++ var->sec = spec_var->sec;
++ }
++ break;
++
+ case DW_AT_name:
+ if (is_str_attr (attr.form))
+ var->name = attr.u.str;
+@@ -3378,7 +3427,7 @@ scan_unit_for_symbols (struct comp_unit
+
+ case DW_AT_external:
+ if (attr.u.val != 0)
+- var->stack = 0;
++ var->stack = FALSE;
+ break;
+
+ case DW_AT_location:
+@@ -3392,7 +3441,7 @@ scan_unit_for_symbols (struct comp_unit
+ if (attr.u.blk->data != NULL
+ && *attr.u.blk->data == DW_OP_addr)
+ {
+- var->stack = 0;
++ var->stack = FALSE;
+
+ /* Verify that DW_OP_addr is the only opcode in the
+ location, in which case the block size will be 1
+@@ -3888,7 +3937,7 @@ comp_unit_hash_info (struct dwarf2_debug
+ each_var = each_var->prev_var)
+ {
+ /* Skip stack vars and vars with no files or names. */
+- if (each_var->stack == 0
++ if (! each_var->stack
+ && each_var->file != NULL
+ && each_var->name != NULL)
+ /* There is no need to copy name string into hash table as
+Index: git/bfd/ChangeLog
+===================================================================
+--- git.orig/bfd/ChangeLog
++++ git/bfd/ChangeLog
+@@ -1,3 +1,9 @@
++2020-04-16 Alan Modra <amodra@gmail.com>
++
++ PR 25827
++ * dwarf2.c (scan_unit_for_symbols): Wrap overlong lines. Don't
++ strdup(0).
++
+ 2020-02-19 H.J. Lu <hongjiu.lu@intel.com>
+
+ PR binutils/25355
