133 lines
4.4 KiB
Diff
133 lines
4.4 KiB
Diff
From 596245135106b2a965d809e272dc7c758afdc98f Mon Sep 17 00:00:00 2001
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From: Nick Clifton <nickc@redhat.com>
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Date: Wed, 21 Oct 2020 17:42:42 +0100
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Subject: [PATCH] Work around problem in DWARF decoding library which can
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result in attempts to read arbitrary bytes as if they were an LEB128 encoded
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value.
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* dwarf.c (skip_attr_bytes): Accept DWARF versions higher than 4
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when processing the DW_FORM_ref_addr form.
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Skip bytes in DW_FORM_block and DW_FORM_exprloc forms.
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Handle DW_FORM_indirect.
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(get_type_signedness): Allow a limited amount of recursion.
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Do not attempt to decode types that use the DW_FORM_ref_addr form.
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(read_and_display_attr_value): Do not attempt to decode types
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that use the DW_FORM_ref_addr form.
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---
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binutils/dwarf.c | 43 +++++++++++++++++++++++++------------------
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1 files changed, 25 insertions(+), 18 deletions(-)
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diff --git a/binutils/dwarf.c b/binutils/dwarf.c
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index e152b20438cc..c842aba6c1e7 100644
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--- a/binutils/dwarf.c
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+++ b/binutils/dwarf.c
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@@ -1868,7 +1868,7 @@ skip_attr_bytes (unsigned long form,
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case DW_FORM_ref_addr:
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if (dwarf_version == 2)
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SAFE_BYTE_GET_AND_INC (uvalue, data, pointer_size, end);
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- else if (dwarf_version == 3 || dwarf_version == 4)
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+ else if (dwarf_version > 2)
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SAFE_BYTE_GET_AND_INC (uvalue, data, offset_size, end);
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else
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return NULL;
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@@ -1920,6 +1920,7 @@ skip_attr_bytes (unsigned long form,
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case DW_FORM_ref8:
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case DW_FORM_data8:
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+ case DW_FORM_ref_sig8:
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data += 8;
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break;
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@@ -1934,6 +1935,7 @@ skip_attr_bytes (unsigned long form,
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case DW_FORM_block:
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case DW_FORM_exprloc:
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READ_ULEB (uvalue, data, end);
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+ data += uvalue;
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break;
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case DW_FORM_block1:
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@@ -1951,12 +1953,12 @@ skip_attr_bytes (unsigned long form,
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data += 4 + uvalue;
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break;
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- case DW_FORM_ref_sig8:
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- data += 8;
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- break;
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-
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case DW_FORM_indirect:
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- /* FIXME: Handle this form. */
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+ READ_ULEB (form, data, end);
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+ if (form == DW_FORM_implicit_const)
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+ SKIP_ULEB (data, end);
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+ return skip_attr_bytes (form, data, end, pointer_size, offset_size, dwarf_version, value_return);
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+
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default:
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return NULL;
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}
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@@ -1978,7 +1980,7 @@ get_type_signedness (unsigned char * start,
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dwarf_vma offset_size,
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int dwarf_version,
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bfd_boolean * is_signed,
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- bfd_boolean is_nested)
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+ unsigned int nesting)
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{
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unsigned long abbrev_number;
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abbrev_entry * entry;
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@@ -1997,6 +1999,14 @@ get_type_signedness (unsigned char * start,
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/* FIXME: Issue a warning ? */
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return;
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+#define MAX_NESTING 20
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+ if (nesting > MAX_NESTING)
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+ {
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+ /* FIXME: Warn - or is this expected ?
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+ NB/ We need to avoid infinite recursion. */
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+ return;
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+ }
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+
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for (attr = entry->first_attr;
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attr != NULL && attr->attribute;
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attr = attr->next)
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@@ -2019,16 +2029,12 @@ get_type_signedness (unsigned char * start,
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#endif
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case DW_AT_type:
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/* Recurse. */
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- if (is_nested)
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- {
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- /* FIXME: Warn - or is this expected ?
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- NB/ We need to avoid infinite recursion. */
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- return;
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- }
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if (uvalue >= (size_t) (end - start))
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return;
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- get_type_signedness (start, start + uvalue, end, pointer_size,
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- offset_size, dwarf_version, is_signed, TRUE);
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+ /* We cannot correctly process DW_FORM_ref_addr at the moment. */
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+ if (attr->form != DW_FORM_ref_addr)
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+ get_type_signedness (start, start + uvalue, end, pointer_size,
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+ offset_size, dwarf_version, is_signed, nesting + 1);
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break;
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case DW_AT_encoding:
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@@ -2206,7 +2212,6 @@ read_and_display_attr_value (unsigned long attribute,
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SAFE_BYTE_GET_AND_INC (uvalue, data, offset_size, end);
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else
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error (_("Internal error: DWARF version is not 2, 3 or 4.\n"));
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-
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break;
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case DW_FORM_addr:
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@@ -2663,8 +2668,10 @@ read_and_display_attr_value (unsigned long attribute,
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{
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bfd_boolean is_signed = FALSE;
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- get_type_signedness (start, start + uvalue, end, pointer_size,
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- offset_size, dwarf_version, & is_signed, FALSE);
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+ /* We cannot correctly process DW_FORM_ref_addr at the moment. */
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+ if (form != DW_FORM_ref_addr)
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+ get_type_signedness (start, start + uvalue, end, pointer_size,
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+ offset_size, dwarf_version, & is_signed, 0);
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level_type_signed[level] = is_signed;
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}
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break;
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