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clean-up readelf: simplify and flatten body of process_attributes
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- use find_section_by_type() instead of a for-loop.
- reindent the whole function accordingly.
- move declaration of variables nearer from their usage.
- prune else branch by using a goto in the error case.

diff --git a/binutils/readelf.c b/binutils/readelf.c
index 6d3ec65a8a1..878012da8f0 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -19268,42 +19268,32 @@ process_attributes (Filedata * filedata,
                    unsigned char * (* display_pub_attribute) (unsigned char *, const unsigned char * const),
                    unsigned char * (* display_proc_gnu_attribute) (unsigned char *, unsigned int, const unsigned char * const))
 {
-  Elf_Internal_Shdr * sect;
-  unsigned i;
-  bool res = true;
-
   /* Find the section header so that we get the size.  */
-  for (i = 0, sect = filedata->section_headers;
-       i < filedata->file_header.e_shnum;
-       i++, sect++)
-    {
-      unsigned char * contents;
-      unsigned char * p;
+  Elf_Internal_Shdr * sect = find_section_by_type (filedata, proc_type);
+  if (sect == NULL)
+    sect = find_section_by_type (filedata, SHT_GNU_ATTRIBUTES);

-      if (sect->sh_type != proc_type && sect->sh_type != SHT_GNU_ATTRIBUTES)
-       continue;
+  if (sect == NULL)
+    /* No section, exit without error.  */
+    return true;

-      contents = (unsigned char *) get_data (NULL, filedata, sect->sh_offset, 1,
-                                             sect->sh_size, _("attributes"));
+  unsigned char * contents = (unsigned char *)
+    get_data (NULL, filedata, sect->sh_offset, 1, sect->sh_size, _("attributes"));
   if (contents == NULL)
-       {
-         res = false;
-         continue;
-       }
+    return false;

-      p = contents;
+  bool res = true;
+  unsigned char * p = contents;
   /* The first character is the version of the attributes.
      Currently only version 1, (aka 'A') is recognised here.  */
   if (*p != 'A')
     {
       printf (_("Unknown attributes version '%c'(%d) - expecting 'A'\n"), *p, *p);
       res = false;
+      goto free_data;
     }
-      else
-       {
-         uint64_t section_len;

-         section_len = sect->sh_size - 1;
+  uint64_t section_len = sect->sh_size - 1;
   p++;

   while (section_len > 0)
@@ -19456,10 +19446,9 @@ process_attributes (Filedata * filedata,
            attr_len = 0;
        }
     }
-       }

+free_data:
   free (contents);
-    }

   return res;
 }
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Matthieu Longo committed Mar 4, 2025
1 parent 434a7a6 commit 3f8f380
Showing 1 changed file with 153 additions and 164 deletions.
317 changes: 153 additions & 164 deletions binutils/readelf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19271,199 +19271,188 @@ process_attributes (Filedata * filedata,
unsigned char * (* display_pub_attribute) (unsigned char *, const unsigned char * const),
unsigned char * (* display_proc_gnu_attribute) (unsigned char *, unsigned int, const unsigned char * const))
{
Elf_Internal_Shdr * sect;
unsigned i;
bool res = true;

/* Find the section header so that we get the size. */
for (i = 0, sect = filedata->section_headers;
i < filedata->file_header.e_shnum;
i++, sect++)
Elf_Internal_Shdr * sect = find_section_by_type (filedata, proc_type);
if (sect == NULL)
sect = find_section_by_type (filedata, SHT_GNU_ATTRIBUTES);

if (sect == NULL)
/* No section, exit without error. */
return true;

unsigned char * contents = (unsigned char *)
get_data (NULL, filedata, sect->sh_offset, 1, sect->sh_size, _("attributes"));
if (contents == NULL)
return false;

bool res = true;
unsigned char * p = contents;
/* The first character is the version of the attributes.
Currently only version 1, (aka 'A') is recognised here. */
if (*p != 'A')
{
unsigned char * contents;
unsigned char * p;
printf (_("Unknown attributes version '%c'(%d) - expecting 'A'\n"), *p, *p);
res = false;
goto free_data;
}

if (sect->sh_type != proc_type && sect->sh_type != SHT_GNU_ATTRIBUTES)
continue;
uint64_t section_len = sect->sh_size - 1;
p++;

while (section_len > 0)
{
uint64_t attr_len;
unsigned int namelen;
bool public_section;
bool gnu_section;

contents = (unsigned char *) get_data (NULL, filedata, sect->sh_offset, 1,
sect->sh_size, _("attributes"));
if (contents == NULL)
if (section_len <= 4)
{
error (_("Tag section ends prematurely\n"));
res = false;
continue;
break;
}
attr_len = byte_get (p, 4);
p += 4;

p = contents;
/* The first character is the version of the attributes.
Currently only version 1, (aka 'A') is recognised here. */
if (*p != 'A')
if (attr_len > section_len)
{
printf (_("Unknown attributes version '%c'(%d) - expecting 'A'\n"), *p, *p);
error (_("Bad attribute length (%u > %u)\n"),
(unsigned) attr_len, (unsigned) section_len);
attr_len = section_len;
res = false;
}
else
/* PR 17531: file: 001-101425-0.004 */
else if (attr_len < 5)
{
uint64_t section_len;
error (_("Attribute length of %u is too small\n"), (unsigned) attr_len);
res = false;
break;
}

section_len = sect->sh_size - 1;
p++;
section_len -= attr_len;
attr_len -= 4;

while (section_len > 0)
{
uint64_t attr_len;
unsigned int namelen;
bool public_section;
bool gnu_section;
namelen = strnlen ((char *) p, attr_len) + 1;
if (namelen == 0 || namelen >= attr_len)
{
error (_("Corrupt attribute section name\n"));
res = false;
break;
}

if (section_len <= 4)
{
error (_("Tag section ends prematurely\n"));
res = false;
break;
}
attr_len = byte_get (p, 4);
p += 4;
printf (_("Attribute Section: "));
print_symbol_name (INT_MAX, (const char *) p);
putchar ('\n');

if (attr_len > section_len)
{
error (_("Bad attribute length (%u > %u)\n"),
(unsigned) attr_len, (unsigned) section_len);
attr_len = section_len;
res = false;
}
/* PR 17531: file: 001-101425-0.004 */
else if (attr_len < 5)
{
error (_("Attribute length of %u is too small\n"), (unsigned) attr_len);
res = false;
break;
}
if (public_name && streq ((char *) p, public_name))
public_section = true;
else
public_section = false;

section_len -= attr_len;
attr_len -= 4;
if (streq ((char *) p, "gnu"))
gnu_section = true;
else
gnu_section = false;

namelen = strnlen ((char *) p, attr_len) + 1;
if (namelen == 0 || namelen >= attr_len)
{
error (_("Corrupt attribute section name\n"));
res = false;
break;
}
p += namelen;
attr_len -= namelen;

printf (_("Attribute Section: "));
print_symbol_name (INT_MAX, (const char *) p);
putchar ('\n');
while (attr_len > 0 && p < contents + sect->sh_size)
{
int tag;
unsigned int val;
uint64_t size;
unsigned char * end;

if (public_name && streq ((char *) p, public_name))
public_section = true;
else
public_section = false;
/* PR binutils/17531: Safe handling of corrupt files. */
if (attr_len < 6)
{
error (_("Unused bytes at end of section\n"));
res = false;
section_len = 0;
break;
}

if (streq ((char *) p, "gnu"))
gnu_section = true;
else
gnu_section = false;
tag = *(p++);
size = byte_get (p, 4);
if (size > attr_len)
{
error (_("Bad subsection length (%u > %u)\n"),
(unsigned) size, (unsigned) attr_len);
res = false;
size = attr_len;
}
/* PR binutils/17531: Safe handling of corrupt files. */
if (size < 6)
{
error (_("Bad subsection length (%u < 6)\n"),
(unsigned) size);
res = false;
section_len = 0;
break;
}

p += namelen;
attr_len -= namelen;
attr_len -= size;
end = p + size - 1;
assert (end <= contents + sect->sh_size);
p += 4;

while (attr_len > 0 && p < contents + sect->sh_size)
switch (tag)
{
case 1:
printf (_("File Attributes\n"));
break;
case 2:
printf (_("Section Attributes:"));
goto do_numlist;
case 3:
printf (_("Symbol Attributes:"));
/* Fall through. */
do_numlist:
for (;;)
{
int tag;
unsigned int val;
uint64_t size;
unsigned char * end;

/* PR binutils/17531: Safe handling of corrupt files. */
if (attr_len < 6)
{
error (_("Unused bytes at end of section\n"));
res = false;
section_len = 0;
break;
}

tag = *(p++);
size = byte_get (p, 4);
if (size > attr_len)
{
error (_("Bad subsection length (%u > %u)\n"),
(unsigned) size, (unsigned) attr_len);
res = false;
size = attr_len;
}
/* PR binutils/17531: Safe handling of corrupt files. */
if (size < 6)
{
error (_("Bad subsection length (%u < 6)\n"),
(unsigned) size);
res = false;
section_len = 0;
break;
}

attr_len -= size;
end = p + size - 1;
assert (end <= contents + sect->sh_size);
p += 4;

switch (tag)
{
case 1:
printf (_("File Attributes\n"));
break;
case 2:
printf (_("Section Attributes:"));
goto do_numlist;
case 3:
printf (_("Symbol Attributes:"));
/* Fall through. */
do_numlist:
for (;;)
{
READ_ULEB (val, p, end);
if (val == 0)
break;
printf (" %d", val);
}
printf ("\n");
break;
default:
printf (_("Unknown tag: %d\n"), tag);
public_section = false;
break;
}

if (public_section && display_pub_attribute != NULL)
{
while (p < end)
p = display_pub_attribute (p, end);
assert (p == end);
}
else if (gnu_section && display_proc_gnu_attribute != NULL)
{
while (p < end)
p = display_gnu_attribute (p,
display_proc_gnu_attribute,
end);
assert (p == end);
}
else if (p < end)
{
printf (_(" Unknown attribute:\n"));
display_raw_attribute (p, end);
p = end;
}
else
attr_len = 0;
READ_ULEB (val, p, end);
if (val == 0)
break;
printf (" %d", val);
}
printf ("\n");
break;
default:
printf (_("Unknown tag: %d\n"), tag);
public_section = false;
break;
}
}

free (contents);
if (public_section && display_pub_attribute != NULL)
{
while (p < end)
p = display_pub_attribute (p, end);
assert (p == end);
}
else if (gnu_section && display_proc_gnu_attribute != NULL)
{
while (p < end)
p = display_gnu_attribute (p,
display_proc_gnu_attribute,
end);
assert (p == end);
}
else if (p < end)
{
printf (_(" Unknown attribute:\n"));
display_raw_attribute (p, end);
p = end;
}
else
attr_len = 0;
}
}

free_data:
free (contents);

return res;
}

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