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From 1cfcf3004e1830f8fe9112cfcd15285508d2c2b7 Mon Sep 17 00:00:00 2001
From: Alan Modra <amodra@gmail.com>
Date: Thu, 11 Feb 2021 16:56:42 +1030
Subject: [PATCH] PR27290, PR27293, PR27295, various avr objdump fixes
Adds missing sanity checks for avr device info note, to avoid
potential buffer overflows. Uses bfd_malloc_and_get_section for
sanity checking section size.
PR 27290
PR 27293
PR 27295
* od-elf32_avr.c (elf32_avr_get_note_section_contents): Formatting.
Use bfd_malloc_and_get_section.
(elf32_avr_get_note_desc): Formatting. Return descsz. Sanity
check namesz. Return NULL if descsz is too small. Ensure
string table is terminated.
(elf32_avr_get_device_info): Formatting. Add note_size param.
Sanity check note.
(elf32_avr_dump_mem_usage): Adjust to suit.
Upstream-Status: Backport
CVE: CVE-2021-3549
Signed-of-by: Armin Kuster <akuster@mvista.com>
---
binutils/ChangeLog | 14 +++++++++
binutils/od-elf32_avr.c | 66 ++++++++++++++++++++++++++---------------
2 files changed, 56 insertions(+), 24 deletions(-)
Index: git/binutils/od-elf32_avr.c
===================================================================
--- git.orig/binutils/od-elf32_avr.c
+++ git/binutils/od-elf32_avr.c
@@ -77,23 +77,29 @@ elf32_avr_filter (bfd *abfd)
return bfd_get_flavour (abfd) == bfd_target_elf_flavour;
}
-static char*
+static char *
elf32_avr_get_note_section_contents (bfd *abfd, bfd_size_type *size)
{
asection *section;
+ bfd_byte *contents;
- if ((section = bfd_get_section_by_name (abfd, ".note.gnu.avr.deviceinfo")) == NULL)
+ section = bfd_get_section_by_name (abfd, ".note.gnu.avr.deviceinfo");
+ if (section == NULL)
return NULL;
- *size = bfd_section_size (section);
- char *contents = (char *) xmalloc (*size);
- bfd_get_section_contents (abfd, section, contents, 0, *size);
+ if (!bfd_malloc_and_get_section (abfd, section, &contents))
+ {
+ free (contents);
+ contents = NULL;
+ }
- return contents;
+ *size = bfd_section_size (section);
+ return (char *) contents;
}
-static char* elf32_avr_get_note_desc (bfd *abfd, char *contents,
- bfd_size_type size)
+static char *
+elf32_avr_get_note_desc (bfd *abfd, char *contents, bfd_size_type size,
+ bfd_size_type *descsz)
{
Elf_External_Note *xnp = (Elf_External_Note *) contents;
Elf_Internal_Note in;
@@ -107,42 +113,54 @@ static char* elf32_avr_get_note_desc (bf
if (in.namesz > contents - in.namedata + size)
return NULL;
+ if (in.namesz != 4 || strcmp (in.namedata, "AVR") != 0)
+ return NULL;
+
in.descsz = bfd_get_32 (abfd, xnp->descsz);
in.descdata = in.namedata + align_power (in.namesz, 2);
- if (in.descsz != 0
- && (in.descdata >= contents + size
- || in.descsz > contents - in.descdata + size))
+ if (in.descsz < 6 * sizeof (uint32_t)
+ || in.descdata >= contents + size
+ || in.descsz > contents - in.descdata + size)
return NULL;
- if (strcmp (in.namedata, "AVR") != 0)
- return NULL;
+ /* If the note has a string table, ensure it is 0 terminated. */
+ if (in.descsz > 8 * sizeof (uint32_t))
+ in.descdata[in.descsz - 1] = 0;
+ *descsz = in.descsz;
return in.descdata;
}
static void
elf32_avr_get_device_info (bfd *abfd, char *description,
- deviceinfo *device)
+ bfd_size_type desc_size, deviceinfo *device)
{
if (description == NULL)
return;
const bfd_size_type memory_sizes = 6;
- memcpy (device, description, memory_sizes * sizeof(uint32_t));
- device->name = NULL;
+ memcpy (device, description, memory_sizes * sizeof (uint32_t));
+ desc_size -= memory_sizes * sizeof (uint32_t);
+ if (desc_size < 8)
+ return;
- uint32_t *stroffset_table = ((uint32_t *) description) + memory_sizes;
+ uint32_t *stroffset_table = (uint32_t *) description + memory_sizes;
bfd_size_type stroffset_table_size = bfd_get_32 (abfd, stroffset_table);
- char *str_table = ((char *) stroffset_table) + stroffset_table_size;
/* If the only content is the size itself, there's nothing in the table */
- if (stroffset_table_size == 4)
+ if (stroffset_table_size < 8)
return;
+ if (desc_size <= stroffset_table_size)
+ return;
+ desc_size -= stroffset_table_size;
/* First entry is the device name index. */
uint32_t device_name_index = bfd_get_32 (abfd, stroffset_table + 1);
+ if (device_name_index >= desc_size)
+ return;
+ char *str_table = (char *) stroffset_table + stroffset_table_size;
device->name = str_table + device_name_index;
}
@@ -183,7 +201,7 @@ static void
elf32_avr_dump_mem_usage (bfd *abfd)
{
char *description = NULL;
- bfd_size_type note_section_size = 0;
+ bfd_size_type sec_size, desc_size;
deviceinfo device = { 0, 0, 0, 0, 0, 0, NULL };
device.name = "Unknown";
@@ -192,13 +210,13 @@ elf32_avr_dump_mem_usage (bfd *abfd)
bfd_size_type text_usage = 0;
bfd_size_type eeprom_usage = 0;
- char *contents = elf32_avr_get_note_section_contents (abfd,
- ¬e_section_size);
+ char *contents = elf32_avr_get_note_section_contents (abfd, &sec_size);
if (contents != NULL)
{
- description = elf32_avr_get_note_desc (abfd, contents, note_section_size);
- elf32_avr_get_device_info (abfd, description, &device);
+ description = elf32_avr_get_note_desc (abfd, contents, sec_size,
+ &desc_size);
+ elf32_avr_get_device_info (abfd, description, desc_size, &device);
}
elf32_avr_get_memory_usage (abfd, &text_usage, &data_usage,
Index: git/binutils/ChangeLog
===================================================================
--- git.orig/binutils/ChangeLog
+++ git/binutils/ChangeLog
@@ -1,3 +1,17 @@
+2021-02-11 Alan Modra <amodra@gmail.com>
+
+ PR 27290
+ PR 27293
+ PR 27295
+ * od-elf32_avr.c (elf32_avr_get_note_section_contents): Formatting.
+ Use bfd_malloc_and_get_section.
+ (elf32_avr_get_note_desc): Formatting. Return descsz. Sanity
+ check namesz. Return NULL if descsz is too small. Ensure
+ string table is terminated.
+ (elf32_avr_get_device_info): Formatting. Add note_size param.
+ Sanity check note.
+ (elf32_avr_dump_mem_usage): Adjust to suit.
+
2020-02-01 Nick Clifton <nickc@redhat.com>
* configure: Regenerate.
|
