yggdrasil/binutils-gdb
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asan: heap buffer overflow in mmo_scan

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mmo_get_loc needs to handle arbitrary vma and size chunks.  Fuzzers
found that it wasn't working so well when the end of chunks were
getting close to address wrap-around.

	* mmo.c (mmo_get_loc): Make "size" unsigned.  Avoid arithmetic
	overflow when calculating whether range hits an existing chunk.
This commit is contained in:
Alan Modra 2022-08-17 15:43:25 +09:30
parent 11c6a7c623
commit 2bda15d73c
1 changed files with 14 additions and 12 deletions
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26
bfd/mmo.c
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@ -382,7 +382,7 @@ static bool mmo_scan (bfd *);
static asection *mmo_decide_section (bfd *, bfd_vma);
static asection *mmo_get_generic_spec_data_section (bfd *, int);
static asection *mmo_get_spec_section (bfd *, int);
static bfd_byte *mmo_get_loc (asection *, bfd_vma, int);
static bfd_byte *mmo_get_loc (asection *, bfd_vma, unsigned int);
static bfd_cleanup mmo_object_p (bfd *);
static void mmo_map_set_sizes (bfd *, asection *, void *);
static bool mmo_get_symbols (bfd *);
@ -1492,7 +1492,7 @@ SUBSECTION
MMO_SEC_CONTENTS_CHUNK_SIZE. */
static bfd_byte *
mmo_get_loc (asection *sec, bfd_vma vma, int size)
mmo_get_loc (asection *sec, bfd_vma vma, unsigned int size)
{
bfd_size_type allocated_size;
struct mmo_section_data_struct *sdatap = mmo_section_data (sec);
@ -1504,27 +1504,29 @@ mmo_get_loc (asection *sec, bfd_vma vma, int size)
for (; datap != NULL; datap = datap->next)
{
if (datap->where <= vma
&& datap->where + datap->size >= vma + size)
return datap->data + vma - datap->where;
&& datap->size >= size
&& datap->size - size >= vma - datap->where)
return datap->data + (vma - datap->where);
else if (datap->where <= vma
&& datap->where + datap->allocated_size >= vma + size
&& datap->allocated_size >= size
&& datap->allocated_size - size >= vma - datap->where
/* Only munch on the "allocated size" if it does not
overlap the next chunk. */
&& (datap->next == NULL || datap->next->where >= vma + size))
{
/* There was room allocated, but the size wasn't set to include
it. Do that now. */
datap->size += (vma + size) - (datap->where + datap->size);
datap->size = vma - datap->where + size;
/* Update the section size. This happens only if we update the
32-bit-aligned chunk size. Callers that have
non-32-bit-aligned sections should do all allocation and
size-setting by themselves or at least set the section size
after the last allocating call to this function. */
if (vma + size > sec->vma + sec->size)
sec->size += (vma + size) - (sec->vma + sec->size);
if (vma - sec->vma + size > sec->size)
sec->size = vma - sec->vma + size;
return datap->data + vma - datap->where;
return datap->data + (vma - datap->where);
}
}
@ -1535,7 +1537,7 @@ mmo_get_loc (asection *sec, bfd_vma vma, int size)
for no more than MMO_SEC_CONTENTS_CHUNK_SIZE will always get resolved. */
for (datap = sdatap->head; datap != NULL; datap = datap->next)
if ((datap->where <= vma && datap->where + datap->size > vma)
if ((datap->where <= vma && datap->size > vma - datap->where)
|| (datap->where < vma + size
&& datap->where + datap->size >= vma + size))
return NULL;
@ -1583,8 +1585,8 @@ mmo_get_loc (asection *sec, bfd_vma vma, int size)
/* Update the section size. This happens only when we add contents and
re-size as we go. The section size will then be aligned to 32 bits. */
if (vma + size > sec->vma + sec->size)
sec->size += (vma + size) - (sec->vma + sec->size);
if (vma - sec->vma + size > sec->size)
sec->size = vma - sec->vma + size;
return entry->data;
}