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authorNick Clifton <nickc@redhat.com>2018-02-28 11:50:49 +0000
committerNick Clifton <nickc@redhat.com>2018-02-28 11:53:06 +0000
commit12c963421d045a127c413a0722062b9932c50aa9 (patch)
treec708ba5d2f686c3fec620cc676ce54f704478770 /bfd/dwarf2.c
parent116acb2c268c89c89186673a7c92620d21825b25 (diff)
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Catch integer overflows/underflows when parsing corrupt DWARF FORM blocks.
PR 22895 PR 22893 * dwarf2.c (read_n_bytes): Replace size parameter with dwarf_block pointer. Drop unused abfd parameter. Check the size of the block before initialising the data field. Return the end pointer if the size is invalid. (read_attribute_value): Adjust invocations of read_n_bytes.
Diffstat (limited to 'bfd/dwarf2.c')
-rw-r--r--bfd/dwarf2.c36
1 files changed, 21 insertions, 15 deletions
diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 2413542..ca22db7 100644
--- a/bfd/dwarf2.c
+++ b/bfd/dwarf2.c
@@ -623,14 +623,24 @@ read_8_bytes (bfd *abfd, bfd_byte *buf, bfd_byte *end)
}
static bfd_byte *
-read_n_bytes (bfd *abfd ATTRIBUTE_UNUSED,
- bfd_byte *buf,
- bfd_byte *end,
- unsigned int size ATTRIBUTE_UNUSED)
+read_n_bytes (bfd_byte * buf,
+ bfd_byte * end,
+ struct dwarf_block * block)
{
- if (buf + size > end)
- return NULL;
- return buf;
+ unsigned int size = block->size;
+ bfd_byte * block_end = buf + size;
+
+ if (block_end > end || block_end < buf)
+ {
+ block->data = NULL;
+ block->size = 0;
+ return end;
+ }
+ else
+ {
+ block->data = buf;
+ return block_end;
+ }
}
/* Scans a NUL terminated string starting at BUF, returning a pointer to it.
@@ -1128,8 +1138,7 @@ read_attribute_value (struct attribute * attr,
return NULL;
blk->size = read_2_bytes (abfd, info_ptr, info_ptr_end);
info_ptr += 2;
- blk->data = read_n_bytes (abfd, info_ptr, info_ptr_end, blk->size);
- info_ptr += blk->size;
+ info_ptr = read_n_bytes (info_ptr, info_ptr_end, blk);
attr->u.blk = blk;
break;
case DW_FORM_block4:
@@ -1139,8 +1148,7 @@ read_attribute_value (struct attribute * attr,
return NULL;
blk->size = read_4_bytes (abfd, info_ptr, info_ptr_end);
info_ptr += 4;
- blk->data = read_n_bytes (abfd, info_ptr, info_ptr_end, blk->size);
- info_ptr += blk->size;
+ info_ptr = read_n_bytes (info_ptr, info_ptr_end, blk);
attr->u.blk = blk;
break;
case DW_FORM_data2:
@@ -1180,8 +1188,7 @@ read_attribute_value (struct attribute * attr,
blk->size = _bfd_safe_read_leb128 (abfd, info_ptr, &bytes_read,
FALSE, info_ptr_end);
info_ptr += bytes_read;
- blk->data = read_n_bytes (abfd, info_ptr, info_ptr_end, blk->size);
- info_ptr += blk->size;
+ info_ptr = read_n_bytes (info_ptr, info_ptr_end, blk);
attr->u.blk = blk;
break;
case DW_FORM_block1:
@@ -1191,8 +1198,7 @@ read_attribute_value (struct attribute * attr,
return NULL;
blk->size = read_1_byte (abfd, info_ptr, info_ptr_end);
info_ptr += 1;
- blk->data = read_n_bytes (abfd, info_ptr, info_ptr_end, blk->size);
- info_ptr += blk->size;
+ info_ptr = read_n_bytes (info_ptr, info_ptr_end, blk);
attr->u.blk = blk;
break;
case DW_FORM_data1: