From 12c963421d045a127c413a0722062b9932c50aa9 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Wed, 28 Feb 2018 11:50:49 +0000 Subject: [PATCH] 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. Upstream-Status: Backport Affects: <= 2.30 CVE: CVE-2018-7569 Signed-off-by: Armin Kuster --- bfd/ChangeLog | 8 ++++++++ bfd/dwarf2.c | 36 +++++++++++++++++++++--------------- 2 files changed, 29 insertions(+), 15 deletions(-) Index: git/bfd/dwarf2.c =================================================================== --- git.orig/bfd/dwarf2.c +++ git/bfd/dwarf2.c @@ -649,14 +649,24 @@ read_8_bytes (bfd *abfd, bfd_byte *buf, } static bfd_byte * -read_n_bytes (bfd *abfd ATTRIBUTE_UNUSED, - bfd_byte *buf, - bfd_byte *end, - unsigned int size ATTRIBUTE_UNUSED) -{ - if (buf + size > end) - return NULL; - return buf; +read_n_bytes (bfd_byte * buf, + bfd_byte * end, + struct dwarf_block * block) +{ + 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. @@ -1154,8 +1164,7 @@ read_attribute_value (struct attribute * 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: @@ -1165,8 +1174,7 @@ read_attribute_value (struct attribute * 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: @@ -1206,8 +1214,7 @@ read_attribute_value (struct attribute * 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: @@ -1217,8 +1224,7 @@ read_attribute_value (struct attribute * 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: Index: git/bfd/ChangeLog =================================================================== --- git.orig/bfd/ChangeLog +++ git/bfd/ChangeLog @@ -1,4 +1,14 @@ 2018-02-28 Nick Clifton + + 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. + +2018-02-28 Nick Clifton PR 22894 * dwarf1.c (parse_die): Check the length of form blocks before