From 647cebce12a6b0a26960220caff96ff38978cf24 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Thu, 26 Nov 2020 17:08:33 +0000 Subject: [PATCH] Prevent a memory allocation failure when parsing corrupt DWARF debug sections. PR 26946 * dwarf2.c (read_section): Check for debug sections with excessive sizes. Upstream-Status: Backport [ https://sourceware.org/git/?p=binutils-gdb.git;a=patch;h=647cebce12a6b0a26960220caff96ff38978cf24 ] CVE: CVE-2021-3487 Signed-off-by: Chee Yang Lee --- bfd/dwarf2.c | 25 +++++++++++++++++++------ 1 files changed, 25 insertions(+), 6 deletions(-) diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c index 977bf43a6a1..8bbfc81d3e7 100644 --- a/bfd/dwarf2.c +++ b/bfd/dwarf2.c @@ -531,22 +531,24 @@ read_section (bfd * abfd, bfd_byte ** section_buffer, bfd_size_type * section_size) { - asection *msec; const char *section_name = sec->uncompressed_name; bfd_byte *contents = *section_buffer; - bfd_size_type amt; /* The section may have already been read. */ if (contents == NULL) { + bfd_size_type amt; + asection *msec; + ufile_ptr filesize; + msec = bfd_get_section_by_name (abfd, section_name); - if (! msec) + if (msec == NULL) { section_name = sec->compressed_name; if (section_name != NULL) msec = bfd_get_section_by_name (abfd, section_name); } - if (! msec) + if (msec == NULL) { _bfd_error_handler (_("DWARF error: can't find %s section."), sec->uncompressed_name); @@ -554,12 +556,23 @@ read_section (bfd * abfd, return FALSE; } - *section_size = msec->rawsize ? msec->rawsize : msec->size; + amt = bfd_get_section_limit_octets (abfd, msec); + filesize = bfd_get_file_size (abfd); + if (amt >= filesize) + { + /* PR 26946 */ + _bfd_error_handler (_("DWARF error: section %s is larger than its filesize! (0x%lx vs 0x%lx)"), + section_name, (long) amt, (long) filesize); + bfd_set_error (bfd_error_bad_value); + return FALSE; + } + *section_size = amt; /* Paranoia - alloc one extra so that we can make sure a string section is NUL terminated. */ - amt = *section_size + 1; + amt += 1; if (amt == 0) { + /* Paranoia - this should never happen. */ bfd_set_error (bfd_error_no_memory); return FALSE; } -- 2.27.0