* [binutils-gdb] bfd_close_all_done bug and bfd_last_cache
@ 2023-08-21 10:43 Alan Modra
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From: Alan Modra @ 2023-08-21 10:43 UTC (permalink / raw)
To: bfd-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=fa62aafb7d81b89d68752e830a757ef4199d0b21
commit fa62aafb7d81b89d68752e830a757ef4199d0b21
Author: Alan Modra <amodra@gmail.com>
Date: Mon Aug 21 18:38:08 2023 +0930
bfd_close_all_done bug and bfd_last_cache
bfd_close ought to always call iovec->bclose so that cache_bclose is
called. If not, bfd_last_cache will be left pointing at freed memory.
This bug was found by oss-fuzz with the trigger being an old bug in
the ia64-vms support. Given a file of the "wrong" size,
elf64_vms_close_and_cleanup attempted to extend it, leading to an
error since the file was opened read-only by nm. nm bad_file bad_file
then hit the use-after-free when opening the second file.
commit 8219cab3f8 fixed multiple bugs of this type in bfd_close and
bfd_close_all_done, but didn't go quite far enough.
* elf64-ia64-vms.c (elf64_vms_close_and_cleanup): Don't
attempt to extend read-only files.
* opncls.c (bfd_close_all_done): Always call _close_and_cleanup.
An old bug in the ia64-vms support can be used to tickle another bug
in bfd_close_all_done. If _close_and_cleanup returns an error,
Diff:
---
bfd/elf64-ia64-vms.c | 3 ++-
bfd/opncls.c | 10 ++++------
2 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/bfd/elf64-ia64-vms.c b/bfd/elf64-ia64-vms.c
index f8e9922fc4a..ab1f18b8d81 100644
--- a/bfd/elf64-ia64-vms.c
+++ b/bfd/elf64-ia64-vms.c
@@ -4713,7 +4713,8 @@ static bool
elf64_vms_close_and_cleanup (bfd *abfd)
{
bool ret = true;
- if (bfd_get_format (abfd) == bfd_object)
+ if (bfd_get_format (abfd) == bfd_object
+ && bfd_write_p (abfd))
{
long isize;
diff --git a/bfd/opncls.c b/bfd/opncls.c
index 56a90046b1a..741d20e81da 100644
--- a/bfd/opncls.c
+++ b/bfd/opncls.c
@@ -920,13 +920,11 @@ bfd_close_all_done (bfd *abfd)
{
bool ret = BFD_SEND (abfd, _close_and_cleanup, (abfd));
- if (ret && abfd->iovec != NULL)
- {
- ret = abfd->iovec->bclose (abfd) == 0;
+ if (abfd->iovec != NULL)
+ ret &= abfd->iovec->bclose (abfd) == 0;
- if (ret)
- _maybe_make_executable (abfd);
- }
+ if (ret)
+ _maybe_make_executable (abfd);
_bfd_delete_bfd (abfd);
free (_bfd_error_buf);
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