CVE-2011-4086 jbd2: unmapped buffer with _Unwritten or _Delay flags set can lead to DoS (rhbz 788260)

This commit is contained in:
Josh Boyer 2012-02-08 08:37:23 -05:00
parent 49977fed11
commit 32e0cc2b97
2 changed files with 102 additions and 1 deletions

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@ -0,0 +1,91 @@
Path: news.gmane.org!not-for-mail
From: Eric Sandeen <sandeen@redhat.com>
Newsgroups: gmane.comp.file-systems.ext4
Subject: [PATCH] jbd2: clear BH_Delay & BH_Unwritten in journal_unmap_buffer
Date: Tue, 07 Feb 2012 16:07:20 -0600
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journal_unmap_buffer()'s zap_buffer: code clears a lot of buffer head
state ala discard_buffer(), but does not touch _Delay or _Unwritten
as discard_buffer() does.
This can be problematic in some areas of the ext4 code which assume
that if they have found a buffer marked unwritten or delay, then it's
a live one. Perhaps those spots should check whether it is mapped
as well, but if jbd2 is going to tear down a buffer, let's really
tear it down completely.
Without this I get some fsx failures on sub-page-block filesystems
up until v3.2, at which point 4e96b2dbbf1d7e81f22047a50f862555a6cb87cb
and 189e868fa8fdca702eb9db9d8afc46b5cb9144c9 make the failures go
away, because buried within that large change is some more flag
clearing. I still think it's worth doing in jbd2, since
->invalidatepage leads here directly, and it's the right place
to clear away these flags.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: stable@vger.kernel.org
---
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 35ae096..52653306 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1949,6 +1949,8 @@ zap_buffer_unlocked:
clear_buffer_mapped(bh);
clear_buffer_req(bh);
clear_buffer_new(bh);
+ clear_buffer_delay(bh);
+ clear_buffer_unwritten(bh);
bh->b_bdev = NULL;
return may_free;
}
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@ -54,7 +54,7 @@ Summary: The Linux kernel
# For non-released -rc kernels, this will be appended after the rcX and
# gitX tags, so a 3 here would become part of release "0.rcX.gitX.3"
#
%global baserelease 1
%global baserelease 2
%global fedora_build %{baserelease}
# base_sublevel is the kernel version we're starting with and patching
@ -743,6 +743,9 @@ Patch21094: power-x86-destdir.patch
Patch21095: hfsplus-Change-finder_info-to-u32.patch
Patch21096: hfsplus-Add-an-ioctl-to-bless-files.patch
#rhbz 788260
Patch21233: jbd2-clear-BH_Delay-and-BH_Unwritten-in-journal_unmap_buf.patch
# compat-wireless patches
Patch50000: compat-wireless-config-fixups.patch
Patch50001: compat-wireless-pr_fmt-warning-avoidance.patch
@ -1434,6 +1437,9 @@ ApplyPatch power-x86-destdir.patch
ApplyPatch hfsplus-Change-finder_info-to-u32.patch
ApplyPatch hfsplus-Add-an-ioctl-to-bless-files.patch
#rhbz 788269
ApplyPatch jbd2-clear-BH_Delay-and-BH_Unwritten-in-journal_unmap_buf.patch
# END OF PATCH APPLICATIONS
%endif
@ -2304,6 +2310,10 @@ fi
# ||----w |
# || ||
%changelog
* Wed Feb 08 2012 Josh Boyer <jwboyer@redhat.com>
- CVE-2011-4086 jbd2: unmapped buffer with _Unwritten or _Delay flags set can
lead to DoS (rhbz 788260)
* Tue Feb 07 2012 Josh Boyer <jwboyer@redhat.com>
- Linux 3.3-rc2-git6 (upstream 6bd113f1f4a8c0d05c4dbadb300319e0e3526db4)