rpms/kernel/F-11 fs-pipe-null-ptr-deref-fix.patch, NONE, 1.1 kernel.spec, 1.1774, 1.1775
Kyle McMartin
kyle at fedoraproject.org
Wed Nov 4 03:54:25 UTC 2009
Author: kyle
Update of /cvs/pkgs/rpms/kernel/F-11
In directory cvs1.fedora.phx.redhat.com:/tmp/cvs-serv23670
Modified Files:
kernel.spec
Added Files:
fs-pipe-null-ptr-deref-fix.patch
Log Message:
* Tue Nov 03 2009 Kyle McMartin <kyle at redhat.com> 2.6.30.9-96
- fs/pipe.c: fix null pointer dereference (CVE-2009-3547)
fs-pipe-null-ptr-deref-fix.patch:
pipe.c | 42 ++++++++++++++++++++++++++++++------------
1 file changed, 30 insertions(+), 12 deletions(-)
--- NEW FILE fs-pipe-null-ptr-deref-fix.patch ---
>From ad3960243e55320d74195fb85c975e0a8cc4466c Mon Sep 17 00:00:00 2001
From: Earl Chew <earl_chew at agilent.com>
Date: Mon, 19 Oct 2009 15:55:41 -0700
Subject: [PATCH] fs: pipe.c null pointer dereference
This patch fixes a null pointer exception in pipe_rdwr_open() which
generates the stack trace:
> Unable to handle kernel NULL pointer dereference at 0000000000000028 RIP:
> [<ffffffff802899a5>] pipe_rdwr_open+0x35/0x70
> [<ffffffff8028125c>] __dentry_open+0x13c/0x230
> [<ffffffff8028143d>] do_filp_open+0x2d/0x40
> [<ffffffff802814aa>] do_sys_open+0x5a/0x100
> [<ffffffff8021faf3>] sysenter_do_call+0x1b/0x67
The failure mode is triggered by an attempt to open an anonymous
pipe via /proc/pid/fd/* as exemplified by this script:
=============================================================
while : ; do
{ echo y ; sleep 1 ; } | { while read ; do echo z$REPLY; done ; } &
PID=$!
OUT=$(ps -efl | grep 'sleep 1' | grep -v grep |
{ read PID REST ; echo $PID; } )
OUT="${OUT%% *}"
DELAY=$((RANDOM * 1000 / 32768))
usleep $((DELAY * 1000 + RANDOM % 1000 ))
echo n > /proc/$OUT/fd/1 # Trigger defect
done
=============================================================
Note that the failure window is quite small and I could only
reliably reproduce the defect by inserting a small delay
in pipe_rdwr_open(). For example:
static int
pipe_rdwr_open(struct inode *inode, struct file *filp)
{
msleep(100);
mutex_lock(&inode->i_mutex);
Although the defect was observed in pipe_rdwr_open(), I think it
makes sense to replicate the change through all the pipe_*_open()
functions.
The core of the change is to verify that inode->i_pipe has not
been released before attempting to manipulate it. If inode->i_pipe
is no longer present, return ENOENT to indicate so.
The comment about potentially using atomic_t for i_pipe->readers
and i_pipe->writers has also been removed because it is no longer
relevant in this context. The inode->i_mutex lock must be used so
that inode->i_pipe can be dealt with correctly.
Signed-off-by: Earl Chew <earl_chew at agilent.com>
Cc: stable at kernel.org
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
---
fs/pipe.c | 41 ++++++++++++++++++++++++++++++-----------
1 files changed, 30 insertions(+), 11 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index 52c4151..ae17d02 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -777,36 +777,55 @@ pipe_rdwr_release(struct inode *inode, struct file *filp)
static int
pipe_read_open(struct inode *inode, struct file *filp)
{
- /* We could have perhaps used atomic_t, but this and friends
- below are the only places. So it doesn't seem worthwhile. */
+ int ret = -ENOENT;
+
mutex_lock(&inode->i_mutex);
- inode->i_pipe->readers++;
+
+ if (inode->i_pipe) {
+ ret = 0;
+ inode->i_pipe->readers++;
+ }
+
mutex_unlock(&inode->i_mutex);
- return 0;
+ return ret;
}
static int
pipe_write_open(struct inode *inode, struct file *filp)
{
+ int ret = -ENOENT;
+
mutex_lock(&inode->i_mutex);
- inode->i_pipe->writers++;
+
+ if (inode->i_pipe) {
+ ret = 0;
+ inode->i_pipe->writers++;
+ }
+
mutex_unlock(&inode->i_mutex);
- return 0;
+ return ret;
}
static int
pipe_rdwr_open(struct inode *inode, struct file *filp)
{
+ int ret = -ENOENT;
+
mutex_lock(&inode->i_mutex);
- if (filp->f_mode & FMODE_READ)
- inode->i_pipe->readers++;
- if (filp->f_mode & FMODE_WRITE)
- inode->i_pipe->writers++;
+
+ if (inode->i_pipe) {
+ ret = 0;
+ if (filp->f_mode & FMODE_READ)
+ inode->i_pipe->readers++;
+ if (filp->f_mode & FMODE_WRITE)
+ inode->i_pipe->writers++;
+ }
+
mutex_unlock(&inode->i_mutex);
- return 0;
+ return ret;
}
/*
--
1.6.5.1
Index: kernel.spec
===================================================================
RCS file: /cvs/pkgs/rpms/kernel/F-11/kernel.spec,v
retrieving revision 1.1774
retrieving revision 1.1775
diff -u -p -r1.1774 -r1.1775
--- kernel.spec 25 Oct 2009 10:45:32 -0000 1.1774
+++ kernel.spec 4 Nov 2009 03:54:25 -0000 1.1775
@@ -829,6 +829,10 @@ Patch16430: kvm-prevent-overflow-in-kvm-
# disable the stackprotector on fns that don't have onstack arrays
Patch16440: disable-stackprotector-all.patch
+# fs/pipe.c: null ptr dereference fix
+# rhbz#530490 (CVE-2009-3547) [ad3960243e55320d74195fb85c975e0a8cc4466c]
+Patch16450: fs-pipe-null-ptr-deref-fix.patch
+
%endif
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@@ -1555,6 +1559,10 @@ ApplyPatch kvm-prevent-overflow-in-kvm-g
# disable the stackprotector on fns that don't have onstack arrays
ApplyPatch disable-stackprotector-all.patch
+# fs/pipe.c: null ptr dereference fix
+# rhbz#530490 (CVE-2009-3547) [ad3960243e55320d74195fb85c975e0a8cc4466c]
+ApplyPatch fs-pipe-null-ptr-deref-fix.patch
+
# END OF PATCH APPLICATIONS
%endif
@@ -2143,6 +2151,9 @@ fi
# and build.
%changelog
+* Tue Nov 03 2009 Kyle McMartin <kyle at redhat.com> 2.6.30.9-96
+- fs/pipe.c: fix null pointer dereference (CVE-2009-3547)
+
* Sun Oct 25 2009 Chuck Ebbert <cebbert at redhat.com> 2.6.30.9-95
- Disable the stack protector on functions that don't have onstack arrays.
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