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CVE-2012-1090 CIFS: fix dentry refcount leak when opening a FIFO on lookup (rhbz 798296)

This commit is contained in:
Justin M. Forbes 2012-02-28 14:05:39 -06:00
parent 853703eece
commit 5c51b136d3
2 changed files with 71 additions and 1 deletions
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61
cifs-fix-dentry-refcount-leak-when-opening-a-FIFO.patch Normal file
View File

@ -0,0 +1,61 @@
From 5bccda0ebc7c0331b81ac47d39e4b920b198b2cd Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@redhat.com>
Date: Thu, 23 Feb 2012 09:37:45 -0500
Subject: [PATCH] cifs: fix dentry refcount leak when opening a FIFO on lookup
The cifs code will attempt to open files on lookup under certain
circumstances. What happens though if we find that the file we opened
was actually a FIFO or other special file?
Currently, the open filehandle just ends up being leaked leading to
a dentry refcount mismatch and oops on umount. Fix this by having the
code close the filehandle on the server if it turns out not to be a
regular file. While we're at it, change this spaghetti if statement
into a switch too.
Cc: stable@vger.kernel.org
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
---
fs/cifs/dir.c | 20 ++++++++++++++++++--
1 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 63a196b..bc7e244 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -584,10 +584,26 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
* If either that or op not supported returned, follow
* the normal lookup.
*/
- if ((rc == 0) || (rc == -ENOENT))
+ switch (rc) {
+ case 0:
+ /*
+ * The server may allow us to open things like
+ * FIFOs, but the client isn't set up to deal
+ * with that. If it's not a regular file, just
+ * close it and proceed as if it were a normal
+ * lookup.
+ */
+ if (newInode && !S_ISREG(newInode->i_mode)) {
+ CIFSSMBClose(xid, pTcon, fileHandle);
+ break;
+ }
+ case -ENOENT:
posix_open = true;
- else if ((rc == -EINVAL) || (rc != -EOPNOTSUPP))
+ case -EOPNOTSUPP:
+ break;
+ default:
pTcon->broken_posix_open = true;
+ }
}
if (!posix_open)
rc = cifs_get_inode_info_unix(&newInode, full_path,
--
1.7.0.4

11
kernel.spec
View File

@ -42,7 +42,7 @@ Summary: The Linux kernel
# When changing real_sublevel below, reset this by hand to 1
# (or to 0 and then use rpmdev-bumpspec).
#
%global baserelease 2
%global baserelease 3
%global fedora_build %{baserelease}
# real_sublevel is the 3.x kernel version we're starting with
@ -718,6 +718,9 @@ Patch21101: hpsa-add-irqf-shared.patch
#rhbz 727865 730007
Patch21102: ACPICA-Fix-regression-in-FADT-revision-checks.patch
# rhbz 798296
Patch21103: cifs-fix-dentry-refcount-leak-when-opening-a-FIFO.patch
%endif
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@ -1327,6 +1330,9 @@ ApplyPatch bcma-brcmsmac-compat.patch
#rhbz 727865 730007
ApplyPatch ACPICA-Fix-regression-in-FADT-revision-checks.patch
# rhbz 798296
ApplyPatch cifs-fix-dentry-refcount-leak-when-opening-a-FIFO.patch
# END OF PATCH APPLICATIONS
%endif
@ -1974,6 +1980,9 @@ fi
# and build.
%changelog
* Tue Feb 28 2012 Justin M. Forbes <jforbes@redhat.com> 2.6.42.7-3
- CVE-2012-1090 CIFS: fix dentry refcount leak when opening a FIFO on lookup (rhbz 798296)
* Mon Feb 27 2012 Josh Boyer <jwboyer@redhat.com>
- Add patch to fix regression in FADT revision checks (rhbz 730007 727865)