[kernel/f20] CVE-2014-7975 fs: umount DoS (rhbz 1151108 1152025)

[Josh Boyer]

commit 3b14b07627ae59d7372ea09862f3e76cd32f134e
Author: Josh Boyer <jwboyer at fedoraproject.org>
Date:   Mon Oct 13 14:48:25 2014 -0400

    CVE-2014-7975 fs: umount DoS (rhbz 1151108 1152025)

 ...d-a-missing-permission-check-to-do_umount.patch |   31 ++++++++++++++++++++
 kernel.spec                                        |    9 ++++++
 2 files changed, 40 insertions(+), 0 deletions(-)
---
diff --git a/fs-Add-a-missing-permission-check-to-do_umount.patch b/fs-Add-a-missing-permission-check-to-do_umount.patch
new file mode 100644
index 0000000..ce9de66
--- /dev/null
+++ b/fs-Add-a-missing-permission-check-to-do_umount.patch
@@ -0,0 +1,31 @@
+From: Andy Lutomirski <luto at amacapital.net>
+Date: Wed, 8 Oct 2014 12:37:46 -0700
+Subject: [PATCH] fs: Add a missing permission check to do_umount
+
+Accessing do_remount_sb should require global CAP_SYS_ADMIN, but
+only one of the two call sites was appropriately protected.
+
+Fixes CVE-2014-7975.
+
+Cc: stable at vger.kernel.org
+Signed-off-by: Andy Lutomirski <luto at amacapital.net>
+---
+ fs/namespace.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/fs/namespace.c b/fs/namespace.c
+index c8e3034ff4b2..fbba8b17330d 100644
+--- a/fs/namespace.c
++++ b/fs/namespace.c
+@@ -1439,6 +1439,8 @@ static int do_umount(struct mount *mnt, int flags)
+ 		 * Special case for "unmounting" root ...
+ 		 * we just try to remount it readonly.
+ 		 */
++		if (!capable(CAP_SYS_ADMIN))
++			return -EPERM;
+ 		down_write(&sb->s_umount);
+ 		if (!(sb->s_flags & MS_RDONLY))
+ 			retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
+-- 
+1.9.3
+
diff --git a/kernel.spec b/kernel.spec
index 2701c51..f7a4888 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -733,6 +733,9 @@ Patch26039: HID-usbhid-always-poll-quirk-for-Elan-Touchscreen-00.patch
 Patch26040: USB-quirks-device-qualifier-quirk-for-another-Elan-t.patch
 Patch26041: HID-usbhid-always-poll-quirk-for-Elan-Touchscreen-01.patch
 
+#CVE-2014-7975 rhbz 1151108 1152025
+Patch26042: fs-Add-a-missing-permission-check-to-do_umount.patch
+
 # git clone ssh://git.fedorahosted.org/git/kernel-arm64.git, git diff master...devel
 Patch30000: kernel-arm64.patch
 
@@ -1434,6 +1437,9 @@ ApplyPatch HID-usbhid-always-poll-quirk-for-Elan-Touchscreen-00.patch
 ApplyPatch USB-quirks-device-qualifier-quirk-for-another-Elan-t.patch
 ApplyPatch HID-usbhid-always-poll-quirk-for-Elan-Touchscreen-01.patch
 
+#CVE-2014-7975 rhbz 1151108 1152025
+ApplyPatch fs-Add-a-missing-permission-check-to-do_umount.patch
+
 %if 0%{?aarch64patches}
 ApplyPatch kernel-arm64.patch
 %ifnarch aarch64 # this is stupid, but i want to notice before secondary koji does.
@@ -2252,6 +2258,9 @@ fi
 #                 ||----w |
 #                 ||     ||
 %changelog
+* Mon Oct 13 2014 Josh Boyer <jwboyer at fedoraproject.org>
+- CVE-2014-7975 fs: umount DoS (rhbz 1151108 1152025)
+
 * Sat Oct 11 2014 Josh Boyer <jwboyer at fedoraproject.org>
 - Add patches to fix elantech touchscreens (rhbz 1149509)