[CVE-2014-9584][Precise][Lucid] isofs: Fix unchecked printing of ER records

[Luis Henriques]

From: Jan Kara <jack at suse.cz>

We didn't check length of rock ridge ER records before printing them.
Thus corrupted isofs image can cause us to access and print some memory
behind the buffer with obvious consequences.

Reported-and-tested-by: Carl Henrik Lunde <chlunde at ping.uio.no>
CC: stable at vger.kernel.org
Signed-off-by: Jan Kara <jack at suse.cz>
(cherry picked from commit 4e2024624e678f0ebb916e6192bd23c1f9fdf696)
CVE-2014-9584
BugLink: http://bugs.launchpad.net/bugs/1409808
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/isofs/rock.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index 69c737d4b517..2ec72aeae9ca 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -363,6 +363,9 @@ repeat:
 			rs.cont_size = isonum_733(rr->u.CE.size);
 			break;
 		case SIG('E', 'R'):
+			/* Invalid length of ER tag id? */
+			if (rr->u.ER.len_id + offsetof(struct rock_ridge, u.ER.data) > rr->len)
+				goto out;
 			ISOFS_SB(inode->i_sb)->s_rock = 1;
 			printk(KERN_DEBUG "ISO 9660 Extensions: ");
 			{
-- 
2.1.4