[PATCH 3.4 070/176] isofs: Fix unchecked printing of ER records

[lizf]

From: Jan Kara <jack@xxxxxxx>

3.4.107-rc1 review patch.  If anyone has any objections, please let me know.

------------------


commit 4e2024624e678f0ebb916e6192bd23c1f9fdf696 upstream.

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@xxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
---
 fs/isofs/rock.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index 26859de..1780949 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -362,6 +362,9 @@ 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: ");
 			{
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/