isofs: Fix unchecked printing of ER records

commit 4e20246 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 <[email protected]> Signed-off-by: Jan Kara <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
jiangmouren · Jan 8, 2015 · a3d4f59 · a3d4f59
1 parent e990e54
commit a3d4f59
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
@@ -362,6 +362,9 @@ parse_rock_ridge_inode_internal(struct iso_directory_record *de,
 			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: ");
 			{