isofs: Fix off-by-one in 'session' mount option parsing

According to ECMA-130 standard maximum valid track number is 99. Since
'session' mount option starts indexing at 0 (and we add 1 to the passed
number), we should refuse value 99. Also the condition in
isofs_get_last_session() unnecessarily repeats the check - remove it.

Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2017-07-18 12:27:56 +02:00
parent fcea8aed91
commit 34363c057b

View File

@ -410,7 +410,11 @@ static int parse_options(char *options, struct iso9660_options *popt)
if (match_int(&args[0], &option))
return 0;
n = option;
if (n > 99)
/*
* Track numbers are supposed to be in range 1-99, the
* mount option starts indexing at 0.
*/
if (n >= 99)
return 0;
popt->session = n + 1;
break;
@ -543,7 +547,7 @@ static unsigned int isofs_get_last_session(struct super_block *sb, s32 session)
vol_desc_start=0;
ms_info.addr_format=CDROM_LBA;
if(session >= 0 && session <= 99) {
if (session > 0) {
struct cdrom_tocentry Te;
Te.cdte_track=session;
Te.cdte_format=CDROM_LBA;