From 34363c057b368114d8b93376ec6b65ef5f36a55b Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 18 Jul 2017 12:27:56 +0200 Subject: [PATCH] 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 Signed-off-by: Jan Kara --- fs/isofs/inode.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c index 8cf898a59730..217a5e7815da 100644 --- a/fs/isofs/inode.c +++ b/fs/isofs/inode.c @@ -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; -- 2.30.2