From 58985a9d2d03e977db93bf574a16162766a318fe Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Valdis=20Kl=C4=93tnieks?= Date: Fri, 30 Aug 2019 12:42:39 -0400 Subject: [PATCH] drivers/staging/exfat - by default, prohibit mount of fat/vfat Concerns have been raised about the exfat driver accidentally mounting fat/vfat file systems. Add an extra configure option to help prevent that. Signed-off-by: Valdis Kletnieks Link: https://lore.kernel.org/r/245727.1567183359@turing-police Signed-off-by: Greg Kroah-Hartman --- drivers/staging/exfat/Kconfig | 8 ++++++++ drivers/staging/exfat/exfat_super.c | 6 ++++++ 2 files changed, 14 insertions(+) diff --git a/drivers/staging/exfat/Kconfig b/drivers/staging/exfat/Kconfig index 78b32aa2ca19..f52129c67f97 100644 --- a/drivers/staging/exfat/Kconfig +++ b/drivers/staging/exfat/Kconfig @@ -4,6 +4,14 @@ config EXFAT_FS help This adds support for the exFAT file system. +config EXFAT_DONT_MOUNT_VFAT + bool "Prohibit mounting of fat/vfat filesysems by exFAT" + default y + help + By default, the exFAT driver will only mount exFAT filesystems, and refuse + to mount fat/vfat filesystems. Set this to 'n' to allow the exFAT driver + to mount these filesystems. + config EXFAT_DISCARD bool "enable discard support" depends on EXFAT_FS diff --git a/drivers/staging/exfat/exfat_super.c b/drivers/staging/exfat/exfat_super.c index 5b5c2ca8c9aa..d9787635a373 100644 --- a/drivers/staging/exfat/exfat_super.c +++ b/drivers/staging/exfat/exfat_super.c @@ -486,10 +486,16 @@ static int ffsMountVol(struct super_block *sb) break; if (i < 53) { +#ifdef CONFIG_EXFAT_DONT_MOUNT_VFAT + ret = -EINVAL; + printk(KERN_INFO "EXFAT: Attempted to mount VFAT filesystem\n"); + goto out; +#else if (GET16(p_pbr->bpb + 11)) /* num_fat_sectors */ ret = fat16_mount(sb, p_pbr); else ret = fat32_mount(sb, p_pbr); +#endif } else { ret = exfat_mount(sb, p_pbr); }