Fulfill the purpose of CAP_SYS_MOUNT by adding it as a sufficient capability to mount and unmount filesystems.
Signed-off-by: Nicolas Belouin <[email protected]> --- fs/cachefiles/daemon.c | 2 +- fs/ext4/ioctl.c | 2 +- fs/namespace.c | 3 ++- fs/super.c | 14 +++++++++----- 4 files changed, 13 insertions(+), 8 deletions(-) diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 1ee54ffd3a24..fc53bdeacc8a 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -91,7 +91,7 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) _enter(""); /* only the superuser may do this */ - if (!capable(CAP_SYS_ADMIN)) + if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_MOUNT)) return -EPERM; /* the cachefiles device may only be open once at a time */ diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index afb66d4ab5cf..19d838e558e2 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -458,7 +458,7 @@ static int ext4_shutdown(struct super_block *sb, unsigned long arg) struct ext4_sb_info *sbi = EXT4_SB(sb); __u32 flags; - if (!capable(CAP_SYS_ADMIN)) + if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_MOUNT)) return -EPERM; if (get_user(flags, (__u32 __user *)arg)) diff --git a/fs/namespace.c b/fs/namespace.c index 3b601f115b6c..1eaa6a9f1631 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1661,7 +1661,8 @@ void __detach_mounts(struct dentry *dentry) */ static inline bool may_mount(void) { - return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN); + return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN) || + ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_MOUNT); } static inline bool may_mandlock(void) diff --git a/fs/super.c b/fs/super.c index 166c4ee0d0ed..1d84d8b87216 100644 --- a/fs/super.c +++ b/fs/super.c @@ -474,7 +474,7 @@ struct super_block *sget_userns(struct file_system_type *type, if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && !(type->fs_flags & FS_USERNS_MOUNT) && - !capable(CAP_SYS_ADMIN)) + !capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_MOUNT)) return ERR_PTR(-EPERM); retry: spin_lock(&sb_lock); @@ -551,7 +551,9 @@ struct super_block *sget(struct file_system_type *type, user_ns = &init_user_ns; /* Ensure the requestor has permissions over the target filesystem */ - if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN)) + if (!(flags & (SB_KERNMOUNT | SB_SUBMOUNT)) && + !ns_capable(user_ns, CAP_SYS_ADMIN) && + !ns_capable(user_ns, CAP_SYS_MOUNT)) return ERR_PTR(-EPERM); return sget_userns(type, test, set, flags, user_ns, data); @@ -1020,10 +1022,12 @@ struct dentry *mount_ns(struct file_system_type *fs_type, { struct super_block *sb; - /* Don't allow mounting unless the caller has CAP_SYS_ADMIN - * over the namespace. + /* Don't allow mounting unless the caller has CAP_SYS_ADMIN (deprecated) + * or CAP_SYS_MOUNT over the namespace. */ - if (!(flags & SB_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN)) + if (!(flags & SB_KERNMOUNT) && + !ns_capable(user_ns, CAP_SYS_ADMIN) && + !ns_capable(user_ns, CAP_SYS_MOUNT)) return ERR_PTR(-EPERM); sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags, -- 2.14.2
