diff options
Diffstat (limited to 'fs/notify/fanotify')
-rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 268 |
1 files changed, 188 insertions, 80 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 64864fb40b40..6facdf476255 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 #include <linux/fanotify.h> #include <linux/fcntl.h> +#include <linux/fdtable.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/anon_inodes.h> @@ -54,22 +55,27 @@ static int fanotify_max_queued_events __read_mostly; #include <linux/sysctl.h> +static long ft_zero = 0; +static long ft_int_max = INT_MAX; + struct ctl_table fanotify_table[] = { { .procname = "max_user_groups", .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS], - .maxlen = sizeof(int), + .maxlen = sizeof(long), .mode = 0644, - .proc_handler = proc_dointvec_minmax, - .extra1 = SYSCTL_ZERO, + .proc_handler = proc_doulongvec_minmax, + .extra1 = &ft_zero, + .extra2 = &ft_int_max, }, { .procname = "max_user_marks", .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS], - .maxlen = sizeof(int), + .maxlen = sizeof(long), .mode = 0644, - .proc_handler = proc_dointvec_minmax, - .extra1 = SYSCTL_ZERO, + .proc_handler = proc_doulongvec_minmax, + .extra1 = &ft_zero, + .extra2 = &ft_int_max, }, { .procname = "max_queued_events", @@ -104,8 +110,10 @@ struct kmem_cache *fanotify_path_event_cachep __read_mostly; struct kmem_cache *fanotify_perm_event_cachep __read_mostly; #define FANOTIFY_EVENT_ALIGN 4 -#define FANOTIFY_INFO_HDR_LEN \ +#define FANOTIFY_FID_INFO_HDR_LEN \ (sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle)) +#define FANOTIFY_PIDFD_INFO_HDR_LEN \ + sizeof(struct fanotify_event_info_pidfd) static int fanotify_fid_info_len(int fh_len, int name_len) { @@ -114,10 +122,11 @@ static int fanotify_fid_info_len(int fh_len, int name_len) if (name_len) info_len += name_len + 1; - return roundup(FANOTIFY_INFO_HDR_LEN + info_len, FANOTIFY_EVENT_ALIGN); + return roundup(FANOTIFY_FID_INFO_HDR_LEN + info_len, + FANOTIFY_EVENT_ALIGN); } -static int fanotify_event_info_len(unsigned int fid_mode, +static int fanotify_event_info_len(unsigned int info_mode, struct fanotify_event *event) { struct fanotify_info *info = fanotify_event_info(event); @@ -128,7 +137,8 @@ static int fanotify_event_info_len(unsigned int fid_mode, if (dir_fh_len) { info_len += fanotify_fid_info_len(dir_fh_len, info->name_len); - } else if ((fid_mode & FAN_REPORT_NAME) && (event->mask & FAN_ONDIR)) { + } else if ((info_mode & FAN_REPORT_NAME) && + (event->mask & FAN_ONDIR)) { /* * With group flag FAN_REPORT_NAME, if name was not recorded in * event on a directory, we will report the name ".". @@ -136,6 +146,9 @@ static int fanotify_event_info_len(unsigned int fid_mode, dot_len = 1; } + if (info_mode & FAN_REPORT_PIDFD) + info_len += FANOTIFY_PIDFD_INFO_HDR_LEN; + if (fh_len) info_len += fanotify_fid_info_len(fh_len, dot_len); @@ -171,7 +184,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group, size_t event_size = FAN_EVENT_METADATA_LEN; struct fanotify_event *event = NULL; struct fsnotify_event *fsn_event; - unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); + unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES); pr_debug("%s: group=%p count=%zd\n", __func__, group, count); @@ -181,8 +194,8 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group, goto out; event = FANOTIFY_E(fsn_event); - if (fid_mode) - event_size += fanotify_event_info_len(fid_mode, event); + if (info_mode) + event_size += fanotify_event_info_len(info_mode, event); if (event_size > count) { event = ERR_PTR(-EINVAL); @@ -303,9 +316,10 @@ static int process_access_response(struct fsnotify_group *group, return -ENOENT; } -static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, - int info_type, const char *name, size_t name_len, - char __user *buf, size_t count) +static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, + int info_type, const char *name, + size_t name_len, + char __user *buf, size_t count) { struct fanotify_event_info_fid info = { }; struct file_handle handle = { }; @@ -398,6 +412,117 @@ static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, return info_len; } +static int copy_pidfd_info_to_user(int pidfd, + char __user *buf, + size_t count) +{ + struct fanotify_event_info_pidfd info = { }; + size_t info_len = FANOTIFY_PIDFD_INFO_HDR_LEN; + + if (WARN_ON_ONCE(info_len > count)) + return -EFAULT; + + info.hdr.info_type = FAN_EVENT_INFO_TYPE_PIDFD; + info.hdr.len = info_len; + info.pidfd = pidfd; + + if (copy_to_user(buf, &info, info_len)) + return -EFAULT; + + return info_len; +} + +static int copy_info_records_to_user(struct fanotify_event *event, + struct fanotify_info *info, + unsigned int info_mode, int pidfd, + char __user *buf, size_t count) +{ + int ret, total_bytes = 0, info_type = 0; + unsigned int fid_mode = info_mode & FANOTIFY_FID_BITS; + unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD; + + /* + * Event info records order is as follows: dir fid + name, child fid. + */ + if (fanotify_event_dir_fh_len(event)) { + info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME : + FAN_EVENT_INFO_TYPE_DFID; + ret = copy_fid_info_to_user(fanotify_event_fsid(event), + fanotify_info_dir_fh(info), + info_type, + fanotify_info_name(info), + info->name_len, buf, count); + if (ret < 0) + return ret; + + buf += ret; + count -= ret; + total_bytes += ret; + } + + if (fanotify_event_object_fh_len(event)) { + const char *dot = NULL; + int dot_len = 0; + + if (fid_mode == FAN_REPORT_FID || info_type) { + /* + * With only group flag FAN_REPORT_FID only type FID is + * reported. Second info record type is always FID. + */ + info_type = FAN_EVENT_INFO_TYPE_FID; + } else if ((fid_mode & FAN_REPORT_NAME) && + (event->mask & FAN_ONDIR)) { + /* + * With group flag FAN_REPORT_NAME, if name was not + * recorded in an event on a directory, report the name + * "." with info type DFID_NAME. + */ + info_type = FAN_EVENT_INFO_TYPE_DFID_NAME; + dot = "."; + dot_len = 1; + } else if ((event->mask & ALL_FSNOTIFY_DIRENT_EVENTS) || + (event->mask & FAN_ONDIR)) { + /* + * With group flag FAN_REPORT_DIR_FID, a single info + * record has type DFID for directory entry modification + * event and for event on a directory. + */ + info_type = FAN_EVENT_INFO_TYPE_DFID; + } else { + /* + * With group flags FAN_REPORT_DIR_FID|FAN_REPORT_FID, + * a single info record has type FID for event on a + * non-directory, when there is no directory to report. + * For example, on FAN_DELETE_SELF event. + */ + info_type = FAN_EVENT_INFO_TYPE_FID; + } + + ret = copy_fid_info_to_user(fanotify_event_fsid(event), + fanotify_event_object_fh(event), + info_type, dot, dot_len, + buf, count); + if (ret < 0) + return ret; + + buf += ret; + count -= ret; + total_bytes += ret; + } + + if (pidfd_mode) { + ret = copy_pidfd_info_to_user(pidfd, buf, count); + if (ret < 0) + return ret; + + buf += ret; + count -= ret; + total_bytes += ret; + } + + return total_bytes; +} + static ssize_t copy_event_to_user(struct fsnotify_group *group, struct fanotify_event *event, char __user *buf, size_t count) @@ -405,15 +530,15 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, struct fanotify_event_metadata metadata; struct path *path = fanotify_event_path(event); struct fanotify_info *info = fanotify_event_info(event); - unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); + unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES); + unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD; struct file *f = NULL; - int ret, fd = FAN_NOFD; - int info_type = 0; + int ret, pidfd = FAN_NOPIDFD, fd = FAN_NOFD; pr_debug("%s: group=%p event=%p\n", __func__, group, event); metadata.event_len = FAN_EVENT_METADATA_LEN + - fanotify_event_info_len(fid_mode, event); + fanotify_event_info_len(info_mode, event); metadata.metadata_len = FAN_EVENT_METADATA_LEN; metadata.vers = FANOTIFY_METADATA_VERSION; metadata.reserved = 0; @@ -442,6 +567,33 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, } metadata.fd = fd; + if (pidfd_mode) { + /* + * Complain if the FAN_REPORT_PIDFD and FAN_REPORT_TID mutual + * exclusion is ever lifted. At the time of incoporating pidfd + * support within fanotify, the pidfd API only supported the + * creation of pidfds for thread-group leaders. + */ + WARN_ON_ONCE(FAN_GROUP_FLAG(group, FAN_REPORT_TID)); + + /* + * The PIDTYPE_TGID check for an event->pid is performed + * preemptively in an attempt to catch out cases where the event + * listener reads events after the event generating process has + * already terminated. Report FAN_NOPIDFD to the event listener + * in those cases, with all other pidfd creation errors being + * reported as FAN_EPIDFD. + */ + if (metadata.pid == 0 || + !pid_has_task(event->pid, PIDTYPE_TGID)) { + pidfd = FAN_NOPIDFD; + } else { + pidfd = pidfd_create(event->pid, 0); + if (pidfd < 0) + pidfd = FAN_EPIDFD; + } + } + ret = -EFAULT; /* * Sanity check copy size in case get_one_event() and @@ -462,67 +614,11 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, if (f) fd_install(fd, f); - /* Event info records order is: dir fid + name, child fid */ - if (fanotify_event_dir_fh_len(event)) { - info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME : - FAN_EVENT_INFO_TYPE_DFID; - ret = copy_info_to_user(fanotify_event_fsid(event), - fanotify_info_dir_fh(info), - info_type, fanotify_info_name(info), - info->name_len, buf, count); + if (info_mode) { + ret = copy_info_records_to_user(event, info, info_mode, pidfd, + buf, count); if (ret < 0) goto out_close_fd; - - buf += ret; - count -= ret; - } - - if (fanotify_event_object_fh_len(event)) { - const char *dot = NULL; - int dot_len = 0; - - if (fid_mode == FAN_REPORT_FID || info_type) { - /* - * With only group flag FAN_REPORT_FID only type FID is - * reported. Second info record type is always FID. - */ - info_type = FAN_EVENT_INFO_TYPE_FID; - } else if ((fid_mode & FAN_REPORT_NAME) && - (event->mask & FAN_ONDIR)) { - /* - * With group flag FAN_REPORT_NAME, if name was not - * recorded in an event on a directory, report the - * name "." with info type DFID_NAME. - */ - info_type = FAN_EVENT_INFO_TYPE_DFID_NAME; - dot = "."; - dot_len = 1; - } else if ((event->mask & ALL_FSNOTIFY_DIRENT_EVENTS) || - (event->mask & FAN_ONDIR)) { - /* - * With group flag FAN_REPORT_DIR_FID, a single info - * record has type DFID for directory entry modification - * event and for event on a directory. - */ - info_type = FAN_EVENT_INFO_TYPE_DFID; - } else { - /* - * With group flags FAN_REPORT_DIR_FID|FAN_REPORT_FID, - * a single info record has type FID for event on a - * non-directory, when there is no directory to report. - * For example, on FAN_DELETE_SELF event. - */ - info_type = FAN_EVENT_INFO_TYPE_FID; - } - - ret = copy_info_to_user(fanotify_event_fsid(event), - fanotify_event_object_fh(event), - info_type, dot, dot_len, buf, count); - if (ret < 0) - goto out_close_fd; - - buf += ret; - count -= ret; } return metadata.event_len; @@ -532,6 +628,10 @@ out_close_fd: put_unused_fd(fd); fput(f); } + + if (pidfd >= 0) + close_fd(pidfd); + return ret; } @@ -1077,6 +1177,14 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) #endif return -EINVAL; + /* + * A pidfd can only be returned for a thread-group leader; thus + * FAN_REPORT_PIDFD and FAN_REPORT_TID need to remain mutually + * exclusive. + */ + if ((flags & FAN_REPORT_PIDFD) && (flags & FAN_REPORT_TID)) + return -EINVAL; + if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS) return -EINVAL; @@ -1478,7 +1586,7 @@ static int __init fanotify_user_setup(void) FANOTIFY_DEFAULT_MAX_USER_MARKS); BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS); - BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 10); + BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 11); BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9); fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, |