[PATCH v7 22/28] fanotify: Report FID entry even for zero-length file_handle
From: Gabriel Krisman Bertazi <hidden>
Date: 2021-10-14 21:39:37
Also in:
linux-api, linux-fsdevel
Subsystem:
fanotify, filesystems (vfs and infrastructure), fsnotify: filesystem notification infrastructure, the rest · Maintainers:
Jan Kara, Alexander Viro, Christian Brauner, Linus Torvalds
Non-inode errors will reported with an empty file_handle. In preparation for that, allow some events to print the FID record even if there isn't any file_handle encoded Even though FILEID_ROOT is used internally, make zero-length file handles be reported as FILEID_INVALID. Signed-off-by: Gabriel Krisman Bertazi <redacted> --- fs/notify/fanotify/fanotify_user.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 5324890500fc..39cf8ba4a6ce 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c@@ -127,6 +127,16 @@ static int fanotify_fid_info_len(int fh_len, int name_len) FANOTIFY_EVENT_ALIGN); } +static bool fanotify_event_allows_empty_fh(struct fanotify_event *event) +{ + switch (event->type) { + case FANOTIFY_EVENT_TYPE_FS_ERROR: + return true; + default: + return false; + } +} + static size_t fanotify_event_len(unsigned int info_mode, struct fanotify_event *event) {
@@ -157,7 +167,7 @@ static size_t fanotify_event_len(unsigned int info_mode, if (info_mode & FAN_REPORT_PIDFD) event_len += FANOTIFY_PIDFD_INFO_HDR_LEN; - if (fh_len) + if (fh_len || fanotify_event_allows_empty_fh(event)) event_len += fanotify_fid_info_len(fh_len, dot_len); return event_len;
@@ -338,9 +348,6 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, pr_debug("%s: fh_len=%zu name_len=%zu, info_len=%zu, count=%zu\n", __func__, fh_len, name_len, info_len, count); - if (!fh_len) - return 0; - if (WARN_ON_ONCE(len < sizeof(info) || len > count)) return -EFAULT;
@@ -375,6 +382,11 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, handle.handle_type = fh->type; handle.handle_bytes = fh_len; + + /* Mangle handle_type for bad file_handle */ + if (!fh_len) + handle.handle_type = FILEID_INVALID; + if (copy_to_user(buf, &handle, sizeof(handle))) return -EFAULT;
@@ -467,7 +479,8 @@ static int copy_info_records_to_user(struct fanotify_event *event, total_bytes += ret; } - if (fanotify_event_object_fh_len(event)) { + if (fanotify_event_object_fh_len(event) || + fanotify_event_allows_empty_fh(event)) { const char *dot = NULL; int dot_len = 0;
--
2.33.0