Commit 936d6a38 authored by Gabriel Krisman Bertazi's avatar Gabriel Krisman Bertazi Committed by Jan Kara
Browse files

fanotify: Report fid info for file related file system errors 

Plumb the pieces to add a FID report to error records.  Since all error
event memory must be pre-allocated, we pre-allocate the maximum file
handle size possible, such that it should always fit.

For errors that don't expose a file handle, report it with an invalid
FID. Internally we use zero-length FILEID_ROOT file handle for passing
the information (which we report as zero-length FILEID_INVALID file
handle to userspace) so we update the handle reporting code to deal with
this case correctly.

Link: https://lore.kernel.org/r/20211025192746.66445-27-krisman@collabora.com
Link: https://lore.kernel.org/r/20211025192746.66445-25-krisman@collabora.com


Signed-off-by: default avatarGabriel Krisman Bertazi <krisman@collabora.com>
Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
[Folded two patches into 2 to make series bisectable]
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 572c28f2

fs/notify/fanotify/fanotify.c

+11 −0
Original line number Diff line number Diff line
@@ -609,7 +609,9 @@ static struct fanotify_event *fanotify_alloc_error_event( 
{

	struct fs_error_report *report =

			fsnotify_data_error_report(data, data_type);

	struct inode *inode;

	struct fanotify_error_event *fee;

	int fh_len;



	if (WARN_ON_ONCE(!report))

		return NULL;
@@ -622,6 +624,15 @@ static struct fanotify_event *fanotify_alloc_error_event( 
	fee->err_count = 1;

	fee->fsid = *fsid;



	inode = report->inode;

	fh_len = fanotify_encode_fh_len(inode);



	/* Bad fh_len. Fallback to using an invalid fh. Should never happen. */

	if (!fh_len && inode)

		inode = NULL;



	fanotify_encode_fh(&fee->object_fh, inode, fh_len, NULL, 0);



	*hash ^= fanotify_hash_fsid(fsid);



	return &fee->fae;

fs/notify/fanotify/fanotify.h

+9 −0
Original line number Diff line number Diff line
@@ -208,6 +208,8 @@ struct fanotify_error_event { 
	u32 err_count; /* Suppressed errors count */



	__kernel_fsid_t fsid; /* FSID this error refers to. */



	FANOTIFY_INLINE_FH(object_fh, MAX_HANDLE_SZ);

};



static inline struct fanotify_error_event *
@@ -222,6 +224,8 @@ static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event) 
		return &FANOTIFY_FE(event)->fsid;

	else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)

		return &FANOTIFY_NE(event)->fsid;

	else if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR)

		return &FANOTIFY_EE(event)->fsid;

	else

		return NULL;

}
@@ -233,6 +237,8 @@ static inline struct fanotify_fh *fanotify_event_object_fh( 
		return &FANOTIFY_FE(event)->object_fh;

	else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)

		return fanotify_info_file_fh(&FANOTIFY_NE(event)->info);

	else if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR)

		return &FANOTIFY_EE(event)->object_fh;

	else

		return NULL;

}
@@ -266,6 +272,9 @@ static inline int fanotify_event_dir_fh_len(struct fanotify_event *event) 


static inline bool fanotify_event_has_object_fh(struct fanotify_event *event)

{

	/* For error events, even zeroed fh are reported. */

	if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR)

		return true;

	return fanotify_event_object_fh_len(event) > 0;

}

fs/notify/fanotify/fanotify_user.c

+5 −3
Original line number Diff line number Diff line
@@ -339,9 +339,6 @@ 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;
@@ -376,6 +373,11 @@ 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;