Commit 3982534b authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

fanotify: record old and new parent and name in FAN_RENAME event 

In the special case of FAN_RENAME event, we record both the old
and new parent and name.

Link: https://lore.kernel.org/r/20211129201537.1932819-9-amir73il@gmail.com


Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 3cf984e9

fs/notify/fanotify/fanotify.c

+38 −4
Original line number Diff line number Diff line
@@ -592,21 +592,28 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *dir, 
							__kernel_fsid_t *fsid,

							const struct qstr *name,

							struct inode *child,

							struct dentry *moved,

							unsigned int *hash,

							gfp_t gfp)

{

	struct fanotify_name_event *fne;

	struct fanotify_info *info;

	struct fanotify_fh *dfh, *ffh;

	struct inode *dir2 = moved ? d_inode(moved->d_parent) : NULL;

	const struct qstr *name2 = moved ? &moved->d_name : NULL;

	unsigned int dir_fh_len = fanotify_encode_fh_len(dir);

	unsigned int dir2_fh_len = fanotify_encode_fh_len(dir2);

	unsigned int child_fh_len = fanotify_encode_fh_len(child);

	unsigned long name_len = name ? name->len : 0;

	unsigned long name2_len = name2 ? name2->len : 0;

	unsigned int len, size;



	/* Reserve terminating null byte even for empty name */

	size = sizeof(*fne) + name_len + 1;

	size = sizeof(*fne) + name_len + name2_len + 2;

	if (dir_fh_len)

		size += FANOTIFY_FH_HDR_LEN + dir_fh_len;

	if (dir2_fh_len)

		size += FANOTIFY_FH_HDR_LEN + dir2_fh_len;

	if (child_fh_len)

		size += FANOTIFY_FH_HDR_LEN + child_fh_len;

	fne = kmalloc(size, gfp);
@@ -623,6 +630,11 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *dir, 
		len = fanotify_encode_fh(dfh, dir, dir_fh_len, hash, 0);

		fanotify_info_set_dir_fh(info, len);

	}

	if (dir2_fh_len) {

		dfh = fanotify_info_dir2_fh(info);

		len = fanotify_encode_fh(dfh, dir2, dir2_fh_len, hash, 0);

		fanotify_info_set_dir2_fh(info, len);

	}

	if (child_fh_len) {

		ffh = fanotify_info_file_fh(info);

		len = fanotify_encode_fh(ffh, child, child_fh_len, hash, 0);
@@ -632,11 +644,22 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *dir, 
		fanotify_info_copy_name(info, name);

		*hash ^= full_name_hash((void *)name_len, name->name, name_len);

	}

	if (name2_len) {

		fanotify_info_copy_name2(info, name2);

		*hash ^= full_name_hash((void *)name2_len, name2->name,

					name2_len);

	}



	pr_debug("%s: size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n",

		 __func__, size, dir_fh_len, child_fh_len,

		 info->name_len, info->name_len, fanotify_info_name(info));



	if (dir2_fh_len) {

		pr_debug("%s: dir2_fh_len=%u name2_len=%u name2='%.*s'\n",

			 __func__, dir2_fh_len, info->name2_len,

			 info->name2_len, fanotify_info_name2(info));

	}



	return &fne->fae;

}
@@ -692,6 +715,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, 
	struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir);

	const struct path *path = fsnotify_data_path(data, data_type);

	struct mem_cgroup *old_memcg;

	struct dentry *moved = NULL;

	struct inode *child = NULL;

	bool name_event = false;

	unsigned int hash = 0;
@@ -727,6 +751,15 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, 
		} else if ((mask & ALL_FSNOTIFY_DIRENT_EVENTS) || !ondir) {

			name_event = true;

		}



		/*

		 * In the special case of FAN_RENAME event, we record both

		 * old and new parent+name.

		 * 'dirid' and 'file_name' are the old parent+name and

		 * 'moved' has the new parent+name.

		 */

		if (mask & FAN_RENAME)

			moved = fsnotify_data_dentry(data, data_type);

	}



	/*
@@ -748,9 +781,9 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, 
	} else if (fanotify_is_error_event(mask)) {

		event = fanotify_alloc_error_event(group, fsid, data,

						   data_type, &hash);

	} else if (name_event && (file_name || child)) {

		event = fanotify_alloc_name_event(id, fsid, file_name, child,

						  &hash, gfp);

	} else if (name_event && (file_name || moved || child)) {

		event = fanotify_alloc_name_event(dirid, fsid, file_name, child,

						  moved, &hash, gfp);

	} else if (fid_mode) {

		event = fanotify_alloc_fid_event(id, fsid, &hash, gfp);

	} else {
@@ -860,6 +893,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask, 
	BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);

	BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);

	BUILD_BUG_ON(FAN_FS_ERROR != FS_ERROR);

	BUILD_BUG_ON(FAN_RENAME != FS_RENAME);



	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 20);

include/uapi/linux/fanotify.h

+2 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 


#define FAN_EVENT_ON_CHILD	0x08000000	/* Interested in child events */



#define FAN_RENAME		0x10000000	/* File was renamed */



#define FAN_ONDIR		0x40000000	/* Event occurred against dir */



/* helper events */