Commit 8afd7215 authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

fanotify: cleanups for fanotify_mark() input validations 

Create helper fanotify_may_update_existing_mark() for checking for
conflicts between existing mark flags and fanotify_mark() flags.

Use variable mark_cmd to make the checks for mark command bits
cleaner.

Link: https://lore.kernel.org/r/20220629144210.2983229-3-amir73il@gmail.com


Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 31a371e4

fs/notify/fanotify/fanotify_user.c

+21 −9
Original line number Diff line number Diff line
@@ -1187,6 +1187,19 @@ static int fanotify_group_init_error_pool(struct fsnotify_group *group) 
					 sizeof(struct fanotify_error_event));

}



static int fanotify_may_update_existing_mark(struct fsnotify_mark *fsn_mark,

					      unsigned int fan_flags)

{

	/*

	 * Non evictable mark cannot be downgraded to evictable mark.

	 */

	if (fan_flags & FAN_MARK_EVICTABLE &&

	    !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))

		return -EEXIST;



	return 0;

}



static int fanotify_add_mark(struct fsnotify_group *group,

			     fsnotify_connp_t *connp, unsigned int obj_type,

			     __u32 mask, unsigned int fan_flags,
@@ -1208,13 +1221,11 @@ static int fanotify_add_mark(struct fsnotify_group *group, 
	}



	/*

	 * Non evictable mark cannot be downgraded to evictable mark.

	 * Check if requested mark flags conflict with an existing mark flags.

	 */

	if (fan_flags & FAN_MARK_EVICTABLE &&

	    !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)) {

		ret = -EEXIST;

	ret = fanotify_may_update_existing_mark(fsn_mark, fan_flags);

	if (ret)

		goto out;

	}



	/*

	 * Error events are pre-allocated per group, only if strictly
@@ -1557,6 +1568,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, 
	__kernel_fsid_t __fsid, *fsid = NULL;

	u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;

	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;

	unsigned int mark_cmd = flags & FANOTIFY_MARK_CMD_BITS;

	bool ignore = flags & FAN_MARK_IGNORED_MASK;

	unsigned int obj_type, fid_mode;

	u32 umask = 0;
@@ -1586,7 +1598,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, 
		return -EINVAL;

	}



	switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {

	switch (mark_cmd) {

	case FAN_MARK_ADD:

	case FAN_MARK_REMOVE:

		if (!mask)
@@ -1675,7 +1687,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, 
	if (mask & FAN_RENAME && !(fid_mode & FAN_REPORT_NAME))

		goto fput_and_out;



	if (flags & FAN_MARK_FLUSH) {

	if (mark_cmd == FAN_MARK_FLUSH) {

		ret = 0;

		if (mark_type == FAN_MARK_MOUNT)

			fsnotify_clear_vfsmount_marks_by_group(group);
@@ -1691,7 +1703,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, 
	if (ret)

		goto fput_and_out;



	if (flags & FAN_MARK_ADD) {

	if (mark_cmd == FAN_MARK_ADD) {

		ret = fanotify_events_supported(group, &path, mask, flags);

		if (ret)

			goto path_put_and_out;
@@ -1729,7 +1741,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, 
	}



	/* create/update an inode mark */

	switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {

	switch (mark_cmd) {

	case FAN_MARK_ADD:

		if (mark_type == FAN_MARK_MOUNT)

			ret = fanotify_add_vfsmount_mark(group, mnt, mask,

include/linux/fanotify.h

+5 −4
Original line number Diff line number Diff line
@@ -59,15 +59,16 @@ 
#define FANOTIFY_MARK_TYPE_BITS	(FAN_MARK_INODE | FAN_MARK_MOUNT | \

				 FAN_MARK_FILESYSTEM)



#define FANOTIFY_MARK_CMD_BITS	(FAN_MARK_ADD | FAN_MARK_REMOVE | \

				 FAN_MARK_FLUSH)



#define FANOTIFY_MARK_FLAGS	(FANOTIFY_MARK_TYPE_BITS | \

				 FAN_MARK_ADD | \

				 FAN_MARK_REMOVE | \

				 FANOTIFY_MARK_CMD_BITS | \

				 FAN_MARK_DONT_FOLLOW | \

				 FAN_MARK_ONLYDIR | \

				 FAN_MARK_IGNORED_MASK | \

				 FAN_MARK_IGNORED_SURV_MODIFY | \

				 FAN_MARK_EVICTABLE | \

				 FAN_MARK_FLUSH)

				 FAN_MARK_EVICTABLE)



/*

 * Events that can be reported with data type FSNOTIFY_EVENT_PATH.