Similar to inotify's IN_MARK_CREATE, adding an fanotify mark with flag
FAN_MARK_CREATE will fail with error EEXIST if an fanotify mark already
exists on the object.
Unlike inotify's IN_MARK_CREATE, FAN_MARK_CREATE has to supplied in
combination with FAN_MARK_ADD (FAN_MARK_ADD is like inotify_add_watch()
and the behavior of IN_MARK_ADD is the default for fanotify_mark()).
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify_user.c | 13 ++++++++++---
include/linux/fanotify.h | 8 +++++---
include/uapi/linux/fanotify.h | 1 +
3 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 9b32b76a9c30..99c5ced6abd8 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1185,6 +1185,9 @@ static int fanotify_add_mark(struct fsnotify_group *group,
mutex_unlock(&group->mark_mutex);
return PTR_ERR(fsn_mark);
}
+ } else if (flags & FAN_MARK_CREATE) {
+ ret = -EEXIST;
+ goto out;
}
/*
@@ -1510,6 +1513,7 @@ 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 ignored = flags & FAN_MARK_IGNORED_MASK;
unsigned int obj_type, fid_mode;
u32 umask = 0;
@@ -1539,7 +1543,10 @@ 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)) {
+ if (flags & FAN_MARK_CREATE && mark_cmd != FAN_MARK_ADD)
+ return -EINVAL;
+
+ switch (mark_cmd) {
case FAN_MARK_ADD:
case FAN_MARK_REMOVE:
if (!mask)
@@ -1671,7 +1678,7 @@ 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,
@@ -1749,7 +1756,7 @@ static int __init fanotify_user_setup(void)
BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 12);
- BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);
+ BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 10);
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
SLAB_PANIC|SLAB_ACCOUNT);
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 419cadcd7ff5..780f4b17d4c9 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -59,14 +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_FLUSH)
+ FAN_MARK_CREATE)
/*
* Events that can be reported with data type FSNOTIFY_EVENT_PATH.
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index e8ac38cc2fd6..c41feac21fe9 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -82,6 +82,7 @@
#define FAN_MARK_IGNORED_SURV_MODIFY 0x00000040
#define FAN_MARK_FLUSH 0x00000080
/* FAN_MARK_FILESYSTEM is 0x00000100 */
+#define FAN_MARK_CREATE 0x00000200
/* These are NOT bitwise flags. Both bits can be used togther. */
#define FAN_MARK_INODE 0x00000000
--
2.25.1
