Report mntid in an info record of type FAN_EVENT_INFO_TYPE_MNTID
with FAN_UNMOUNT event in addition to the fid info record.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify.c | 37 +++++++++++++++++++------
fs/notify/fanotify/fanotify.h | 20 +++++++++++++-
fs/notify/fanotify/fanotify_user.c | 44 +++++++++++++++++++++++++++---
include/uapi/linux/fanotify.h | 10 +++++++
4 files changed, 97 insertions(+), 14 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 384d2b2e55e7..c204259be6cc 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -17,6 +17,7 @@
#include <linux/stringhash.h>
#include "fanotify.h"
+#include "../../mount.h" /* for mnt_id */
static bool fanotify_path_equal(const struct path *p1, const struct path *p2)
{
@@ -41,6 +42,11 @@ static unsigned int fanotify_hash_fsid(__kernel_fsid_t *fsid)
hash_32(fsid->val[1], FANOTIFY_EVENT_HASH_BITS);
}
+static unsigned int fanotify_hash_mntid(int mntid)
+{
+ return hash_32(mntid, FANOTIFY_EVENT_HASH_BITS);
+}
+
static bool fanotify_fh_equal(struct fanotify_fh *fh1,
struct fanotify_fh *fh2)
{
@@ -133,6 +139,12 @@ static bool fanotify_error_event_equal(struct fanotify_error_event *fee1,
return true;
}
+/*
+ * FAN_RENAME and FAN_UNMOUNT are reported with special info record types,
+ * so we cannot merge them with other events.
+ */
+#define FANOTIFY_NO_MERGE_EVENTS (FAN_RENAME | FAN_UNMOUNT)
+
static bool fanotify_should_merge(struct fanotify_event *old,
struct fanotify_event *new)
{
@@ -153,11 +165,8 @@ static bool fanotify_should_merge(struct fanotify_event *old,
if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR))
return false;
- /*
- * FAN_RENAME event is reported with special info record types,
- * so we cannot merge it with other events.
- */
- if ((old->mask & FAN_RENAME) != (new->mask & FAN_RENAME))
+ if ((old->mask & FANOTIFY_NO_MERGE_EVENTS) ||
+ (new->mask & FANOTIFY_NO_MERGE_EVENTS))
return false;
switch (old->type) {
@@ -593,9 +602,11 @@ static struct fanotify_event *fanotify_alloc_perm_event(const struct path *path,
static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id,
__kernel_fsid_t *fsid,
+ struct mount *mnt,
unsigned int *hash,
gfp_t gfp)
{
+ unsigned int fh_len = fanotify_encode_fh_len(id);
struct fanotify_fid_event *ffe;
ffe = kmem_cache_alloc(fanotify_fid_event_cachep, gfp);
@@ -605,8 +616,14 @@ static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id,
ffe->fae.type = FANOTIFY_EVENT_TYPE_FID;
ffe->fsid = *fsid;
*hash ^= fanotify_hash_fsid(fsid);
- fanotify_encode_fh(&ffe->object_fh, id, fanotify_encode_fh_len(id),
- hash, gfp);
+ fanotify_encode_fh(&ffe->object_fh, id, fh_len, hash, gfp);
+ /* Record fid event with fsid, mntid and empty fh */
+ if (mnt && !WARN_ON_ONCE(fh_len)) {
+ ffe->mnt_id = mnt->mnt_id;
+ ffe->object_fh.flags = FANOTIFY_FH_FLAG_MNT_ID;
+ if (hash)
+ *hash ^= fanotify_hash_mntid(mnt->mnt_id);
+ }
return &ffe->fae;
}
@@ -737,6 +754,7 @@ static struct fanotify_event *fanotify_alloc_event(
fid_mode);
struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir);
const struct path *path = fsnotify_data_path(data, data_type);
+ struct mount *mnt = NULL;
struct mem_cgroup *old_memcg;
struct dentry *moved = NULL;
struct inode *child = NULL;
@@ -746,7 +764,8 @@ static struct fanotify_event *fanotify_alloc_event(
struct pid *pid;
if (mask & FAN_UNMOUNT && !WARN_ON_ONCE(!path || !fid_mode)) {
- /* Record fid event with fsid and empty fh */
+ /* Record fid event with fsid, mntid and empty fh */
+ mnt = real_mount(path->mnt);
id = NULL;
} else if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
/*
@@ -834,7 +853,7 @@ static struct fanotify_event *fanotify_alloc_event(
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);
+ event = fanotify_alloc_fid_event(id, fsid, mnt, &hash, gfp);
} else {
event = fanotify_alloc_path_event(path, &hash, gfp);
}
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index f98dcf5b7a19..3d8391a77031 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -33,6 +33,7 @@ struct fanotify_fh {
u8 type;
u8 len;
#define FANOTIFY_FH_FLAG_EXT_BUF 1
+#define FANOTIFY_FH_FLAG_MNT_ID 2
u8 flags;
u8 pad;
unsigned char buf[];
@@ -279,7 +280,10 @@ static inline void fanotify_init_event(struct fanotify_event *event,
struct { \
struct fanotify_fh (name); \
/* Space for object_fh.buf[] - access with fanotify_fh_buf() */ \
- unsigned char _inline_fh_buf[(size)]; \
+ union { \
+ unsigned char _inline_fh_buf[(size)]; \
+ int mnt_id; /* For FAN_UNMOUNT */ \
+ }; \
}
struct fanotify_fid_event {
@@ -335,6 +339,20 @@ static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event)
return NULL;
}
+static inline int fanotify_event_mntid(struct fanotify_event *event)
+{
+ struct fanotify_fh *fh = NULL;
+
+ if (event->mask & FAN_UNMOUNT &&
+ event->type == FANOTIFY_EVENT_TYPE_FID)
+ fh = &FANOTIFY_FE(event)->object_fh;
+
+ if (fh && !fh->len && fh->flags == FANOTIFY_FH_FLAG_MNT_ID)
+ return FANOTIFY_FE(event)->mnt_id;
+
+ return 0;
+}
+
static inline struct fanotify_fh *fanotify_event_object_fh(
struct fanotify_event *event)
{
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 0b3de6218c56..db3b79b8e901 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -120,7 +120,9 @@ struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
#define FANOTIFY_EVENT_ALIGN 4
#define FANOTIFY_FID_INFO_HDR_LEN \
(sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))
-#define FANOTIFY_PIDFD_INFO_HDR_LEN \
+#define FANOTIFY_MNTID_INFO_LEN \
+ sizeof(struct fanotify_event_info_mntid)
+#define FANOTIFY_PIDFD_INFO_LEN \
sizeof(struct fanotify_event_info_pidfd)
#define FANOTIFY_ERROR_INFO_LEN \
(sizeof(struct fanotify_event_info_error))
@@ -178,8 +180,11 @@ static size_t fanotify_event_len(unsigned int info_mode,
dot_len = 1;
}
+ if (fanotify_event_mntid(event))
+ event_len += FANOTIFY_MNTID_INFO_LEN;
+
if (info_mode & FAN_REPORT_PIDFD)
- event_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
+ event_len += FANOTIFY_PIDFD_INFO_LEN;
if (fanotify_event_has_object_fh(event)) {
fh_len = fanotify_event_object_fh_len(event);
@@ -515,7 +520,7 @@ static int copy_pidfd_info_to_user(int pidfd,
size_t count)
{
struct fanotify_event_info_pidfd info = { };
- size_t info_len = FANOTIFY_PIDFD_INFO_HDR_LEN;
+ size_t info_len = FANOTIFY_PIDFD_INFO_LEN;
if (WARN_ON_ONCE(info_len > count))
return -EFAULT;
@@ -530,6 +535,26 @@ static int copy_pidfd_info_to_user(int pidfd,
return info_len;
}
+static int copy_mntid_info_to_user(int mntid,
+ char __user *buf,
+ size_t count)
+{
+ struct fanotify_event_info_mntid info = { };
+ size_t info_len = FANOTIFY_MNTID_INFO_LEN;
+
+ if (WARN_ON_ONCE(info_len > count))
+ return -EFAULT;
+
+ info.hdr.info_type = FAN_EVENT_INFO_TYPE_MNTID;
+ info.hdr.len = info_len;
+ info.mnt_id = mntid;
+
+ if (copy_to_user(buf, &info, info_len))
+ return -EFAULT;
+
+ return info_len;
+}
+
static int copy_info_records_to_user(struct fanotify_event *event,
struct fanotify_info *info,
unsigned int info_mode, int pidfd,
@@ -538,6 +563,7 @@ static int copy_info_records_to_user(struct fanotify_event *event,
int ret, total_bytes = 0, info_type = 0;
unsigned int fid_mode = info_mode & FANOTIFY_FID_BITS;
unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
+ int mntid = fanotify_event_mntid(event);
/*
* Event info records order is as follows:
@@ -632,6 +658,16 @@ static int copy_info_records_to_user(struct fanotify_event *event,
total_bytes += ret;
}
+ if (mntid) {
+ ret = copy_mntid_info_to_user(mntid, buf, count);
+ if (ret < 0)
+ return ret;
+
+ buf += ret;
+ count -= ret;
+ total_bytes += ret;
+ }
+
if (pidfd_mode) {
ret = copy_pidfd_info_to_user(pidfd, buf, count);
if (ret < 0)
@@ -1770,7 +1806,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
* inotify sends unsoliciled IN_UNMOUNT per marked inode on sb shutdown.
* FAN_UNMOUNT event is about unmount of a mount, not about sb shutdown,
* so allow setting it only in mount mark mask.
- * FAN_UNMOUNT requires FAN_REPORT_FID to report fsid with empty fh.
+ * FAN_UNMOUNT requires FAN_REPORT_FID to report fsid and mntid.
*/
if (mask & FAN_UNMOUNT &&
(!(fid_mode & FAN_REPORT_FID) || mark_type != FAN_MARK_MOUNT))
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index 70f2d43e8ba4..886efbd877ba 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -144,6 +144,7 @@ struct fanotify_event_metadata {
#define FAN_EVENT_INFO_TYPE_DFID 3
#define FAN_EVENT_INFO_TYPE_PIDFD 4
#define FAN_EVENT_INFO_TYPE_ERROR 5
+#define FAN_EVENT_INFO_TYPE_MNTID 6
/* Special info types for FAN_RENAME */
#define FAN_EVENT_INFO_TYPE_OLD_DFID_NAME 10
@@ -184,6 +185,15 @@ struct fanotify_fhandle {
__u64 fh_ino;
};
+/*
+ * This structure is used for info records of type FAN_EVENT_INFO_TYPE_MNTID.
+ */
+struct fanotify_event_info_mntid {
+ struct fanotify_event_info_header hdr;
+ /* matches mount_id from name_to_handle_at(2) */
+ __s32 mnt_id;
+};
+
/*
* This structure is used for info records of type FAN_EVENT_INFO_TYPE_PIDFD.
* It holds a pidfd for the pid that was responsible for generating an event.
--
2.34.1
