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-rw-r--r--fs/notify/fanotify/fanotify.c87
-rw-r--r--fs/notify/fanotify/fanotify.h5
2 files changed, 66 insertions, 26 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 8a2bb6954e02..43a606f15370 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -14,6 +14,7 @@
#include <linux/audit.h>
#include <linux/sched/mm.h>
#include <linux/statfs.h>
+#include <linux/stringhash.h>
#include "fanotify.h"
@@ -22,12 +23,24 @@ static bool fanotify_path_equal(struct path *p1, struct path *p2)
return p1->mnt == p2->mnt && p1->dentry == p2->dentry;
}
+static unsigned int fanotify_hash_path(const struct path *path)
+{
+ return hash_ptr(path->dentry, FANOTIFY_EVENT_HASH_BITS) ^
+ hash_ptr(path->mnt, FANOTIFY_EVENT_HASH_BITS);
+}
+
static inline bool fanotify_fsid_equal(__kernel_fsid_t *fsid1,
__kernel_fsid_t *fsid2)
{
return fsid1->val[0] == fsid2->val[0] && fsid1->val[1] == fsid2->val[1];
}
+static unsigned int fanotify_hash_fsid(__kernel_fsid_t *fsid)
+{
+ return hash_32(fsid->val[0], FANOTIFY_EVENT_HASH_BITS) ^
+ hash_32(fsid->val[1], FANOTIFY_EVENT_HASH_BITS);
+}
+
static bool fanotify_fh_equal(struct fanotify_fh *fh1,
struct fanotify_fh *fh2)
{
@@ -38,6 +51,16 @@ static bool fanotify_fh_equal(struct fanotify_fh *fh1,
!memcmp(fanotify_fh_buf(fh1), fanotify_fh_buf(fh2), fh1->len);
}
+static unsigned int fanotify_hash_fh(struct fanotify_fh *fh)
+{
+ long salt = (long)fh->type | (long)fh->len << 8;
+
+ /*
+ * full_name_hash() works long by long, so it handles fh buf optimally.
+ */
+ return full_name_hash((void *)salt, fanotify_fh_buf(fh), fh->len);
+}
+
static bool fanotify_fid_event_equal(struct fanotify_fid_event *ffe1,
struct fanotify_fid_event *ffe2)
{
@@ -325,7 +348,8 @@ static int fanotify_encode_fh_len(struct inode *inode)
* Return 0 on failure to encode.
*/
static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
- unsigned int fh_len, gfp_t gfp)
+ unsigned int fh_len, unsigned int *hash,
+ gfp_t gfp)
{
int dwords, type = 0;
char *ext_buf = NULL;
@@ -368,6 +392,9 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
fh->type = type;
fh->len = fh_len;
+ /* Mix fh into event merge key */
+ *hash ^= fanotify_hash_fh(fh);
+
return FANOTIFY_FH_HDR_LEN + fh_len;
out_err:
@@ -421,6 +448,7 @@ static struct inode *fanotify_dfid_inode(u32 event_mask, const void *data,
}
static struct fanotify_event *fanotify_alloc_path_event(const struct path *path,
+ unsigned int *hash,
gfp_t gfp)
{
struct fanotify_path_event *pevent;
@@ -431,6 +459,7 @@ static struct fanotify_event *fanotify_alloc_path_event(const struct path *path,
pevent->fae.type = FANOTIFY_EVENT_TYPE_PATH;
pevent->path = *path;
+ *hash ^= fanotify_hash_path(path);
path_get(path);
return &pevent->fae;
@@ -456,6 +485,7 @@ 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,
+ unsigned int *hash,
gfp_t gfp)
{
struct fanotify_fid_event *ffe;
@@ -466,16 +496,18 @@ 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),
- gfp);
+ hash, gfp);
return &ffe->fae;
}
static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
__kernel_fsid_t *fsid,
- const struct qstr *file_name,
+ const struct qstr *name,
struct inode *child,
+ unsigned int *hash,
gfp_t gfp)
{
struct fanotify_name_event *fne;
@@ -488,24 +520,30 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
size = sizeof(*fne) + FANOTIFY_FH_HDR_LEN + dir_fh_len;
if (child_fh_len)
size += FANOTIFY_FH_HDR_LEN + child_fh_len;
- if (file_name)
- size += file_name->len + 1;
+ if (name)
+ size += name->len + 1;
fne = kmalloc(size, gfp);
if (!fne)
return NULL;
fne->fae.type = FANOTIFY_EVENT_TYPE_FID_NAME;
fne->fsid = *fsid;
+ *hash ^= fanotify_hash_fsid(fsid);
info = &fne->info;
fanotify_info_init(info);
dfh = fanotify_info_dir_fh(info);
- info->dir_fh_totlen = fanotify_encode_fh(dfh, id, dir_fh_len, 0);
+ info->dir_fh_totlen = fanotify_encode_fh(dfh, id, dir_fh_len, hash, 0);
if (child_fh_len) {
ffh = fanotify_info_file_fh(info);
- info->file_fh_totlen = fanotify_encode_fh(ffh, child, child_fh_len, 0);
+ info->file_fh_totlen = fanotify_encode_fh(ffh, child,
+ child_fh_len, hash, 0);
+ }
+ if (name) {
+ long salt = name->len;
+
+ fanotify_info_copy_name(info, name);
+ *hash ^= full_name_hash((void *)salt, name->name, name->len);
}
- if (file_name)
- fanotify_info_copy_name(info, file_name);
pr_debug("%s: ino=%lu size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n",
__func__, id->i_ino, size, dir_fh_len, child_fh_len,
@@ -530,6 +568,8 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
struct inode *child = NULL;
bool name_event = false;
unsigned int hash = 0;
+ bool ondir = mask & FAN_ONDIR;
+ struct pid *pid;
if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
/*
@@ -537,8 +577,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
* report the child fid for events reported on a non-dir child
* in addition to reporting the parent fid and maybe child name.
*/
- if ((fid_mode & FAN_REPORT_FID) &&
- id != dirid && !(mask & FAN_ONDIR))
+ if ((fid_mode & FAN_REPORT_FID) && id != dirid && !ondir)
child = id;
id = dirid;
@@ -559,8 +598,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
if (!(fid_mode & FAN_REPORT_NAME)) {
name_event = !!child;
file_name = NULL;
- } else if ((mask & ALL_FSNOTIFY_DIRENT_EVENTS) ||
- !(mask & FAN_ONDIR)) {
+ } else if ((mask & ALL_FSNOTIFY_DIRENT_EVENTS) || !ondir) {
name_event = true;
}
}
@@ -583,28 +621,25 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
event = fanotify_alloc_perm_event(path, gfp);
} else if (name_event && (file_name || child)) {
event = fanotify_alloc_name_event(id, fsid, file_name, child,
- gfp);
+ &hash, gfp);
} else if (fid_mode) {
- event = fanotify_alloc_fid_event(id, fsid, gfp);
+ event = fanotify_alloc_fid_event(id, fsid, &hash, gfp);
} else {
- event = fanotify_alloc_path_event(path, gfp);
+ event = fanotify_alloc_path_event(path, &hash, gfp);
}
if (!event)
goto out;
- /*
- * Use the victim inode instead of the watching inode as the id for
- * event queue, so event reported on parent is merged with event
- * reported on child when both directory and child watches exist.
- * Hash object id for queue merge.
- */
- hash = hash_ptr(id, FANOTIFY_EVENT_HASH_BITS);
- fanotify_init_event(event, hash, mask);
if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))
- event->pid = get_pid(task_pid(current));
+ pid = get_pid(task_pid(current));
else
- event->pid = get_pid(task_tgid(current));
+ pid = get_pid(task_tgid(current));
+
+ /* Mix event info, FAN_ONDIR flag and pid into event merge key */
+ hash ^= hash_long((unsigned long)pid | ondir, FANOTIFY_EVENT_HASH_BITS);
+ fanotify_init_event(event, hash, mask);
+ event->pid = pid;
out:
set_active_memcg(old_memcg);
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index d531f0cfa46f..9871f76cd9c2 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -115,6 +115,11 @@ static inline void fanotify_info_init(struct fanotify_info *info)
info->name_len = 0;
}
+static inline unsigned int fanotify_info_len(struct fanotify_info *info)
+{
+ return info->dir_fh_totlen + info->file_fh_totlen + info->name_len;
+}
+
static inline void fanotify_info_copy_name(struct fanotify_info *info,
const struct qstr *name)
{
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