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

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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: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Amir Goldstein 2021-11-29 22:15:34 +02:00 committed by Jan Kara
parent 3cf984e950
commit 3982534ba5
2 changed files with 40 additions and 4 deletions
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42
fs/notify/fanotify/fanotify.c
View File

@ -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);

2
include/uapi/linux/fanotify.h
View File

@ -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 */