| Message ID | ad940e3ced8e15ef83667ec213780b3b4a09240f.1721931241.git.josef@toxicpanda.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fanotify: add pre-content hooks | expand |
On Thu 25-07-24 14:19:41, Josef Bacik wrote: > From: Amir Goldstein <amir73il@gmail.com> > > Similar to FAN_ACCESS_PERM permission event, but it is only allowed with > class FAN_CLASS_PRE_CONTENT and only allowed on regular files are dirs. ^^ and > Unlike FAN_ACCESS_PERM, it is safe to write to the file being accessed > in the context of the event handler. > > This pre-content event is meant to be used by hierarchical storage > managers that want to fill the content of files on first read access. > > Signed-off-by: Amir Goldstein <amir73il@gmail.com> Otherwise the patch looks good. Honza > --- > fs/notify/fanotify/fanotify.c | 3 ++- > fs/notify/fanotify/fanotify_user.c | 17 ++++++++++++++--- > include/linux/fanotify.h | 14 ++++++++++---- > include/uapi/linux/fanotify.h | 2 ++ > 4 files changed, 28 insertions(+), 8 deletions(-) > > diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c > index 224bccaab4cc..7dac8e4486df 100644 > --- a/fs/notify/fanotify/fanotify.c > +++ b/fs/notify/fanotify/fanotify.c > @@ -910,8 +910,9 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask, > 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(FAN_PRE_ACCESS != FS_PRE_ACCESS); > > - BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 21); > + BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 22); > > mask = fanotify_group_event_mask(group, iter_info, &match_mask, > mask, data, data_type, dir); > diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c > index 2e2fba8a9d20..c294849e474f 100644 > --- a/fs/notify/fanotify/fanotify_user.c > +++ b/fs/notify/fanotify/fanotify_user.c > @@ -1628,6 +1628,7 @@ static int fanotify_events_supported(struct fsnotify_group *group, > unsigned int flags) > { > unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS; > + bool is_dir = d_is_dir(path->dentry); > /* Strict validation of events in non-dir inode mask with v5.17+ APIs */ > bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) || > (mask & FAN_RENAME) || > @@ -1665,9 +1666,15 @@ static int fanotify_events_supported(struct fsnotify_group *group, > * but because we always allowed it, error only when using new APIs. > */ > if (strict_dir_events && mark_type == FAN_MARK_INODE && > - !d_is_dir(path->dentry) && (mask & FANOTIFY_DIRONLY_EVENT_BITS)) > + !is_dir && (mask & FANOTIFY_DIRONLY_EVENT_BITS)) > return -ENOTDIR; > > + /* Pre-content events are only supported on regular files and dirs */ > + if (mask & FANOTIFY_PRE_CONTENT_EVENTS) { > + if (!is_dir && !d_is_reg(path->dentry)) > + return -EINVAL; > + } > + > return 0; > } > > @@ -1769,11 +1776,15 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, > goto fput_and_out; > > /* > - * Permission events require minimum priority FAN_CLASS_CONTENT. > + * Permission events are not allowed for FAN_CLASS_NOTIF. > + * Pre-content permission events are not allowed for FAN_CLASS_CONTENT. > */ > ret = -EINVAL; > if (mask & FANOTIFY_PERM_EVENTS && > - group->priority < FSNOTIFY_PRIO_CONTENT) > + group->priority == FSNOTIFY_PRIO_NORMAL) > + goto fput_and_out; > + else if (mask & FANOTIFY_PRE_CONTENT_EVENTS && > + group->priority == FSNOTIFY_PRIO_CONTENT) > goto fput_and_out; > > if (mask & FAN_FS_ERROR && > diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h > index 4f1c4f603118..5c811baf44d2 100644 > --- a/include/linux/fanotify.h > +++ b/include/linux/fanotify.h > @@ -88,6 +88,16 @@ > #define FANOTIFY_DIRENT_EVENTS (FAN_MOVE | FAN_CREATE | FAN_DELETE | \ > FAN_RENAME) > > +/* Content events can be used to inspect file content */ > +#define FANOTIFY_CONTENT_PERM_EVENTS (FAN_OPEN_PERM | FAN_OPEN_EXEC_PERM | \ > + FAN_ACCESS_PERM) > +/* Pre-content events can be used to fill file content */ > +#define FANOTIFY_PRE_CONTENT_EVENTS (FAN_PRE_ACCESS) > + > +/* Events that require a permission response from user */ > +#define FANOTIFY_PERM_EVENTS (FANOTIFY_CONTENT_PERM_EVENTS | \ > + FANOTIFY_PRE_CONTENT_EVENTS) > + > /* Events that can be reported with event->fd */ > #define FANOTIFY_FD_EVENTS (FANOTIFY_PATH_EVENTS | FANOTIFY_PERM_EVENTS) > > @@ -103,10 +113,6 @@ > FANOTIFY_INODE_EVENTS | \ > FANOTIFY_ERROR_EVENTS) > > -/* Events that require a permission response from user */ > -#define FANOTIFY_PERM_EVENTS (FAN_OPEN_PERM | FAN_ACCESS_PERM | \ > - FAN_OPEN_EXEC_PERM) > - > /* Extra flags that may be reported with event or control handling of events */ > #define FANOTIFY_EVENT_FLAGS (FAN_EVENT_ON_CHILD | FAN_ONDIR) > > diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h > index a37de58ca571..3ae43867d318 100644 > --- a/include/uapi/linux/fanotify.h > +++ b/include/uapi/linux/fanotify.h > @@ -26,6 +26,8 @@ > #define FAN_ACCESS_PERM 0x00020000 /* File accessed in perm check */ > #define FAN_OPEN_EXEC_PERM 0x00040000 /* File open/exec in perm check */ > > +#define FAN_PRE_ACCESS 0x00100000 /* Pre-content access hook */ > + > #define FAN_EVENT_ON_CHILD 0x08000000 /* Interested in child events */ > > #define FAN_RENAME 0x10000000 /* File was renamed */ > -- > 2.43.0 >
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 224bccaab4cc..7dac8e4486df 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -910,8 +910,9 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask, 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(FAN_PRE_ACCESS != FS_PRE_ACCESS); - BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 21); + BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 22); mask = fanotify_group_event_mask(group, iter_info, &match_mask, mask, data, data_type, dir); diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 2e2fba8a9d20..c294849e474f 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1628,6 +1628,7 @@ static int fanotify_events_supported(struct fsnotify_group *group, unsigned int flags) { unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS; + bool is_dir = d_is_dir(path->dentry); /* Strict validation of events in non-dir inode mask with v5.17+ APIs */ bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) || (mask & FAN_RENAME) || @@ -1665,9 +1666,15 @@ static int fanotify_events_supported(struct fsnotify_group *group, * but because we always allowed it, error only when using new APIs. */ if (strict_dir_events && mark_type == FAN_MARK_INODE && - !d_is_dir(path->dentry) && (mask & FANOTIFY_DIRONLY_EVENT_BITS)) + !is_dir && (mask & FANOTIFY_DIRONLY_EVENT_BITS)) return -ENOTDIR; + /* Pre-content events are only supported on regular files and dirs */ + if (mask & FANOTIFY_PRE_CONTENT_EVENTS) { + if (!is_dir && !d_is_reg(path->dentry)) + return -EINVAL; + } + return 0; } @@ -1769,11 +1776,15 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, goto fput_and_out; /* - * Permission events require minimum priority FAN_CLASS_CONTENT. + * Permission events are not allowed for FAN_CLASS_NOTIF. + * Pre-content permission events are not allowed for FAN_CLASS_CONTENT. */ ret = -EINVAL; if (mask & FANOTIFY_PERM_EVENTS && - group->priority < FSNOTIFY_PRIO_CONTENT) + group->priority == FSNOTIFY_PRIO_NORMAL) + goto fput_and_out; + else if (mask & FANOTIFY_PRE_CONTENT_EVENTS && + group->priority == FSNOTIFY_PRIO_CONTENT) goto fput_and_out; if (mask & FAN_FS_ERROR && diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index 4f1c4f603118..5c811baf44d2 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -88,6 +88,16 @@ #define FANOTIFY_DIRENT_EVENTS (FAN_MOVE | FAN_CREATE | FAN_DELETE | \ FAN_RENAME) +/* Content events can be used to inspect file content */ +#define FANOTIFY_CONTENT_PERM_EVENTS (FAN_OPEN_PERM | FAN_OPEN_EXEC_PERM | \ + FAN_ACCESS_PERM) +/* Pre-content events can be used to fill file content */ +#define FANOTIFY_PRE_CONTENT_EVENTS (FAN_PRE_ACCESS) + +/* Events that require a permission response from user */ +#define FANOTIFY_PERM_EVENTS (FANOTIFY_CONTENT_PERM_EVENTS | \ + FANOTIFY_PRE_CONTENT_EVENTS) + /* Events that can be reported with event->fd */ #define FANOTIFY_FD_EVENTS (FANOTIFY_PATH_EVENTS | FANOTIFY_PERM_EVENTS) @@ -103,10 +113,6 @@ FANOTIFY_INODE_EVENTS | \ FANOTIFY_ERROR_EVENTS) -/* Events that require a permission response from user */ -#define FANOTIFY_PERM_EVENTS (FAN_OPEN_PERM | FAN_ACCESS_PERM | \ - FAN_OPEN_EXEC_PERM) - /* Extra flags that may be reported with event or control handling of events */ #define FANOTIFY_EVENT_FLAGS (FAN_EVENT_ON_CHILD | FAN_ONDIR) diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h index a37de58ca571..3ae43867d318 100644 --- a/include/uapi/linux/fanotify.h +++ b/include/uapi/linux/fanotify.h @@ -26,6 +26,8 @@ #define FAN_ACCESS_PERM 0x00020000 /* File accessed in perm check */ #define FAN_OPEN_EXEC_PERM 0x00040000 /* File open/exec in perm check */ +#define FAN_PRE_ACCESS 0x00100000 /* Pre-content access hook */ + #define FAN_EVENT_ON_CHILD 0x08000000 /* Interested in child events */ #define FAN_RENAME 0x10000000 /* File was renamed */