Currently, the fanotify API does not provide a means for user space
programs to register and receive events specifically when a file has been
opened with the intent to be executed. Two new event flags FAN_EXEC and
FAN_EXEC_PERM have been introduced to the fanotify API along with updates
to the generic filesystem notification hooks fsnotify_open and
fsnotify_perm in order to support this capability.
Signed-off-by: Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx>
---
The proposed changes have been tested against Linus' mainline source tree
along with testing them against stable kernel releases 4.17.4, 4.17.5 and
4.17.6.
---
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index f90842efea13..4882706e2188 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -197,6 +197,8 @@ static int fanotify_handle_event(struct fsnotify_group
*group,
BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM);
BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM);
BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR);
+ BUILD_BUG_ON(FAN_EXEC != FS_EXEC);
+ BUILD_BUG_ON(FAN_EXEC_PERM != FS_EXEC_PERM);
if (!fanotify_should_send_event(iter_info, mask, data, data_type))
return 0;
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index f174397b63a0..ef5d3eca2e62 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -393,7 +393,7 @@ static __init int fsnotify_init(void)
{
int ret;
- BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
+ BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 25);
ret = init_srcu_struct(&fsnotify_mark_srcu);
if (ret)
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index bdaf22582f6e..db3ee74a7903 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -42,9 +42,12 @@ static inline int fsnotify_perm(struct file *file, int
mask)
return 0;
if (!(mask & (MAY_READ | MAY_OPEN)))
return 0;
- if (mask & MAY_OPEN)
+ if (mask & MAY_OPEN) {
fsnotify_mask = FS_OPEN_PERM;
- else if (mask & MAY_READ)
+
+ if (file->f_flags & FMODE_EXEC)
+ fsnotify_mask |= FS_EXEC_PERM;
+ } else if (mask & MAY_READ)
fsnotify_mask = FS_ACCESS_PERM;
else
BUG();
@@ -220,6 +223,9 @@ static inline void fsnotify_open(struct file *file)
if (S_ISDIR(inode->i_mode))
mask |= FS_ISDIR;
+ if (file->f_flags & FMODE_EXEC)
+ mask |= FS_EXEC;
+
fsnotify_parent(path, NULL, mask);
fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
}
diff --git a/include/linux/fsnotify_backend.h
b/include/linux/fsnotify_backend.h
index b38964a7a521..7179a82d60d4 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -38,6 +38,7 @@
#define FS_DELETE 0x00000200 /* Subfile was deleted
*/
#define FS_DELETE_SELF 0x00000400 /* Self was
deleted */
#define FS_MOVE_SELF 0x00000800 /* Self was moved */
+#define FS_EXEC 0x00001000 /* File was
executed */
#define FS_UNMOUNT 0x00002000 /* inode on umount fs
*/
#define FS_Q_OVERFLOW 0x00004000 /* Event queued
overflowed */
@@ -45,6 +46,7 @@
#define FS_OPEN_PERM 0x00010000 /* open event in an
permission hook */
#define FS_ACCESS_PERM 0x00020000 /* access event in
a permissions hook */
+#define FS_EXEC_PERM 0x00040000 /* exec event in
permission hook */
#define FS_EXCL_UNLINK 0x04000000 /* do not send
events if object is unlinked */
#define FS_ISDIR 0x40000000 /* event occurred
against dir */
@@ -62,11 +64,12 @@
#define FS_EVENTS_POSS_ON_CHILD (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
FS_CLOSE_WRITE | FS_CLOSE_NOWRITE |
FS_OPEN |\
FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE
|\
- FS_DELETE | FS_OPEN_PERM |
FS_ACCESS_PERM)
+ FS_DELETE | FS_OPEN_PERM |
FS_ACCESS_PERM |\
+ FS_EXEC | FS_EXEC_PERM)
#define FS_MOVE (FS_MOVED_FROM | FS_MOVED_TO)
-#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
+#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM |
FS_EXEC_PERM)
#define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |
\
@@ -75,7 +78,8 @@
FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED |
\
FS_OPEN_PERM | FS_ACCESS_PERM |
FS_EXCL_UNLINK | \
FS_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
- FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)
+ FS_DN_MULTISHOT | FS_EVENT_ON_CHILD |\
+ FS_EXEC | FS_EXEC_PERM)
struct fsnotify_group;
struct fsnotify_event;
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index 74247917de04..80822af0eeac 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -10,11 +10,13 @@
#define FAN_CLOSE_WRITE 0x00000008 /* Writtable file
closed */
#define FAN_CLOSE_NOWRITE 0x00000010 /* Unwrittable file
closed */
#define FAN_OPEN 0x00000020 /* File was opened */
+#define FAN_EXEC 0x00001000 /* File was executed */
#define FAN_Q_OVERFLOW 0x00004000 /* Event queued
overflowed */
#define FAN_OPEN_PERM 0x00010000 /* File open in
perm check */
#define FAN_ACCESS_PERM 0x00020000 /* File accessed
in perm check */
+#define FAN_EXEC_PERM 0x00040000 /* File executed in
perm check */
#define FAN_ONDIR 0x40000000 /* event occurred
against dir */
@@ -69,13 +71,15 @@
#define FAN_ALL_EVENTS (FAN_ACCESS |\
FAN_MODIFY |\
FAN_CLOSE |\
- FAN_OPEN)
+ FAN_OPEN |\
+ FAN_EXEC)
/*
* All events which require a permission response from userspace
*/
#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
- FAN_ACCESS_PERM)
+ FAN_ACCESS_PERM |\
+ FAN_EXEC_PERM)
#define FAN_ALL_OUTGOING_EVENTS (FAN_ALL_EVENTS |\
FAN_ALL_PERM_EVENTS |\
