This is a reduced version of a patch that I originally submitted a while ago. In short, the fanotify API currently does not provide any means for user space programs to receive events specifically when a file has been opened with the intent to be executed. The FAN_EXEC flag will be set within the event mask when a object has been opened with one of the open flags being __FMODE_EXEC. Linux is used as an Operating System in some products, with an environment that can be certified under the Common Criteria Operating System Protection Profile (OSPP). This is a formal threat model for a class of technology. It requires specific countermeasures to mitigate threats. It requires documentation to explain how a product implements these countermeasures. It requires proof via a test suite to demonstrate that the requirements are met, observed and checked by an independent qualified third party. The latest set of requirements for OSPP v4.2 can be found here: https://www.niap-ccevs.org/Profile/Info.cfm?PPID=424&id=424 If you look on page 58, you will see the following requirement: FPT_SRP_EXT.1 Software Restriction Policies FPT_SRP_EXT.1.1 The OS shall restrict execution to only programs which match an administrator specified [selection: file path, file digital signature, version, hash, [assignment: other characteristics] ] This patch is to help aid in meeting this requirement. Signed-off-by: Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx> --- diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 94b52157bf8d..295549479be7 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -204,6 +204,7 @@ 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); 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 ababdbfab537..e22324f4642c 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -386,7 +386,7 @@ static __init int fsnotify_init(void) { int ret; - BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23); + BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 24); ret = init_srcu_struct(&fsnotify_mark_srcu); if (ret) diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index fd1ce10553bf..aad174c81322 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -216,6 +216,9 @@ 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 b8f4182f42f1..edcdf2fd2328 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 */ @@ -62,7 +63,8 @@ #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) #define FS_MOVE (FS_MOVED_FROM | FS_MOVED_TO) @@ -75,7 +77,8 @@ 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) struct fsnotify_group; struct fsnotify_event; diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h index 74247917de04..a850670333fd 100644 --- a/include/uapi/linux/fanotify.h +++ b/include/uapi/linux/fanotify.h @@ -10,7 +10,7 @@ #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 */ @@ -69,7 +69,8 @@ #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
