diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index df08f13052ff4b53f19f28803ea9baedfb64c718..8bb1a01fef2a1e6a011b5d3b5c03ad24ade2825c 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -798,7 +798,7 @@ static int ptmx_open(struct inode *inode, struct file *filp) nonseekable_open(inode, filp); /* We refuse fsnotify events on ptmx, since it's a shared resource */ - filp->f_mode |= FMODE_NONOTIFY; + file_set_fsnotify_mode(filp, FMODE_NONOTIFY); retval = tty_alloc_file(filp); if (retval) diff --git a/fs/file_table.c b/fs/file_table.c index d4632ef96a1c18d75009c21d5df5230f7b6ad164..7b06bbe71494c81a176d9fcc896642dc27ddc9bc 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -202,6 +202,11 @@ static int init_file(struct file *f, int flags, const struct cred *cred) f->f_mode = OPEN_FMODE(flags); /* f->f_version: 0 */ + /* + * Disable permission and pre-content events for all files by default. + * They may be enabled later by fsnotify_open_perm_and_set_mode(). + */ + file_set_fsnotify_mode(f, FMODE_NONOTIFY_PERM); return 0; } @@ -384,7 +389,13 @@ struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt, if (IS_ERR(file)) { ihold(inode); path_put(&path); + return file; } + /* + * Disable all fsnotify events for pseudo files by default. + * They may be enabled by caller with file_set_fsnotify_mode(). + */ + file_set_fsnotify_mode(file, FMODE_NONOTIFY); return file; } EXPORT_SYMBOL(alloc_file_pseudo); diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 6621b9163e4ef63f0867bd8c17718da0cb55d994..b7a8d0b91a7d1e0025d8a78f37befee4affb68ca 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -192,8 +192,8 @@ static bool fsnotify_event_needs_parent(struct inode *inode, __u32 mnt_mask, } /* Are there any inode/mount/sb objects that watch for these events? */ -static inline bool fsnotify_object_watched(struct inode *inode, __u32 mnt_mask, - __u32 mask) +static inline __u32 fsnotify_object_watched(struct inode *inode, __u32 mnt_mask, + __u32 mask) { __u32 marks_mask = inode->i_fsnotify_mask | mnt_mask | inode->i_sb->s_fsnotify_mask; @@ -647,20 +647,20 @@ EXPORT_SYMBOL_GPL(fsnotify); #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS /* - * At open time we check fsnotify_sb_has_priority_watchers() and set the - * FMODE_NONOTIFY_ mode bits accordignly. + * At open time we check fsnotify_sb_has_priority_watchers(), call the open perm + * hook and set the FMODE_NONOTIFY_ mode bits accordignly. * Later, fsnotify permission hooks do not check if there are permission event * watches, but that there were permission event watches at open time. */ -void file_set_fsnotify_mode(struct file *file) +int fsnotify_open_perm_and_set_mode(struct file *file) { struct dentry *dentry = file->f_path.dentry, *parent; struct super_block *sb = dentry->d_sb; - __u32 mnt_mask, p_mask; + __u32 mnt_mask, p_mask = 0; /* Is it a file opened by fanotify? */ if (FMODE_FSNOTIFY_NONE(file->f_mode)) - return; + return 0; /* * Permission events is a super set of pre-content events, so if there @@ -669,40 +669,65 @@ void file_set_fsnotify_mode(struct file *file) */ if (likely(!fsnotify_sb_has_priority_watchers(sb, FSNOTIFY_PRIO_CONTENT))) { - file->f_mode |= FMODE_NONOTIFY_PERM; - return; + file_set_fsnotify_mode(file, FMODE_NONOTIFY_PERM); + return 0; + } + + /* + * OK, there are some permission event watchers. Check if anybody is + * watching for permission events on *this* file. + */ + mnt_mask = READ_ONCE(real_mount(file->f_path.mnt)->mnt_fsnotify_mask); + p_mask = fsnotify_object_watched(d_inode(dentry), mnt_mask, + ALL_FSNOTIFY_PERM_EVENTS); + if (dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED) { + parent = dget_parent(dentry); + p_mask |= fsnotify_inode_watches_children(d_inode(parent)); + dput(parent); + } + + /* + * Legacy FAN_ACCESS_PERM events have very high performance overhead, + * so unlikely to be used in the wild. If they are used there will be + * no optimizations at all. + */ + if (unlikely(p_mask & FS_ACCESS_PERM)) { + /* Enable all permission and pre-content events */ + file_set_fsnotify_mode(file, 0); + goto open_perm; } /* - * If there are permission event watchers but no pre-content event + * Pre-content events are only supported on regular files. + * If there are pre-content event watchers and no permission access * watchers, set FMODE_NONOTIFY | FMODE_NONOTIFY_PERM to indicate that. + * That is the common case with HSM service. */ - if ((!d_is_dir(dentry) && !d_is_reg(dentry)) || - likely(!fsnotify_sb_has_priority_watchers(sb, - FSNOTIFY_PRIO_PRE_CONTENT))) { - file->f_mode |= FMODE_NONOTIFY | FMODE_NONOTIFY_PERM; - return; + if (d_is_reg(dentry) && (p_mask & FSNOTIFY_PRE_CONTENT_EVENTS)) { + file_set_fsnotify_mode(file, FMODE_NONOTIFY | + FMODE_NONOTIFY_PERM); + goto open_perm; } + /* Nobody watching permission and pre-content events on this file */ + file_set_fsnotify_mode(file, FMODE_NONOTIFY_PERM); + +open_perm: /* - * OK, there are some pre-content watchers. Check if anybody is - * watching for pre-content events on *this* file. + * Send open perm events depending on object masks and regardless of + * FMODE_NONOTIFY_PERM. */ - mnt_mask = READ_ONCE(real_mount(file->f_path.mnt)->mnt_fsnotify_mask); - if (unlikely(fsnotify_object_watched(d_inode(dentry), mnt_mask, - FSNOTIFY_PRE_CONTENT_EVENTS))) - return; + if (file->f_flags & __FMODE_EXEC && p_mask & FS_OPEN_EXEC_PERM) { + int ret = fsnotify_path(&file->f_path, FS_OPEN_EXEC_PERM); - /* Is parent watching for pre-content events on this file? */ - if (dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED) { - parent = dget_parent(dentry); - p_mask = fsnotify_inode_watches_children(d_inode(parent)); - dput(parent); - if (p_mask & FSNOTIFY_PRE_CONTENT_EVENTS) - return; + if (ret) + return ret; } - /* Nobody watching for pre-content events from this file */ - file->f_mode |= FMODE_NONOTIFY | FMODE_NONOTIFY_PERM; + + if (p_mask & FS_OPEN_PERM) + return fsnotify_path(&file->f_path, FS_OPEN_PERM); + + return 0; } #endif diff --git a/fs/open.c b/fs/open.c index 36d8034c69c297924e13fe0689793f63cabc295a..08cc707f430547ef5c97329548e2a223bb313873 100644 --- a/fs/open.c +++ b/fs/open.c @@ -923,7 +923,8 @@ static int do_dentry_open(struct file *f, f->f_sb_err = file_sample_sb_err(f); if (unlikely(f->f_flags & O_PATH)) { - f->f_mode = FMODE_PATH | FMODE_OPENED | FMODE_NONOTIFY; + f->f_mode = FMODE_PATH | FMODE_OPENED; + file_set_fsnotify_mode(f, FMODE_NONOTIFY); f->f_op = &empty_fops; return 0; } @@ -952,12 +953,12 @@ static int do_dentry_open(struct file *f, goto cleanup_all; /* - * Set FMODE_NONOTIFY_* bits according to existing permission watches. - * If FMODE_NONOTIFY was already set for an fanotify fd, this doesn't - * change anything. + * Call fsnotify open permission hook and set FMODE_NONOTIFY_* bits + * according to existing permission watches. + * If FMODE_NONOTIFY mode was already set for an fanotify fd or for a + * pseudo file, this call will not change the mode. */ - file_set_fsnotify_mode(f); - error = fsnotify_open_perm(f); + error = fsnotify_open_perm_and_set_mode(f); if (error) goto cleanup_all; @@ -1142,7 +1143,7 @@ struct file *dentry_open_nonotify(const struct path *path, int flags, if (!IS_ERR(f)) { int error; - f->f_mode |= FMODE_NONOTIFY; + file_set_fsnotify_mode(f, FMODE_NONOTIFY); error = vfs_open(path, f); if (error) { fput(f); diff --git a/fs/pipe.c b/fs/pipe.c index ba4376341ddd2f392fb38c3cc894e549e3b7f154..d4ccef4063bae05a8077a7d00587d35d59c59231 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -954,6 +954,12 @@ int create_pipe_files(struct file **res, int flags) res[1] = f; stream_open(inode, res[0]); stream_open(inode, res[1]); + /* + * Disable permission and pre-content events, but enable legacy + * inotify events for legacy users. + */ + file_set_fsnotify_mode(res[0], FMODE_NONOTIFY_PERM); + file_set_fsnotify_mode(res[1], FMODE_NONOTIFY_PERM); return 0; } diff --git a/include/linux/fs.h b/include/linux/fs.h index 2e3c5aa7927778084f54564216b625acf03d1151..6a12417faf9652dbdfed05da6e710fb27f65ad36 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -192,12 +192,12 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, /* * The two FMODE_NONOTIFY* define which fsnotify events should not be generated - * for a file. These are the possible values of (f->f_mode & - * FMODE_FSNOTIFY_MASK) and their meaning: + * for an open file. These are the possible values of + * (f->f_mode & FMODE_FSNOTIFY_MASK) and their meaning: * * FMODE_NONOTIFY - suppress all (incl. non-permission) events. * FMODE_NONOTIFY_PERM - suppress permission (incl. pre-content) events. - * FMODE_NONOTIFY | FMODE_NONOTIFY_PERM - suppress only pre-content events. + * FMODE_NONOTIFY | FMODE_NONOTIFY_PERM - suppress only FAN_ACCESS_PERM. */ #define FMODE_FSNOTIFY_MASK \ (FMODE_NONOTIFY | FMODE_NONOTIFY_PERM) @@ -205,17 +205,16 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define FMODE_FSNOTIFY_NONE(mode) \ ((mode & FMODE_FSNOTIFY_MASK) == FMODE_NONOTIFY) #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS -#define FMODE_FSNOTIFY_PERM(mode) \ +#define FMODE_FSNOTIFY_HSM(mode) \ ((mode & FMODE_FSNOTIFY_MASK) == 0 || \ (mode & FMODE_FSNOTIFY_MASK) == (FMODE_NONOTIFY | FMODE_NONOTIFY_PERM)) -#define FMODE_FSNOTIFY_HSM(mode) \ +#define FMODE_FSNOTIFY_ACCESS_PERM(mode) \ ((mode & FMODE_FSNOTIFY_MASK) == 0) #else -#define FMODE_FSNOTIFY_PERM(mode) 0 +#define FMODE_FSNOTIFY_ACCESS_PERM(mode) 0 #define FMODE_FSNOTIFY_HSM(mode) 0 #endif - /* * Attribute flags. These should be or-ed together to figure out what * has been changed! @@ -3069,6 +3068,12 @@ static inline void exe_file_allow_write_access(struct file *exe_file) allow_write_access(exe_file); } +static inline void file_set_fsnotify_mode(struct file *file, fmode_t mode) +{ + file->f_mode &= ~FMODE_FSNOTIFY_MASK; + file->f_mode |= mode; +} + static inline bool inode_is_open_for_write(const struct inode *inode) { return atomic_read(&inode->i_writecount) > 0; diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index ae4d57316499bf5250db632e5db395128b671ae6..6e8084f8ef2763e0794a6adc798a35ee49810f2b 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -129,7 +129,7 @@ static inline int fsnotify_file(struct file *file, __u32 mask) #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS -void file_set_fsnotify_mode(struct file *file); +int fsnotify_open_perm_and_set_mode(struct file *file); /* * fsnotify_file_area_perm - permission hook before access to file range @@ -147,9 +147,6 @@ static inline int fsnotify_file_area_perm(struct file *file, int perm_mask, if (!(perm_mask & (MAY_READ | MAY_WRITE | MAY_ACCESS))) return 0; - if (likely(!FMODE_FSNOTIFY_PERM(file->f_mode))) - return 0; - /* * read()/write() and other types of access generate pre-content events. */ @@ -160,7 +157,8 @@ static inline int fsnotify_file_area_perm(struct file *file, int perm_mask, return ret; } - if (!(perm_mask & MAY_READ)) + if (!(perm_mask & MAY_READ) || + likely(!FMODE_FSNOTIFY_ACCESS_PERM(file->f_mode))) return 0; /* @@ -208,28 +206,10 @@ static inline int fsnotify_file_perm(struct file *file, int perm_mask) return fsnotify_file_area_perm(file, perm_mask, NULL, 0); } -/* - * fsnotify_open_perm - permission hook before file open - */ -static inline int fsnotify_open_perm(struct file *file) -{ - int ret; - - if (likely(!FMODE_FSNOTIFY_PERM(file->f_mode))) - return 0; - - if (file->f_flags & __FMODE_EXEC) { - ret = fsnotify_path(&file->f_path, FS_OPEN_EXEC_PERM); - if (ret) - return ret; - } - - return fsnotify_path(&file->f_path, FS_OPEN_PERM); -} - #else -static inline void file_set_fsnotify_mode(struct file *file) +static inline int fsnotify_open_perm_and_set_mode(struct file *file) { + return 0; } static inline int fsnotify_file_area_perm(struct file *file, int perm_mask, @@ -253,11 +233,6 @@ static inline int fsnotify_file_perm(struct file *file, int perm_mask) { return 0; } - -static inline int fsnotify_open_perm(struct file *file) -{ - return 0; -} #endif /* diff --git a/net/socket.c b/net/socket.c index d977ac010b9ef6fc6150c3799068f73414fa4d25..0add654a50c20b4f78365c207f52869b721394e8 100644 --- a/net/socket.c +++ b/net/socket.c @@ -478,6 +478,11 @@ struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname) sock->file = file; file->private_data = sock; stream_open(SOCK_INODE(sock), file); + /* + * Disable permission and pre-content events, but enable legacy + * inotify events for legacy users. + */ + file_set_fsnotify_mode(file, FMODE_NONOTIFY_PERM); return file; } EXPORT_SYMBOL(sock_alloc_file);