diff options
Diffstat (limited to 'fs/proc/fd.c')
-rw-r--r-- | fs/proc/fd.c | 94 |
1 files changed, 56 insertions, 38 deletions
diff --git a/fs/proc/fd.c b/fs/proc/fd.c index 81882a13212d..913bef0d2a36 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -6,6 +6,7 @@ #include <linux/fdtable.h> #include <linux/namei.h> #include <linux/pid.h> +#include <linux/ptrace.h> #include <linux/security.h> #include <linux/file.h> #include <linux/seq_file.h> @@ -28,14 +29,13 @@ static int seq_show(struct seq_file *m, void *v) if (!task) return -ENOENT; - files = get_files_struct(task); - put_task_struct(task); - + task_lock(task); + files = task->files; if (files) { unsigned int fd = proc_fd(m->private); spin_lock(&files->file_lock); - file = fcheck_files(files, fd); + file = files_lookup_fd_locked(files, fd); if (file) { struct fdtable *fdt = files_fdtable(files); @@ -47,16 +47,19 @@ static int seq_show(struct seq_file *m, void *v) ret = 0; } spin_unlock(&files->file_lock); - put_files_struct(files); } + task_unlock(task); + put_task_struct(task); if (ret) return ret; - seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n", + seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n", (long long)file->f_pos, f_flags, - real_mount(file->f_path.mnt)->mnt_id); + real_mount(file->f_path.mnt)->mnt_id, + file_inode(file)->i_ino); + /* show_fd_locks() never deferences files so a stale value is safe */ show_fd_locks(m, file, files); if (seq_has_overflowed(m)) goto out; @@ -69,8 +72,30 @@ out: return 0; } +static int proc_fdinfo_access_allowed(struct inode *inode) +{ + bool allowed = false; + struct task_struct *task = get_proc_task(inode); + + if (!task) + return -ESRCH; + + allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS); + put_task_struct(task); + + if (!allowed) + return -EACCES; + + return 0; +} + static int seq_fdinfo_open(struct inode *inode, struct file *file) { + int ret = proc_fdinfo_access_allowed(inode); + + if (ret) + return ret; + return single_open(file, seq_show, inode); } @@ -83,18 +108,13 @@ static const struct file_operations proc_fdinfo_file_operations = { static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode) { - struct files_struct *files = get_files_struct(task); struct file *file; - if (!files) - return false; - rcu_read_lock(); - file = fcheck_files(files, fd); + file = task_lookup_fd_rcu(task, fd); if (file) *mode = file->f_mode; rcu_read_unlock(); - put_files_struct(files); return !!file; } @@ -146,29 +166,22 @@ static const struct dentry_operations tid_fd_dentry_operations = { static int proc_fd_link(struct dentry *dentry, struct path *path) { - struct files_struct *files = NULL; struct task_struct *task; int ret = -ENOENT; task = get_proc_task(d_inode(dentry)); if (task) { - files = get_files_struct(task); - put_task_struct(task); - } - - if (files) { unsigned int fd = proc_fd(d_inode(dentry)); struct file *fd_file; - spin_lock(&files->file_lock); - fd_file = fcheck_files(files, fd); + fd_file = fget_task(task, fd); if (fd_file) { *path = fd_file->f_path; path_get(&fd_file->f_path); ret = 0; + fput(fd_file); } - spin_unlock(&files->file_lock); - put_files_struct(files); + put_task_struct(task); } return ret; @@ -229,7 +242,6 @@ static int proc_readfd_common(struct file *file, struct dir_context *ctx, instantiate_t instantiate) { struct task_struct *p = get_proc_task(file_inode(file)); - struct files_struct *files; unsigned int fd; if (!p) @@ -237,22 +249,18 @@ static int proc_readfd_common(struct file *file, struct dir_context *ctx, if (!dir_emit_dots(file, ctx)) goto out; - files = get_files_struct(p); - if (!files) - goto out; rcu_read_lock(); - for (fd = ctx->pos - 2; - fd < files_fdtable(files)->max_fds; - fd++, ctx->pos++) { + for (fd = ctx->pos - 2;; fd++) { struct file *f; struct fd_data data; char name[10 + 1]; unsigned int len; - f = fcheck_files(files, fd); + f = task_lookup_next_fd_rcu(p, &fd); + ctx->pos = fd + 2LL; if (!f) - continue; + break; data.mode = f->f_mode; rcu_read_unlock(); data.fd = fd; @@ -261,13 +269,11 @@ static int proc_readfd_common(struct file *file, struct dir_context *ctx, if (!proc_fill_cache(file, ctx, name, len, instantiate, p, &data)) - goto out_fd_loop; + goto out; cond_resched(); rcu_read_lock(); } rcu_read_unlock(); -out_fd_loop: - put_files_struct(files); out: put_task_struct(p); return 0; @@ -294,12 +300,13 @@ static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry, * /proc/pid/fd needs a special permission handler so that a process can still * access /proc/self/fd after it has executed a setuid(). */ -int proc_fd_permission(struct inode *inode, int mask) +int proc_fd_permission(struct user_namespace *mnt_userns, + struct inode *inode, int mask) { struct task_struct *p; int rv; - rv = generic_permission(inode, mask); + rv = generic_permission(&init_user_ns, inode, mask); if (rv == 0) return rv; @@ -325,7 +332,7 @@ static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry, struct proc_inode *ei; struct inode *inode; - inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUSR); + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO); if (!inode) return ERR_PTR(-ENOENT); @@ -351,12 +358,23 @@ static int proc_readfdinfo(struct file *file, struct dir_context *ctx) proc_fdinfo_instantiate); } +static int proc_open_fdinfo(struct inode *inode, struct file *file) +{ + int ret = proc_fdinfo_access_allowed(inode); + + if (ret) + return ret; + + return 0; +} + const struct inode_operations proc_fdinfo_inode_operations = { .lookup = proc_lookupfdinfo, .setattr = proc_setattr, }; const struct file_operations proc_fdinfo_operations = { + .open = proc_open_fdinfo, .read = generic_read_dir, .iterate_shared = proc_readfdinfo, .llseek = generic_file_llseek, |