diff options
Diffstat (limited to 'fs/proc/base.c')
| -rw-r--r-- | fs/proc/base.c | 77 |
1 files changed, 61 insertions, 16 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 0d163a84082d..a11eb7196ec8 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1820,12 +1820,17 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx, child = d_hash_and_lookup(dir, &qname); if (!child) { - child = d_alloc(dir, &qname); - if (!child) - goto end_instantiate; - if (instantiate(d_inode(dir), child, task, ptr) < 0) { - dput(child); + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + child = d_alloc_parallel(dir, &qname, &wq); + if (IS_ERR(child)) goto end_instantiate; + if (d_in_lookup(child)) { + int err = instantiate(d_inode(dir), child, task, ptr); + d_lookup_done(child); + if (err < 0) { + dput(child); + goto end_instantiate; + } } } inode = d_inode(child); @@ -2155,8 +2160,8 @@ out: static const struct file_operations proc_map_files_operations = { .read = generic_read_dir, - .iterate = proc_map_files_readdir, - .llseek = default_llseek, + .iterate_shared = proc_map_files_readdir, + .llseek = generic_file_llseek, }; #ifdef CONFIG_CHECKPOINT_RESTORE @@ -2503,8 +2508,8 @@ static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx) static const struct file_operations proc_attr_dir_operations = { .read = generic_read_dir, - .iterate = proc_attr_dir_readdir, - .llseek = default_llseek, + .iterate_shared = proc_attr_dir_readdir, + .llseek = generic_file_llseek, }; static struct dentry *proc_attr_dir_lookup(struct inode *dir, @@ -2911,8 +2916,8 @@ static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx) static const struct file_operations proc_tgid_base_operations = { .read = generic_read_dir, - .iterate = proc_tgid_base_readdir, - .llseek = default_llseek, + .iterate_shared = proc_tgid_base_readdir, + .llseek = generic_file_llseek, }; static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) @@ -3158,6 +3163,44 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx) } /* + * proc_tid_comm_permission is a special permission function exclusively + * used for the node /proc/<pid>/task/<tid>/comm. + * It bypasses generic permission checks in the case where a task of the same + * task group attempts to access the node. + * The rationale behind this is that glibc and bionic access this node for + * cross thread naming (pthread_set/getname_np(!self)). However, if + * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0, + * which locks out the cross thread naming implementation. + * This function makes sure that the node is always accessible for members of + * same thread group. + */ +static int proc_tid_comm_permission(struct inode *inode, int mask) +{ + bool is_same_tgroup; + struct task_struct *task; + + task = get_proc_task(inode); + if (!task) + return -ESRCH; + is_same_tgroup = same_thread_group(current, task); + put_task_struct(task); + + if (likely(is_same_tgroup && !(mask & MAY_EXEC))) { + /* This file (/proc/<pid>/task/<tid>/comm) can always be + * read or written by the members of the corresponding + * thread group. + */ + return 0; + } + + return generic_permission(inode, mask); +} + +static const struct inode_operations proc_tid_comm_inode_operations = { + .permission = proc_tid_comm_permission, +}; + +/* * Tasks */ static const struct pid_entry tid_base_stuff[] = { @@ -3175,7 +3218,9 @@ static const struct pid_entry tid_base_stuff[] = { #ifdef CONFIG_SCHED_DEBUG REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations), #endif - REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations), + NOD("comm", S_IFREG|S_IRUGO|S_IWUSR, + &proc_tid_comm_inode_operations, + &proc_pid_set_comm_operations, {}), #ifdef CONFIG_HAVE_ARCH_TRACEHOOK ONE("syscall", S_IRUSR, proc_pid_syscall), #endif @@ -3259,8 +3304,8 @@ static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *den static const struct file_operations proc_tid_base_operations = { .read = generic_read_dir, - .iterate = proc_tid_base_readdir, - .llseek = default_llseek, + .iterate_shared = proc_tid_base_readdir, + .llseek = generic_file_llseek, }; static const struct inode_operations proc_tid_base_inode_operations = { @@ -3470,6 +3515,6 @@ static const struct inode_operations proc_task_inode_operations = { static const struct file_operations proc_task_operations = { .read = generic_read_dir, - .iterate = proc_task_readdir, - .llseek = default_llseek, + .iterate_shared = proc_task_readdir, + .llseek = generic_file_llseek, }; |