vfs: Fix /proc/<tid>/fdinfo/<fd> file handling

[cascardo/linux.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1c8b280..beda2b5 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -214,10 +214,10 @@ static int proc_pid_cmdline(struct task_struct *task, char * buffer)
                goto out_mm;    /* Shh! No looking before we're done */
 
        len = mm->arg_end - mm->arg_start;
- 
+
        if (len > PAGE_SIZE)
                len = PAGE_SIZE;
- 
+
        res = access_process_vm(task, mm->arg_start, buffer, len, 0);
 
        // If the nul at the end of args has been overwritten, then
@@ -1799,10 +1799,15 @@ static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
        if (task) {
                files = get_files_struct(task);
                if (files) {
+                       struct file *file;
                        rcu_read_lock();
-                       if (fcheck_files(files, fd)) {
+                       file = fcheck_files(files, fd);
+                       if (file) {
+                               unsigned f_mode = file->f_mode;
+
                                rcu_read_unlock();
                                put_files_struct(files);
+
                                if (task_dumpable(task)) {
                                        rcu_read_lock();
                                        cred = __task_cred(task);
@@ -1813,7 +1818,16 @@ static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
                                        inode->i_uid = 0;
                                        inode->i_gid = 0;
                                }
-                               inode->i_mode &= ~(S_ISUID | S_ISGID);
+
+                               if (S_ISLNK(inode->i_mode)) {
+                                       unsigned i_mode = S_IFLNK;
+                                       if (f_mode & FMODE_READ)
+                                               i_mode |= S_IRUSR | S_IXUSR;
+                                       if (f_mode & FMODE_WRITE)
+                                               i_mode |= S_IWUSR | S_IXUSR;
+                                       inode->i_mode = i_mode;
+                               }
+
                                security_task_to_inode(task, inode);
                                put_task_struct(task);
                                return 1;
@@ -1837,8 +1851,6 @@ static struct dentry *proc_fd_instantiate(struct inode *dir,
        struct dentry *dentry, struct task_struct *task, const void *ptr)
 {
        unsigned fd = *(const unsigned *)ptr;
-       struct file *file;
-       struct files_struct *files;
        struct inode *inode;
        struct proc_inode *ei;
        struct dentry *error = ERR_PTR(-ENOENT);
@@ -1848,26 +1860,8 @@ static struct dentry *proc_fd_instantiate(struct inode *dir,
                goto out;
        ei = PROC_I(inode);
        ei->fd = fd;
-       files = get_files_struct(task);
-       if (!files)
-               goto out_iput;
-       inode->i_mode = S_IFLNK;
-
-       /*
-        * We are not taking a ref to the file structure, so we must
-        * hold ->file_lock.
-        */
-       spin_lock(&files->file_lock);
-       file = fcheck_files(files, fd);
-       if (!file)
-               goto out_unlock;
-       if (file->f_mode & FMODE_READ)
-               inode->i_mode |= S_IRUSR | S_IXUSR;
-       if (file->f_mode & FMODE_WRITE)
-               inode->i_mode |= S_IWUSR | S_IXUSR;
-       spin_unlock(&files->file_lock);
-       put_files_struct(files);
 
+       inode->i_mode = S_IFLNK;
        inode->i_op = &proc_pid_link_inode_operations;
        inode->i_size = 64;
        ei->op.proc_get_link = proc_fd_link;
@@ -1879,12 +1873,6 @@ static struct dentry *proc_fd_instantiate(struct inode *dir,
 
  out:
        return error;
-out_unlock:
-       spin_unlock(&files->file_lock);
-       put_files_struct(files);
-out_iput:
-       iput(inode);
-       goto out;
 }
 
 static struct dentry *proc_lookupfd_common(struct inode *dir,
@@ -2177,16 +2165,16 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
                goto out;
 
        result = ERR_PTR(-EACCES);
-       if (lock_trace(task))
+       if (!ptrace_may_access(task, PTRACE_MODE_READ))
                goto out_put_task;
 
        result = ERR_PTR(-ENOENT);
        if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
-               goto out_unlock;
+               goto out_put_task;
 
        mm = get_task_mm(task);
        if (!mm)
-               goto out_unlock;
+               goto out_put_task;
 
        down_read(&mm->mmap_sem);
        vma = find_exact_vma(mm, vm_start, vm_end);
@@ -2198,8 +2186,6 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
 out_no_vma:
        up_read(&mm->mmap_sem);
        mmput(mm);
-out_unlock:
-       unlock_trace(task);
 out_put_task:
        put_task_struct(task);
 out:
@@ -2233,7 +2219,7 @@ proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
                goto out;
 
        ret = -EACCES;
-       if (lock_trace(task))
+       if (!ptrace_may_access(task, PTRACE_MODE_READ))
                goto out_put_task;
 
        ret = 0;
@@ -2241,12 +2227,12 @@ proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
        case 0:
                ino = inode->i_ino;
                if (filldir(dirent, ".", 1, 0, ino, DT_DIR) < 0)
-                       goto out_unlock;
+                       goto out_put_task;
                filp->f_pos++;
        case 1:
                ino = parent_ino(dentry);
                if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
-                       goto out_unlock;
+                       goto out_put_task;
                filp->f_pos++;
        default:
        {
@@ -2257,7 +2243,7 @@ proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
 
                mm = get_task_mm(task);
                if (!mm)
-                       goto out_unlock;
+                       goto out_put_task;
                down_read(&mm->mmap_sem);
 
                nr_files = 0;
@@ -2287,7 +2273,7 @@ proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
                                        flex_array_free(fa);
                                up_read(&mm->mmap_sem);
                                mmput(mm);
-                               goto out_unlock;
+                               goto out_put_task;
                        }
                        for (i = 0, vma = mm->mmap, pos = 2; vma;
                                        vma = vma->vm_next) {
@@ -2332,8 +2318,6 @@ proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
        }
        }
 
-out_unlock:
-       unlock_trace(task);
 out_put_task:
        put_task_struct(task);
 out:
@@ -2454,7 +2438,7 @@ out:
        return error;
 }
 
-static struct dentry *proc_pident_lookup(struct inode *dir, 
+static struct dentry *proc_pident_lookup(struct inode *dir,
                                         struct dentry *dentry,
                                         const struct pid_entry *ents,
                                         unsigned int nents)
@@ -3004,6 +2988,7 @@ static const struct pid_entry tgid_base_stuff[] = {
        REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
        REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
        REG("pagemap",    S_IRUGO, proc_pagemap_operations),
+       REG("totmaps",    S_IRUGO, proc_totmaps_operations),
 #endif
 #ifdef CONFIG_SECURITY
        DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),