1 files changed, 45 insertions, 68 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index aa50d1ac28fc..b25eee4cead5 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1230,10 +1230,9 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 				   size_t count, loff_t *ppos)
 {
 	struct inode * inode = file_inode(file);
-	char *page, *tmp;
-	ssize_t length;
 	uid_t loginuid;
 	kuid_t kloginuid;
+	int rv;
 
 	rcu_read_lock();
 	if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
@@ -1242,46 +1241,28 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 	}
 	rcu_read_unlock();
 
-	if (count >= PAGE_SIZE)
-		count = PAGE_SIZE - 1;
-
 	if (*ppos != 0) {
 		/* No partial writes. */
 		return -EINVAL;
 	}
-	page = (char*)__get_free_page(GFP_TEMPORARY);
-	if (!page)
-		return -ENOMEM;
-	length = -EFAULT;
-	if (copy_from_user(page, buf, count))
-		goto out_free_page;
-
-	page[count] = '\0';
-	loginuid = simple_strtoul(page, &tmp, 10);
-	if (tmp == page) {
-		length = -EINVAL;
-		goto out_free_page;
 
-	}
+	rv = kstrtou32_from_user(buf, count, 10, &loginuid);
+	if (rv < 0)
+		return rv;
 
 	/* is userspace tring to explicitly UNSET the loginuid? */
 	if (loginuid == AUDIT_UID_UNSET) {
 		kloginuid = INVALID_UID;
 	} else {
 		kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
-		if (!uid_valid(kloginuid)) {
-			length = -EINVAL;
-			goto out_free_page;
-		}
+		if (!uid_valid(kloginuid))
+			return -EINVAL;
 	}
 
-	length = audit_set_loginuid(kloginuid);
-	if (likely(length == 0))
-		length = count;
-
-out_free_page:
-	free_page((unsigned long) page);
-	return length;
+	rv = audit_set_loginuid(kloginuid);
+	if (rv < 0)
+		return rv;
+	return count;
 }
 
 static const struct file_operations proc_loginuid_operations = {
@@ -1335,8 +1316,9 @@ static ssize_t proc_fault_inject_write(struct file * file,
 			const char __user * buf, size_t count, loff_t *ppos)
 {
 	struct task_struct *task;
-	char buffer[PROC_NUMBUF], *end;
+	char buffer[PROC_NUMBUF];
 	int make_it_fail;
+	int rv;
 
 	if (!capable(CAP_SYS_RESOURCE))
 		return -EPERM;
@@ -1345,9 +1327,9 @@ static ssize_t proc_fault_inject_write(struct file * file,
 		count = sizeof(buffer) - 1;
 	if (copy_from_user(buffer, buf, count))
 		return -EFAULT;
-	make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
-	if (*end)
-		return -EINVAL;
+	rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
+	if (rv < 0)
+		return rv;
 	if (make_it_fail < 0 || make_it_fail > 1)
 		return -EINVAL;
 
@@ -1836,8 +1818,6 @@ end_instantiate:
 	return dir_emit(ctx, name, len, 1, DT_UNKNOWN);
 }
 
-#ifdef CONFIG_CHECKPOINT_RESTORE
-
 /*
  * dname_to_vma_addr - maps a dentry name into two unsigned longs
  * which represent vma start and end addresses.
@@ -1864,11 +1844,6 @@ static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
 
-	if (!capable(CAP_SYS_ADMIN)) {
-		status = -EPERM;
-		goto out_notask;
-	}
-
 	inode = d_inode(dentry);
 	task = get_proc_task(inode);
 	if (!task)
@@ -1957,6 +1932,29 @@ struct map_files_info {
 	unsigned char	name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
 };
 
+/*
+ * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
+ * symlinks may be used to bypass permissions on ancestor directories in the
+ * path to the file in question.
+ */
+static const char *
+proc_map_files_follow_link(struct dentry *dentry, void **cookie)
+{
+	if (!capable(CAP_SYS_ADMIN))
+		return ERR_PTR(-EPERM);
+
+	return proc_pid_follow_link(dentry, NULL);
+}
+
+/*
+ * Identical to proc_pid_link_inode_operations except for follow_link()
+ */
+static const struct inode_operations proc_map_files_link_inode_operations = {
+	.readlink	= proc_pid_readlink,
+	.follow_link	= proc_map_files_follow_link,
+	.setattr	= proc_setattr,
+};
+
 static int
 proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
 			   struct task_struct *task, const void *ptr)
@@ -1972,7 +1970,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
 	ei = PROC_I(inode);
 	ei->op.proc_get_link = proc_map_files_get_link;
 
-	inode->i_op = &proc_pid_link_inode_operations;
+	inode->i_op = &proc_map_files_link_inode_operations;
 	inode->i_size = 64;
 	inode->i_mode = S_IFLNK;
 
@@ -1996,10 +1994,6 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
 	int result;
 	struct mm_struct *mm;
 
-	result = -EPERM;
-	if (!capable(CAP_SYS_ADMIN))
-		goto out;
-
 	result = -ENOENT;
 	task = get_proc_task(dir);
 	if (!task)
@@ -2053,10 +2047,6 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
 	struct map_files_info *p;
 	int ret;
 
-	ret = -EPERM;
-	if (!capable(CAP_SYS_ADMIN))
-		goto out;
-
 	ret = -ENOENT;
 	task = get_proc_task(file_inode(file));
 	if (!task)
@@ -2245,7 +2235,6 @@ static const struct file_operations proc_timers_operations = {
 	.llseek		= seq_lseek,
 	.release	= seq_release_private,
 };
-#endif /* CONFIG_CHECKPOINT_RESTORE */
 
 static int proc_pident_instantiate(struct inode *dir,
 	struct dentry *dentry, struct task_struct *task, const void *ptr)
@@ -2481,32 +2470,20 @@ static ssize_t proc_coredump_filter_write(struct file *file,
 {
 	struct task_struct *task;
 	struct mm_struct *mm;
-	char buffer[PROC_NUMBUF], *end;
 	unsigned int val;
 	int ret;
 	int i;
 	unsigned long mask;
 
-	ret = -EFAULT;
-	memset(buffer, 0, sizeof(buffer));
-	if (count > sizeof(buffer) - 1)
-		count = sizeof(buffer) - 1;
-	if (copy_from_user(buffer, buf, count))
-		goto out_no_task;
-
-	ret = -EINVAL;
-	val = (unsigned int)simple_strtoul(buffer, &end, 0);
-	if (*end == '\n')
-		end++;
-	if (end - buffer == 0)
-		goto out_no_task;
+	ret = kstrtouint_from_user(buf, count, 0, &val);
+	if (ret < 0)
+		return ret;
 
 	ret = -ESRCH;
 	task = get_proc_task(file_inode(file));
 	if (!task)
 		goto out_no_task;
 
-	ret = end - buffer;
 	mm = get_task_mm(task);
 	if (!mm)
 		goto out_no_mm;
@@ -2522,7 +2499,9 @@ static ssize_t proc_coredump_filter_write(struct file *file,
  out_no_mm:
 	put_task_struct(task);
  out_no_task:
-	return ret;
+	if (ret < 0)
+		return ret;
+	return count;
 }
 
 static const struct file_operations proc_coredump_filter_operations = {
@@ -2744,9 +2723,7 @@ static const struct inode_operations proc_task_inode_operations;
 static const struct pid_entry tgid_base_stuff[] = {
 	DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
 	DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
-#ifdef CONFIG_CHECKPOINT_RESTORE
 	DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
-#endif
 	DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
 	DIR("ns",	  S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
 #ifdef CONFIG_NET