From 18a4a87072ababf76ea08c8539e939b5b8a440ef Mon Sep 17 00:00:00 2001
From: Kees Cook<keescook@chromium.org>
Date: Thu, 10  Aug  2017  20:36:35  +0000
Subject: Revert "pstore: Honor dmesg_restrict sysctl on dmesg dumps"

PD#SWPL-7092
120501556
129462838

This reverts commit 68c4a4f8abc60c9440ede9cd123d48b78325f7a3, with
various conflict clean-ups.

With the default root directory mode set to 0750 now, the capability
check was redundant.

Change-Id: If978c34cef8345b0ba67a038eed7d54d4f1423d6
Suggested-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 1781dc5..3774856 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -121,18 +121,6 @@ static const struct seq_operations pstore_ftrace_seq_ops = {
 	.show	= pstore_ftrace_seq_show,
 };
 
-static int pstore_check_syslog_permissions(struct pstore_private *ps)
-{
-	switch (ps->type) {
-	case PSTORE_TYPE_DMESG:
-	case PSTORE_TYPE_CONSOLE:
-		return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
-			SYSLOG_FROM_READER);
-	default:
-		return 0;
-	}
-}
-
 static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
 						size_t count, loff_t *ppos)
 {
@@ -151,10 +139,6 @@ static int pstore_file_open(struct inode *inode, struct file *file)
 	int err;
 	const struct seq_operations *sops = NULL;
 
-	err = pstore_check_syslog_permissions(ps);
-	if (err)
-		return err;
-
 	if (ps->type == PSTORE_TYPE_FTRACE)
 		sops = &pstore_ftrace_seq_ops;
 
@@ -191,11 +175,6 @@ static const struct file_operations pstore_file_operations = {
 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct pstore_private *p = d_inode(dentry)->i_private;
-	int err;
-
-	err = pstore_check_syslog_permissions(p);
-	if (err)
-		return err;
 
 	if (p->psi->erase)
 		p->psi->erase(p->type, p->id, p->count,
diff --git a/include/linux/syslog.h b/include/linux/syslog.h
index c3a7f0c..e1c3632 100644
--- a/include/linux/syslog.h
+++ b/include/linux/syslog.h
@@ -49,13 +49,4 @@
 
 int do_syslog(int type, char __user *buf, int count, int source);
 
-#ifdef CONFIG_PRINTK
-int check_syslog_permissions(int type, int source);
-#else
-static inline int check_syslog_permissions(int type, int source)
-{
-	return 0;
-}
-#endif
-
 #endif /* _LINUX_SYSLOG_H */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 8e23615..b67e84c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -615,7 +615,7 @@ static int syslog_action_restricted(int type)
 	       type != SYSLOG_ACTION_SIZE_BUFFER;
 }
 
-int check_syslog_permissions(int type, int source)
+static int check_syslog_permissions(int type, int source)
 {
 	/*
 	 * If this is from /proc/kmsg and we've already opened it, then we've
@@ -643,7 +643,6 @@ int check_syslog_permissions(int type, int source)
 ok:
 	return security_syslog(type);
 }
-EXPORT_SYMBOL_GPL(check_syslog_permissions);
 
 static void append_char(char **pp, char *e, char c)
 {
--
cgit