From: Kees Cook <keescook@chromium.org>
Date: Wed, 4 Apr 2012 18:40:19 +0000 (-0700)
Subject: sysctl: fix write access to dmesg_restrict/kptr_restrict
X-Git-Tag: v3.0.28~15
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=41ae97bd8c2166184bf0552b7c41868b74344039;p=karo-tx-linux.git

sysctl: fix write access to dmesg_restrict/kptr_restrict

commit 620f6e8e855d6d447688a5f67a4e176944a084e8 upstream.

Commit bfdc0b4 adds code to restrict access to dmesg_restrict,
however, it incorrectly alters kptr_restrict rather than
dmesg_restrict.

The original patch from Richard Weinberger
(https://lkml.org/lkml/2011/3/14/362) alters dmesg_restrict as
expected, and so the patch seems to have been misapplied.

This adds the CAP_SYS_ADMIN check to both dmesg_restrict and
kptr_restrict, since both are sensitive.

Reported-by: Phillip Lougher <plougher@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index f175d98bd355..aaaa7e749adb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -172,7 +172,7 @@ static int proc_taint(struct ctl_table *table, int write,
 #endif
 
 #ifdef CONFIG_PRINTK
-static int proc_dmesg_restrict(struct ctl_table *table, int write,
+static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,
 				void __user *buffer, size_t *lenp, loff_t *ppos);
 #endif
 
@@ -709,7 +709,7 @@ static struct ctl_table kern_table[] = {
 		.data		= &dmesg_restrict,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dointvec_minmax_sysadmin,
 		.extra1		= &zero,
 		.extra2		= &one,
 	},
@@ -718,7 +718,7 @@ static struct ctl_table kern_table[] = {
 		.data		= &kptr_restrict,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dmesg_restrict,
+		.proc_handler	= proc_dointvec_minmax_sysadmin,
 		.extra1		= &zero,
 		.extra2		= &two,
 	},
@@ -2416,7 +2416,7 @@ static int proc_taint(struct ctl_table *table, int write,
 }
 
 #ifdef CONFIG_PRINTK
-static int proc_dmesg_restrict(struct ctl_table *table, int write,
+static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,
 				void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (write && !capable(CAP_SYS_ADMIN))