From 0e1a6ef2dea88101b056b6d9984f3325c5efced3 Mon Sep 17 00:00:00 2001
From: Kees Cook <kees.cook@canonical.com>
Date: Sun, 8 Nov 2009 09:37:00 -0800
Subject: [PATCH] sysctl: require CAP_SYS_RAWIO to set mmap_min_addr
Currently the mmap_min_addr value can only be bypassed during mmap when
the task has CAP_SYS_RAWIO. However, the mmap_min_addr sysctl value itself
can be adjusted to 0 if euid == 0, allowing a bypass without CAP_SYS_RAWIO.
This patch adds a check for the capability before allowing mmap_min_addr to
be changed.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
---
security/min_addr.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/security/min_addr.c b/security/min_addr.c
index c844eed7915d..fc43c9d37084 100644
--- a/security/min_addr.c
+++ b/security/min_addr.c
@@ -33,6 +33,9 @@ int mmap_min_addr_handler(struct ctl_table *table, int write,
{
int ret;
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
update_mmap_min_addr();
--
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