From 8cf948e744e0218af604c32edecde10006dc8e9e Mon Sep 17 00:00:00 2001
From: Eric Paris <eparis@redhat.com>
Date: Fri, 31 Jul 2009 12:54:05 -0400
Subject: [PATCH] SELinux: call cap_file_mmap in selinux_file_mmap
Currently SELinux does not check CAP_SYS_RAWIO in the file_mmap hook. This
means there is no DAC check on the ability to mmap low addresses in the
memory space. This function adds the DAC check for CAP_SYS_RAWIO while
maintaining the selinux check on mmap_zero. This means that processes
which need to mmap low memory will need CAP_SYS_RAWIO and mmap_zero but will
NOT need the SELinux sys_rawio capability.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
---
security/selinux/hooks.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 1e8cfc4c2ed6..e6d1432b0800 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3030,9 +3030,21 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
int rc = 0;
u32 sid = current_sid();
- if (addr < mmap_min_addr)
+ /*
+ * notice that we are intentionally putting the SELinux check before
+ * the secondary cap_file_mmap check. This is such a likely attempt
+ * at bad behaviour/exploit that we always want to get the AVC, even
+ * if DAC would have also denied the operation.
+ */
+ if (addr < mmap_min_addr) {
rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
MEMPROTECT__MMAP_ZERO, NULL);
+ if (rc)
+ return rc;
+ }
+
+ /* do DAC check on address space usage */
+ rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
if (rc || addr_only)
return rc;
--
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