rpms/kernel/devel linux-2.6.31-nx-data.patch, NONE, 1.1 kernel.spec, 1.1794, 1.1795
Dave Jones
davej at fedoraproject.org
Fri Sep 11 15:31:53 UTC 2009
Author: davej
Update of /cvs/pkgs/rpms/kernel/devel
In directory cvs1.fedora.phx.redhat.com:/tmp/cvs-serv13951
Modified Files:
kernel.spec
Added Files:
linux-2.6.31-nx-data.patch
Log Message:
Mark kernel data section as NX
linux-2.6.31-nx-data.patch:
kernel/vmlinux.lds.S | 6 +++++-
mm/init.c | 22 ++++++++++++++++++++--
2 files changed, 25 insertions(+), 3 deletions(-)
--- NEW FILE linux-2.6.31-nx-data.patch ---
Date: Thu, 10 Sep 2009 21:10:51 -0400
Message-ID: <817ecb6f0909101810u7774ca93u40a0a4b99f9fb6ba at mail.gmail.com>
Subject: [PATCH V4] x86: NX protection for kernel data
From: Siarhei Liakh <sliakh.lkml at gmail.com>
To: linux-kernel at vger.kernel.org, linux-security-module at vger.kernel.org
Cc: Arjan van de Ven <arjan at infradead.org>, James Morris <jmorris at namei.org>,
Andrew Morton <akpm at linux-foundation.org>, Andi Kleen <ak at muc.de>,
Rusty Russell <rusty at rustcorp.com.au>,
Thomas Gleixner <tglx at linutronix.de>, "H. Peter Anvin" <hpa at zytor.com>,
Ingo Molnar <mingo at elte.hu>
This patch expands functionality of CONFIG_DEBUG_RODATA to set main
(static) kernel data area as NX.
The following steps are taken to achieve this:
1. Linker script is adjusted so .text always starts and ends on a page boundary
2. Linker script is adjusted so .rodata and .data always start and
end on a page boundary
3. void mark_nxdata_nx(void) added to arch/x86/mm/init.c with actual
functionality: NX is set for all pages from _etext through _end.
4. mark_nxdata_nx() called from free_initmem() (after init has been released)
5. free_init_pages() sets released memory NX in arch/x86/mm/init.c
The patch have been developed for Linux 2.6.31-rc7 x86 by Siarhei Liakh
<sliakh.lkml at gmail.com> and Xuxian Jiang <jiang at cs.ncsu.edu>.
V1: initial patch for 2.6.30
V2: patch for 2.6.31-rc7
V3: moved all code into arch/x86, adjusted credits
V4: fixed ifdef, removed credits from CREDITS
---
Signed-off-by: Siarhei Liakh <sliakh.lkml at gmail.com>
Signed-off-by: Xuxian Jiang <jiang at cs.ncsu.edu>
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 9fc1782..b6b2bbf 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -43,7 +43,7 @@ jiffies_64 = jiffies;
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
- data PT_LOAD FLAGS(7); /* RWE */
+ data PT_LOAD FLAGS(6); /* RW_ */
#ifdef CONFIG_X86_64
user PT_LOAD FLAGS(7); /* RWE */
#ifdef CONFIG_SMP
@@ -88,6 +88,8 @@ SECTIONS
IRQENTRY_TEXT
*(.fixup)
*(.gnu.warning)
+ /* .text should occupy whole number of pages */
+ . = ALIGN(PAGE_SIZE);
/* End of text section */
_etext = .;
} :text = 0x9090
@@ -128,6 +130,8 @@ SECTIONS
/* rarely changed data like cpu maps */
READ_MOSTLY_DATA(CONFIG_X86_INTERNODE_CACHE_BYTES)
+ /* .data should occupy whole number of pages */
+ . = ALIGN(PAGE_SIZE);
/* End of data section */
_edata = .;
} :data
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 0607119..522e81b 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -423,9 +423,10 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
/*
* We just marked the kernel text read only above, now that
* we are going to free part of that, we need to make that
- * writeable first.
+ * writeable and non-executable first.
*/
set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
+ set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
@@ -440,11 +441,29 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
#endif
}
+void mark_nxdata_nx(void)
+{
+#ifdef CONFIG_DEBUG_RODATA
+ /*
+ * When this called, init has already been executed and released,
+ * so everything past _etext sould be NX.
+ */
+ unsigned long start = PFN_ALIGN(_etext);
+ unsigned long size = PFN_ALIGN(_end) - start;
+
+ printk(KERN_INFO "NX-protecting the kernel data: %lx, %lu pages\n",
+ start, size >> PAGE_SHIFT);
+ set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT);
+#endif
+}
+
void free_initmem(void)
{
free_init_pages("unused kernel memory",
(unsigned long)(&__init_begin),
(unsigned long)(&__init_end));
+ /* Set kernel's data as NX */
+ mark_nxdata_nx();
}
#ifdef CONFIG_BLK_DEV_INITRD
--
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Index: kernel.spec
===================================================================
RCS file: /cvs/pkgs/rpms/kernel/devel/kernel.spec,v
retrieving revision 1.1794
retrieving revision 1.1795
diff -u -p -r1.1794 -r1.1795
--- kernel.spec 11 Sep 2009 07:05:08 -0000 1.1794
+++ kernel.spec 11 Sep 2009 15:31:52 -0000 1.1795
@@ -667,6 +667,8 @@ Patch671: linux-2.6-ahci-export-capabili
Patch680: linux-2.6-rt2x00-asus-leds.patch
Patch681: linux-2.6-mac80211-age-scan-results-on-resume.patch
+Patch700: linux-2.6.31-nx-data.patch
+
Patch800: linux-2.6-crash-driver.patch
Patch900: linux-2.6-pci-cacheline-sizing.patch
@@ -1295,6 +1297,9 @@ ApplyPatch linux-2.6-ahci-export-capabil
# back-port scan result aging patches
#ApplyPatch linux-2.6-mac80211-age-scan-results-on-resume.patch
+# Mark kernel data as NX
+ApplyPatch linux-2.6.31-nx-data.patch
+
# /dev/crash driver.
ApplyPatch linux-2.6-crash-driver.patch
@@ -2018,6 +2023,9 @@ fi
# and build.
%changelog
+* Fri Sep 11 2009 Dave Jones <davej at redhat.com>
+- Mark kernel data section as NX
+
* Fri Sep 11 2009 Ben Skeggs <bskeggs at redhat.com>
- nouveau: bring in Matthew Garret's initial switchable graphics support
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