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yaml
---
r: 146447
b: refs/heads/master
c: e0a94c2
h: refs/heads/master
i:
  146445: e857e45
  146443: c033bf3
  146439: 5931549
  146431: 943ba7b
v: v3
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Christoph Lameter authored and James Morris committed Jun 4, 2009
1 parent d9627eb commit 39e7450
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Showing 8 changed files with 26 additions and 29 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 7d2948b1248109dbc7f4aaf9867c54b1912d494c
refs/heads/master: e0a94c2a63f2644826069044649669b5e7ca75d3
2 changes: 0 additions & 2 deletions trunk/include/linux/mm.h
Original file line number Diff line number Diff line change
Expand Up @@ -580,12 +580,10 @@ static inline void set_page_links(struct page *page, enum zone_type zone,
*/
static inline unsigned long round_hint_to_min(unsigned long hint)
{
#ifdef CONFIG_SECURITY
hint &= PAGE_MASK;
if (((void *)hint != NULL) &&
(hint < mmap_min_addr))
return PAGE_ALIGN(mmap_min_addr);
#endif
return hint;
}

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2 changes: 2 additions & 0 deletions trunk/include/linux/security.h
Original file line number Diff line number Diff line change
Expand Up @@ -2197,6 +2197,8 @@ static inline int security_file_mmap(struct file *file, unsigned long reqprot,
unsigned long addr,
unsigned long addr_only)
{
if ((addr < mmap_min_addr) && !capable(CAP_SYS_RAWIO))
return -EACCES;
return 0;
}

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2 changes: 0 additions & 2 deletions trunk/kernel/sysctl.c
Original file line number Diff line number Diff line change
Expand Up @@ -1237,7 +1237,6 @@ static struct ctl_table vm_table[] = {
.strategy = &sysctl_jiffies,
},
#endif
#ifdef CONFIG_SECURITY
{
.ctl_name = CTL_UNNUMBERED,
.procname = "mmap_min_addr",
Expand All @@ -1246,7 +1245,6 @@ static struct ctl_table vm_table[] = {
.mode = 0644,
.proc_handler = &proc_doulongvec_minmax,
},
#endif
#ifdef CONFIG_NUMA
{
.ctl_name = CTL_UNNUMBERED,
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19 changes: 19 additions & 0 deletions trunk/mm/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -226,6 +226,25 @@ config HAVE_MLOCKED_PAGE_BIT
config MMU_NOTIFIER
bool

config DEFAULT_MMAP_MIN_ADDR
int "Low address space to protect from user allocation"
default 4096
help
This is the portion of low virtual memory which should be protected
from userspace allocation. Keeping a user from writing to low pages
can help reduce the impact of kernel NULL pointer bugs.

For most ia64, ppc64 and x86 users with lots of address space
a value of 65536 is reasonable and should cause no problems.
On arm and other archs it should not be higher than 32768.
Programs which use vm86 functionality would either need additional
permissions from either the LSM or the capabilities module or have
this protection disabled.

This value can be changed after boot using the
/proc/sys/vm/mmap_min_addr tunable.


config NOMMU_INITIAL_TRIM_EXCESS
int "Turn on mmap() excess space trimming before booting"
depends on !MMU
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3 changes: 3 additions & 0 deletions trunk/mm/mmap.c
Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,9 @@ int sysctl_overcommit_ratio = 50; /* default is 50% */
int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
struct percpu_counter vm_committed_as;

/* amount of vm to protect from userspace access */
unsigned long mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;

/*
* Check that a process has enough memory to allocate a new virtual
* mapping. 0 means there is enough memory for the allocation to
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22 changes: 1 addition & 21 deletions trunk/security/Kconfig
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Expand Up @@ -110,28 +110,8 @@ config SECURITY_ROOTPLUG

See <http://www.linuxjournal.com/article.php?sid=6279> for
more information about this module.

If you are unsure how to answer this question, answer N.

config SECURITY_DEFAULT_MMAP_MIN_ADDR
int "Low address space to protect from user allocation"
depends on SECURITY
default 0
help
This is the portion of low virtual memory which should be protected
from userspace allocation. Keeping a user from writing to low pages
can help reduce the impact of kernel NULL pointer bugs.

For most ia64, ppc64 and x86 users with lots of address space
a value of 65536 is reasonable and should cause no problems.
On arm and other archs it should not be higher than 32768.
Programs which use vm86 functionality would either need additional
permissions from either the LSM or the capabilities module or have
this protection disabled.

This value can be changed after boot using the
/proc/sys/vm/mmap_min_addr tunable.

If you are unsure how to answer this question, answer N.

source security/selinux/Kconfig
source security/smack/Kconfig
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3 changes: 0 additions & 3 deletions trunk/security/security.c
Original file line number Diff line number Diff line change
Expand Up @@ -26,9 +26,6 @@ extern void security_fixup_ops(struct security_operations *ops);

struct security_operations *security_ops; /* Initialized to NULL */

/* amount of vm to protect from userspace access */
unsigned long mmap_min_addr = CONFIG_SECURITY_DEFAULT_MMAP_MIN_ADDR;

static inline int verify(struct security_operations *ops)
{
/* verify the security_operations structure exists */
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