BACKPORT: FROMLIST: mm: ASLR: use get_random_long()
(cherry picked from commit https://lkml.org/lkml/2016/2/4/833)
Replace calls to get_random_int() followed by a cast to (unsigned long)
with calls to get_random_long(). Also address shifting bug which, in case
of x86 removed entropy mask for mmap_rnd_bits values > 31 bits.
Bug: 26963541
Signed-off-by: Daniel Cashman <dcashman@android.com>
Signed-off-by: Daniel Cashman <dcashman@google.com>
Change-Id: Ie577b21a0678cf4b21eae06bddd8ccb27cbe70ff
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index def1682..ea331cf 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -175,7 +175,7 @@
if ((current->flags & PF_RANDOMIZE) &&
!(current->personality & ADDR_NO_RANDOMIZE))
- random_factor = (get_random_int() & ((1 << mmap_rnd_bits) - 1)) << PAGE_SHIFT;
+ random_factor = (get_random_long() & ((1UL << mmap_rnd_bits) - 1)) << PAGE_SHIFT;
if (mmap_is_legacy()) {
mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index 8af07b6..83c3df2 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -54,10 +54,10 @@
if (current->flags & PF_RANDOMIZE) {
#ifdef CONFIG_COMPAT
if (test_thread_flag(TIF_32BIT))
- rnd = (unsigned long)get_random_int() & ((1 << mmap_rnd_compat_bits) - 1);
+ rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
else
#endif
- rnd = (unsigned long)get_random_int() & ((1 << mmap_rnd_bits) - 1);
+ rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
}
return rnd << PAGE_SHIFT;
}
diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index 7e5fe27..358820b 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -147,7 +147,7 @@
unsigned long random_factor = 0UL;
if (current->flags & PF_RANDOMIZE) {
- random_factor = get_random_int();
+ random_factor = get_random_long();
random_factor = random_factor << PAGE_SHIFT;
if (TASK_IS_32BIT_ADDR)
random_factor &= 0xfffffful;
@@ -168,7 +168,7 @@
static inline unsigned long brk_rnd(void)
{
- unsigned long rnd = get_random_int();
+ unsigned long rnd = get_random_long();
rnd = rnd << PAGE_SHIFT;
/* 8MB for 32bit, 256MB for 64bit */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 076d124..8bd362d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1408,9 +1408,9 @@
/* 8MB for 32bit, 1GB for 64bit */
if (is_32bit_task())
- rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
+ rnd = (get_random_long() % (1UL<<(23-PAGE_SHIFT)));
else
- rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
+ rnd = (get_random_long() % (1UL<<(30-PAGE_SHIFT)));
return rnd << PAGE_SHIFT;
}
diff --git a/arch/powerpc/mm/mmap_64.c b/arch/powerpc/mm/mmap_64.c
index 67a42ed..2803d90 100644
--- a/arch/powerpc/mm/mmap_64.c
+++ b/arch/powerpc/mm/mmap_64.c
@@ -60,9 +60,9 @@
if (current->flags & PF_RANDOMIZE) {
/* 8MB for 32bit, 1GB for 64bit */
if (is_32bit_task())
- rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
+ rnd = get_random_long() % (1<<(23-PAGE_SHIFT));
else
- rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
+ rnd = get_random_long() % (1UL<<(30-PAGE_SHIFT));
}
return rnd << PAGE_SHIFT;
}
diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 2daaaa6..1e9e320 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -265,7 +265,7 @@
unsigned long rnd = 0UL;
if (current->flags & PF_RANDOMIZE) {
- unsigned long val = get_random_int();
+ unsigned long val = get_random_long();
if (test_thread_flag(TIF_32BIT))
rnd = (val % (1UL << (23UL-PAGE_SHIFT)));
else
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index 1b3485a..48d6bc8 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -72,12 +72,12 @@
if (current->flags & PF_RANDOMIZE) {
if (mmap_is_ia32())
#ifdef CONFIG_COMPAT
- rnd = (unsigned long)get_random_int() & ((1 << mmap_rnd_compat_bits) - 1);
+ rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
#else
- rnd = (unsigned long)get_random_int() & ((1 << mmap_rnd_bits) - 1);
+ rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
#endif
else
- rnd = (unsigned long)get_random_int() & ((1 << mmap_rnd_bits) - 1);
+ rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
}
return rnd << PAGE_SHIFT;
}
