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

7 files changed, 12 insertions, 12 deletions

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index 2761c8613..b3af6a759 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -175,7 +175,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 
 	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() & ((1 << 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 8af07b65e..8f6bcc3f4 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -54,10 +54,10 @@ static unsigned long mmap_rnd(void)
 	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 7e5fe2790..358820ba6 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -147,7 +147,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 	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 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 
 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 d55357ee9..9310b80cf 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1450,9 +1450,9 @@ static inline unsigned long brk_rnd(void)
 
 	/* 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() % (1<<(30-PAGE_SHIFT)));
 
 	return rnd << PAGE_SHIFT;
 }
diff --git a/arch/powerpc/mm/mmap_64.c b/arch/powerpc/mm/mmap_64.c
index 67a42ed0d..344fbe75e 100644
--- a/arch/powerpc/mm/mmap_64.c
+++ b/arch/powerpc/mm/mmap_64.c
@@ -60,9 +60,9 @@ static unsigned long mmap_rnd(void)
 	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() % (1<<(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 666510b39..c2c11c7d7 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -265,7 +265,7 @@ static unsigned long mmap_rnd(void)
 	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 75f9e5d80..d4fa45822 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -75,9 +75,9 @@ static unsigned long mmap_rnd(void)
 	*/
 	if (current->flags & PF_RANDOMIZE) {
 		if (mmap_is_ia32())
-			rnd = get_random_int() % (1<<8);
+			rnd = get_random_long() % (1<<8);
 		else
-			rnd = get_random_int() % (1<<28);
+			rnd = get_random_long() % (1<<28);
 	}
 	return rnd << PAGE_SHIFT;
 }