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: I36c156c9b8d7d157134895fddd4cd6efddcbee86

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index 4b4058db0781f63e307d4f5101a74d5330ddf337..66353caa35b9f78fa2aa4754dea3ce813593303f 100644 (file)
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -173,7 +173,7 @@ unsigned long arch_mmap_rnd(void)
 {
        unsigned long rnd;
 
-       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/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index 4c893b5189ddd027537511c5daaca70f158577c4..232f787a088ae8e992c52cba450159a43a900174 100644 (file)
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -53,10 +53,10 @@ unsigned long arch_mmap_rnd(void)
 
 #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 5c81fdd032c3b1269549f27e27348e9606eb5424..353037699512ca5515b11ce8fb2c808eb6386c78 100644 (file)
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -146,7 +146,7 @@ unsigned long arch_mmap_rnd(void)
 {
        unsigned long rnd;
 
-       rnd = (unsigned long)get_random_int();
+       rnd = get_random_long();
        rnd <<= PAGE_SHIFT;
        if (TASK_IS_32BIT_ADDR)
                rnd &= 0xfffffful;
@@ -174,7 +174,7 @@ 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 ef2ad2d682dae74f97598fa4a789b59058368a29..36795d1e75586aa523f2c55ffabc09baeb1562f1 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1659,9 +1659,9 @@ 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() % (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.c b/arch/powerpc/mm/mmap.c
index 0f0502e12f6c4c8accbe7fc28eb4db08158decfb..4087705ba90f34241200e2f30765794ea6b74b55 100644 (file)
--- a/arch/powerpc/mm/mmap.c
+++ b/arch/powerpc/mm/mmap.c
@@ -59,9 +59,9 @@ unsigned long arch_mmap_rnd(void)
 
        /* 8MB for 32bit, 1GB for 64bit */
        if (is_32bit_task())
-               rnd = (unsigned long)get_random_int() % (1<<(23-PAGE_SHIFT));
+               rnd = get_random_long() % (1<<(23-PAGE_SHIFT));
        else
-               rnd = (unsigned 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 c690c8e16a96ef2758fca4e9af8080ec7af6c17a..b489e9759518182b6a3884935e5a1c22b1af3524 100644 (file)
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -264,7 +264,7 @@ 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 96bd1e2bffafb3b8ffbc28906a2998ad992d50e8..72bb52f93c3d619d0dc6c0355b7ab293a24c3199 100644 (file)
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -71,12 +71,12 @@ unsigned long arch_mmap_rnd(void)
 
        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;
 }

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 3a93755e880fee23fa6d8370916caefb21f2c9eb..0c52941dd62c0d8ccb6d16b41472d9d6ad28fe5f 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -651,7 +651,7 @@ static unsigned long randomize_stack_top(unsigned long stack_top)
 
        if ((current->flags & PF_RANDOMIZE) &&
                !(current->personality & ADDR_NO_RANDOMIZE)) {
-               random_variable = (unsigned long) get_random_int();
+               random_variable = get_random_long();
                random_variable &= STACK_RND_MASK;
                random_variable <<= PAGE_SHIFT;
        }