mm: ASLR: use get_random_long()

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.

Signed-off-by: Daniel Cashman <dcashman@android.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: David S. Miller <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nick Kralevich <nnk@google.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Mark Salyzyn <salyzyn@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index 4b4058d..66353ca 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 4c893b5..232f787 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 5c81fdd..3530376 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 dccc87e..3c5736e 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1768,9 +1768,9 @@ 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 0f0502e..4087705 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 c690c8e..b489e97 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 96bd1e2..72bb52f 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 051ea48..7d914c6 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -653,7 +653,7 @@ 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;
        }