| Message ID | 1425341988-1599-2-git-send-email-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Mar 02, 2015 at 04:19:44PM -0800, Kees Cook wrote: > In preparation for exporting per-arch mmap randomization functions, > this moves the ASLR calculations for mmap on ARM into a separate routine. > > Signed-off-by: Kees Cook <keescook@chromium.org> Looks fine, thanks. Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> > --- > arch/arm/mm/mmap.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c > index 5e85ed371364..0f8bc158f2c6 100644 > --- a/arch/arm/mm/mmap.c > +++ b/arch/arm/mm/mmap.c > @@ -169,14 +169,21 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, > return addr; > } > > -void arch_pick_mmap_layout(struct mm_struct *mm) > +static unsigned long mmap_rnd(void) > { > - unsigned long random_factor = 0UL; > + unsigned long rnd = 0UL; > > /* 8 bits of randomness in 20 address space bits */ > if ((current->flags & PF_RANDOMIZE) && > !(current->personality & ADDR_NO_RANDOMIZE)) > - random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT; > + rnd = (get_random_int() % (1 << 8)) << PAGE_SHIFT; > + > + return rnd; > +} > + > +void arch_pick_mmap_layout(struct mm_struct *mm) > +{ > + unsigned long random_factor = mmap_rnd(); > > if (mmap_is_legacy()) { > mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; > -- > 1.9.1 >
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 5e85ed371364..0f8bc158f2c6 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -169,14 +169,21 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, return addr; } -void arch_pick_mmap_layout(struct mm_struct *mm) +static unsigned long mmap_rnd(void) { - unsigned long random_factor = 0UL; + unsigned long rnd = 0UL; /* 8 bits of randomness in 20 address space bits */ if ((current->flags & PF_RANDOMIZE) && !(current->personality & ADDR_NO_RANDOMIZE)) - random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT; + rnd = (get_random_int() % (1 << 8)) << PAGE_SHIFT; + + return rnd; +} + +void arch_pick_mmap_layout(struct mm_struct *mm) +{ + unsigned long random_factor = mmap_rnd(); if (mmap_is_legacy()) { mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
In preparation for exporting per-arch mmap randomization functions, this moves the ASLR calculations for mmap on ARM into a separate routine. Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/arm/mm/mmap.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)