On 12/06/2019 12:43, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > This patch allows tagged pointers to be passed to the following memory > syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect, > mremap, msync, munlock, move_pages. > > The mmap and mremap syscalls do not currently accept tagged addresses. > Architectures may interpret the tag as a background colour for the > corresponding vma. > > Reviewed-by: Catalin Marinas <catalin.mari...@arm.com> > Reviewed-by: Kees Cook <keesc...@chromium.org> > Signed-off-by: Andrey Konovalov <andreyk...@google.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frasc...@arm.com> > --- > mm/madvise.c | 2 ++ > mm/mempolicy.c | 3 +++ > mm/migrate.c | 2 +- > mm/mincore.c | 2 ++ > mm/mlock.c | 4 ++++ > mm/mprotect.c | 2 ++ > mm/mremap.c | 7 +++++++ > mm/msync.c | 2 ++ > 8 files changed, 23 insertions(+), 1 deletion(-) > > diff --git a/mm/madvise.c b/mm/madvise.c > index 628022e674a7..39b82f8a698f 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -810,6 +810,8 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, > len_in, int, behavior) > size_t len; > struct blk_plug plug; > > + start = untagged_addr(start); > + > if (!madvise_behavior_valid(behavior)) > return error; > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index 01600d80ae01..78e0a88b2680 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1360,6 +1360,7 @@ static long kernel_mbind(unsigned long start, unsigned > long len, > int err; > unsigned short mode_flags; > > + start = untagged_addr(start); > mode_flags = mode & MPOL_MODE_FLAGS; > mode &= ~MPOL_MODE_FLAGS; > if (mode >= MPOL_MAX) > @@ -1517,6 +1518,8 @@ static int kernel_get_mempolicy(int __user *policy, > int uninitialized_var(pval); > nodemask_t nodes; > > + addr = untagged_addr(addr); > + > if (nmask != NULL && maxnode < nr_node_ids) > return -EINVAL; > > diff --git a/mm/migrate.c b/mm/migrate.c > index f2ecc2855a12..d22c45cf36b2 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1616,7 +1616,7 @@ static int do_pages_move(struct mm_struct *mm, > nodemask_t task_nodes, > goto out_flush; > if (get_user(node, nodes + i)) > goto out_flush; > - addr = (unsigned long)p; > + addr = (unsigned long)untagged_addr(p); > > err = -ENODEV; > if (node < 0 || node >= MAX_NUMNODES) > diff --git a/mm/mincore.c b/mm/mincore.c > index c3f058bd0faf..64c322ed845c 100644 > --- a/mm/mincore.c > +++ b/mm/mincore.c > @@ -249,6 +249,8 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, > len, > unsigned long pages; > unsigned char *tmp; > > + start = untagged_addr(start); > + > /* Check the start address: needs to be page-aligned.. */ > if (start & ~PAGE_MASK) > return -EINVAL; > diff --git a/mm/mlock.c b/mm/mlock.c > index 080f3b36415b..e82609eaa428 100644 > --- a/mm/mlock.c > +++ b/mm/mlock.c > @@ -674,6 +674,8 @@ static __must_check int do_mlock(unsigned long start, > size_t len, vm_flags_t fla > unsigned long lock_limit; > int error = -ENOMEM; > > + start = untagged_addr(start); > + > if (!can_do_mlock()) > return -EPERM; > > @@ -735,6 +737,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, > len) > { > int ret; > > + start = untagged_addr(start); > + > len = PAGE_ALIGN(len + (offset_in_page(start))); > start &= PAGE_MASK; > > diff --git a/mm/mprotect.c b/mm/mprotect.c > index bf38dfbbb4b4..19f981b733bc 100644 > --- a/mm/mprotect.c > +++ b/mm/mprotect.c > @@ -465,6 +465,8 @@ static int do_mprotect_pkey(unsigned long start, size_t > len, > const bool rier = (current->personality & READ_IMPLIES_EXEC) && > (prot & PROT_READ); > > + start = untagged_addr(start); > + > prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); > if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ > return -EINVAL; > diff --git a/mm/mremap.c b/mm/mremap.c > index fc241d23cd97..64c9a3b8be0a 100644 > --- a/mm/mremap.c > +++ b/mm/mremap.c > @@ -606,6 +606,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned > long, old_len, > LIST_HEAD(uf_unmap_early); > LIST_HEAD(uf_unmap); > > + /* > + * Architectures may interpret the tag passed to mmap as a background > + * colour for the corresponding vma. For mremap we don't allow tagged > + * new_addr to preserve similar behaviour to mmap. > + */ > + addr = untagged_addr(addr); > + > if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE)) > return ret; > > diff --git a/mm/msync.c b/mm/msync.c > index ef30a429623a..c3bd3e75f687 100644 > --- a/mm/msync.c > +++ b/mm/msync.c > @@ -37,6 +37,8 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, > int, flags) > int unmapped_error = 0; > int error = -EINVAL; > > + start = untagged_addr(start); > + > if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) > goto out; > if (offset_in_page(start)) > -- Regards, Vincenzo