From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrey Konovalov Subject: Re: [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Date: Mon, 24 Jun 2019 16:22:34 +0200 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Khalid Aziz Cc: Linux ARM , Linux Memory Management List , LKML , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK" , Catalin Marinas , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Kees Cook , Yishai Hadas , Felix Kuehling , Alexander Deucher List-Id: dri-devel@lists.freedesktop.org On Wed, Jun 19, 2019 at 6:46 PM Khalid Aziz wrote: > > On 6/19/19 9:55 AM, Khalid Aziz wrote: > > On 6/12/19 5:43 AM, 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 > >> Reviewed-by: Kees Cook > >> Signed-off-by: Andrey Konovalov > >> --- > > > > Reviewed-by: Khalid Aziz > > > > > > I would also recommend updating commit log for all the patches in this > series that are changing files under mm/ as opposed to arch/arm64 to not > reference arm64 kernel ABI since the change applies to every > architecture. So something along the lines of "This patch is part of a > series that extends kernel ABI to allow......." Sure, will do in v18, thanks! > > -- > Khalid > > > >> 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;fixup_user_fault > >> 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)) > >> > > > > > >