From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Subject: Re: [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Date: Wed, 19 Jun 2019 10:46:17 -0600 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Andrey Konovalov , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Mark Rutland , Szabolcs Nagy , Catalin Marinas , Will Deacon , Kostya Serebryany , Felix Kuehling , Vincenzo Frascino , Jacob Bramley , Leon Romanovsky , Christoph Hellwig , Jason Gunthorpe , Dave Martin , Evgeniy Stepanov , Kevin Brodsky , Kees Cook , Ruben Ayrapetyan , Ramana Radhakrishnan , Alex Williamson , Mauro Carvalho Chehab , Dmitry Vyukov , Greg Kroah-Hartman , Yishai Hadas J List-Id: dri-devel@lists.freedesktop.org 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......." -- 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)) >> > >