From 690c4ca8a5715644370384672f24d95b042db74a Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Wed, 25 Sep 2019 16:48:30 -0700 Subject: [PATCH] UPSTREAM: mm: untag user pointers passed to memory syscalls (Upstream commit 057d3389108eda8a20c7f496f011846932680d88). This patch is a part of a series that extends 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. Link: http://lkml.kernel.org/r/aaf0c0969d46b2feb9017f3e1b3ef3970b633d91.1563904656.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Khalid Aziz Reviewed-by: Vincenzo Frascino Reviewed-by: Catalin Marinas Reviewed-by: Kees Cook Cc: Al Viro Cc: Dave Hansen Cc: Eric Auger Cc: Felix Kuehling Cc: Jens Wiklander Cc: Mauro Carvalho Chehab Cc: Mike Rapoport Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Andrey Konovalov Bug: 135692346 Change-Id: I1a2d89eedb45e618e85ca515f4c9121460711efb --- 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 899b19e38aee..68a9626ef8f2 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -808,6 +808,8 @@ 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 47536fab96d5..396c6ba3fcf6 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1393,6 +1393,7 @@ 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) @@ -1550,6 +1551,8 @@ 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 8d05078390b0..9cee9479c039 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1606,7 +1606,7 @@ 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 2732c8c0764c..7eb149191550 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 02d8a89cf49b..ef2abafbc18f 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 58f591daf578..cb1899568474 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -463,6 +463,8 @@ 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 a9617e72e6b7..1b5baa7b9a64 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -525,6 +525,13 @@ 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))