mm: untag user pointers in mmap/munmap/mremap/brk

There isn't a good reason to differentiate between the user address space
layout modification syscalls and the other memory permission/attributes
ones (e.g.  mprotect, madvise) w.r.t.  the tagged address ABI.  Untag the
user addresses on entry to these functions.

Link: http://lkml.kernel.org/r/20190821164730.47450-2-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Dave P Martin <Dave.Martin@arm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index 14b7da317ec044500fe9e8c33c0758ecc6b9c575..a7d8c84d19b7127aef8680ac0dd7cbca0e03041f 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -201,6 +201,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
        bool downgraded = false;
        LIST_HEAD(uf);
 
+       brk = untagged_addr(brk);
+
        if (down_write_killable(&mm->mmap_sem))
                return -EINTR;
 
@@ -1587,6 +1589,8 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
        struct file *file = NULL;
        unsigned long retval;
 
+       addr = untagged_addr(addr);
+
        if (!(flags & MAP_ANONYMOUS)) {
                audit_mmap_fd(fd, flags);
                file = fget(fd);
@@ -2885,6 +2889,7 @@ EXPORT_SYMBOL(vm_munmap);
 
 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
 {
+       addr = untagged_addr(addr);
        profile_munmap(addr);
        return __vm_munmap(addr, len, true);
 }

diff --git a/mm/mremap.c b/mm/mremap.c
index 64c9a3b8be0aa2c8f5b1472b8cbb21f20b1c754f..1fc8a29fbe3f44a7ecbee35eb67cbebc815f78ad 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -606,12 +606,8 @@ 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);
+       new_addr = untagged_addr(new_addr);
 
        if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
                return ret;