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Commit ce18d171 authored by Catalin Marinas's avatar Catalin Marinas Committed by Linus Torvalds
Browse files

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: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarWill Deacon <will@kernel.org>
Acked-by: default avatarAndrey 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6cf5354c

mm/mmap.c

+5 −0
Original line number Diff line number Diff line
@@ -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);

}

mm/mremap.c

+1 −5
Original line number Diff line number Diff line
@@ -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;