mm: untag user pointers in mmap/munmap/mremap/brk (ce18d171) · Commits · 戴 / test

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>

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;

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