From 057d3389108eda8a20c7f496f011846932680d88 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Wed, 25 Sep 2019 16:48:30 -0700 Subject: mm: untag user pointers passed to memory syscalls 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 --- mm/msync.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'mm/msync.c') 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)) -- cgit v1.2.3-58-ga151