From: Catalin Marinas <catalin.marinas@xxxxxxx> Subject: 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@xxxxxxx Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> Acked-by: Will Deacon <will@xxxxxxxxxx> Acked-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Cc: Szabolcs Nagy <szabolcs.nagy@xxxxxxx> Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx> Cc: Dave P Martin <Dave.Martin@xxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mmap.c | 5 +++++ mm/mremap.c | 6 +----- 2 files changed, 6 insertions(+), 5 deletions(-) --- a/mm/mmap.c~mm-untag-user-pointers-in-mmap-munmap-mremap-brk +++ a/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 l 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); } --- a/mm/mremap.c~mm-untag-user-pointers-in-mmap-munmap-mremap-brk +++ a/mm/mremap.c @@ -606,12 +606,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, a 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; _
