From 38dc5079da7081e8b09b14e255e9da82c451a531 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 26 Oct 2020 18:03:18 -0600 Subject: Fix compat regression in process_vm_rw() The removal of compat_process_vm_{readv,writev} didn't change process_vm_rw(), which always assumes it's not doing a compat syscall. Instead of passing in 'false' unconditionally for 'compat', make it conditional on in_compat_syscall(). [ Both Al and Christoph point out that trying to access a 64-bit process from a 32-bit one cannot work anyway, and is likely better prohibited, but that's a separate issue - Linus ] Fixes: c3973b401ef2 ("mm: remove compat_process_vm_{readv,writev}") Reported-and-tested-by: Kyle Huey Signed-off-by: Jens Axboe Acked-by: Al Viro Reviewed-by: Christoph Hellwig Signed-off-by: Linus Torvalds --- mm/process_vm_access.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm/process_vm_access.c') diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index fd12da80b6f2..05676722d9cd 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -273,7 +273,8 @@ static ssize_t process_vm_rw(pid_t pid, return rc; if (!iov_iter_count(&iter)) goto free_iov_l; - iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, false); + iov_r = iovec_from_user(rvec, riovcnt, UIO_FASTIOV, iovstack_r, + in_compat_syscall()); if (IS_ERR(iov_r)) { rc = PTR_ERR(iov_r); goto free_iov_l; -- cgit v1.2.3-70-g09d2