From 1eb40df35d99f353e7bdfcbb21f249428ec0f4b6 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 22 Aug 2016 16:41:46 -0700 Subject: [PATCH] binfmt_elf: switch to new creds when switching to new mm MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 9f834ec18defc369d73ccf9e87a2790bfa05bf46 upstream. We used to delay switching to the new credentials until after we had mapped the executable (and possible elf interpreter). That was kind of odd to begin with, since the new executable will actually then _run_ with the new creds, but whatever. The bigger problem was that we also want to make sure that we turn off prof events and tracing before we start mapping the new executable state. So while this is a cleanup, it's also a fix for a possible information leak. Reported-by: Robert Święcki Tested-by: Peter Zijlstra Acked-by: David Howells Acked-by: Oleg Nesterov Acked-by: Andy Lutomirski Acked-by: Eric W. Biederman Cc: Willy Tarreau Cc: Kees Cook Cc: Al Viro Signed-off-by: Linus Torvalds Cc: Federico Manuel Bento Signed-off-by: Greg Kroah-Hartman --- fs/binfmt_elf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index f010d6c8dd14..f1f32e55d877 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -850,6 +850,7 @@ static int load_elf_binary(struct linux_binprm *bprm) current->flags |= PF_RANDOMIZE; setup_new_exec(bprm); + install_exec_creds(bprm); /* Do this so that we can load the interpreter, if need be. We will change some of these later */ @@ -1084,7 +1085,6 @@ static int load_elf_binary(struct linux_binprm *bprm) goto out; #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */ - install_exec_creds(bprm); retval = create_elf_tables(bprm, &loc->elf_ex, load_addr, interp_load_addr); if (retval < 0)