From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E4DEC4649B for ; Fri, 5 Jul 2019 14:19:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C0F420856 for ; Fri, 5 Jul 2019 14:19:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725917AbfGEOTG (ORCPT ); Fri, 5 Jul 2019 10:19:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:56230 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725497AbfGEOTG (ORCPT ); Fri, 5 Jul 2019 10:19:06 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F00B220828; Fri, 5 Jul 2019 14:19:04 +0000 (UTC) Date: Fri, 5 Jul 2019 10:19:03 -0400 From: Steven Rostedt To: tz.stoyanov@gmail.com Cc: linux-trace-devel@vger.kernel.org, Yordan Karadzhov , Slavomir Kaslev Subject: Re: [PATCH v2] trace-cmd: Add option to execute traced process as given user Message-ID: <20190705101903.6b0d3406@gandalf.local.home> In-Reply-To: <20190705135331.20705-1-tz.stoyanov@gmail.com> References: <20190705135331.20705-1-tz.stoyanov@gmail.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Fri, 5 Jul 2019 16:53:31 +0300 tz.stoyanov@gmail.com wrote: > From: "Tzvetomir Stoyanov (VMware)" > > A new trace-cmd record option is added: "--user". When it is set with > combination of option -F, the traced process is executed in the context > of the specified user. > Yordan and Slavomir, Care to review this patch? > Signed-off-by: Tzvetomir Stoyanov (VMware) > Suggested-by: Yordan Karadzhov (VMware) Ceco, Note, it is better to add your Signed-of-by at the end. I know things like patchwork appear to insert everything after the Signed-off-by, and some people do it this way, but I think its best to see all the Signed-off-bys at the end, as they are the most important tags in the commit log. Some comments below. > --- > [ > Should be applied on top of patch "trace-cmd: Save the tracee memory map > into the trace.dat file." > > v2 changes: > - Check for errors in change_user(). If an error occurs while > changing the user, the message is printed and the traced > process is not executed. > ] > > Documentation/trace-cmd-record.1.txt | 4 +++ > tracecmd/trace-record.c | 47 ++++++++++++++++++++++++++-- > tracecmd/trace-usage.c | 1 + > 3 files changed, 49 insertions(+), 3 deletions(-) > > diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt > index 4a59de9..df92354 100644 > --- a/Documentation/trace-cmd-record.1.txt > +++ b/Documentation/trace-cmd-record.1.txt > @@ -122,6 +122,10 @@ OPTIONS > *--mmap*:: > Used with either *-F* or *-P*, save the traced process memory map into > the trace.dat file. > + > +*--user*:: > + Used with -F, execute the traced process as given user. Why does it have to be used with -F? I could see it this be useful for recording events other than just what is being executed. > + > *-C* 'clock':: > Set the trace clock to "clock". > > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c > index 48081d4..3a37cc2 100644 > --- a/tracecmd/trace-record.c > +++ b/tracecmd/trace-record.c > @@ -33,6 +33,8 @@ > #include > #include > #include > +#include > +#include > > #include "version.h" > #include "trace-local.h" > @@ -208,6 +210,7 @@ struct common_record_context { > struct buffer_instance *instance; > const char *output; > char *date2ts; > + char *user; > int data_flags; > > int record_all; > @@ -1417,7 +1420,34 @@ static void trace_or_sleep(enum trace_type type) > sleep(10); > } > > -static void run_cmd(enum trace_type type, int argc, char **argv) > +static int change_user(char *user) > +{ > + struct passwd *pwd; > + > + if (!user) > + return -1; I would have this return 0, and then remove the check below, as it is redundant. > + > + pwd = getpwnam(user); > + if (!pwd) > + return -1; > + if (initgroups(user, pwd->pw_gid) < 0) > + return -1; > + if (setgid(pwd->pw_gid) < 0) > + return -1; > + if (setuid(pwd->pw_uid) < 0) > + return -1; > + > + if (setenv("HOME", pwd->pw_dir, 1) < 0) > + return -1; > + if (setenv("USER", pwd->pw_name, 1) < 0) > + return -1; > + if (setenv("LOGNAME", pwd->pw_name, 1) < 0) > + return -1; > + > + return 0; > +} > + > +static void run_cmd(enum trace_type type, char *user, int argc, char **argv) > { > int status; > int pid; > @@ -1438,6 +1468,10 @@ static void run_cmd(enum trace_type type, int argc, char **argv) > dup2(save_stdout, 1); > close(save_stdout); > } > + > + if (user && change_user(user) < 0) With the change of !user return 0 above, we can make this: if (change_user(user) < 0) > + die("Failed to change user to %s", user); > + > if (execvp(argv[0], argv)) { > fprintf(stderr, "\n********************\n"); > fprintf(stderr, " Unable to exec %s\n", argv[0]); > @@ -4548,6 +4582,7 @@ void update_first_instance(struct buffer_instance *instance, int topt) > } > > enum { > + OPT_user = 243, > OPT_mmap = 244, > OPT_quiet = 245, > OPT_debug = 246, > @@ -4780,6 +4815,7 @@ static void parse_record_options(int argc, > {"quiet", no_argument, NULL, OPT_quiet}, > {"help", no_argument, NULL, '?'}, > {"mmap", no_argument, NULL, OPT_mmap}, > + {"user", required_argument, NULL, OPT_user}, > {"module", required_argument, NULL, OPT_module}, > {NULL, 0, NULL, 0} > }; > @@ -5011,6 +5047,9 @@ static void parse_record_options(int argc, > case 'i': > ignore_event_not_found = 1; > break; > + case OPT_user: > + ctx->user = strdup(optarg); > + break; > case OPT_mmap: > get_mmap = 1; > break; > @@ -5079,7 +5118,9 @@ static void parse_record_options(int argc, > if (!ctx->filtered && ctx->instance->filter_mod) > add_func(&ctx->instance->filter_funcs, > ctx->instance->filter_mod, "*"); > - > + if (ctx->user && !filter_task) > + warning("--user %s is ignored, no traced process is specified", > + ctx->user); Should change this to: if (ctx->user && !ctx->run_command) > if (filter_task && get_mmap) > do_ptrace = 1; > > @@ -5237,7 +5278,7 @@ static void record_trace(int argc, char **argv, > } > > if (ctx->run_command) > - run_cmd(type, (argc - optind) - 1, &argv[optind + 1]); > + run_cmd(type, ctx->user, (argc - optind) - 1, &argv[optind + 1]); > else { > update_task_filter(); > tracecmd_enable_tracing(); > diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c > index c658ede..fcc314e 100644 > --- a/tracecmd/trace-usage.c > +++ b/tracecmd/trace-usage.c > @@ -58,6 +58,7 @@ static struct usage_help usage_help[] = { > " --max-graph-depth limit function_graph depth\n" > " --no-filter include trace-cmd threads in the trace\n" > " --mmap used with -F or -P, save the traced process memory map into the trace.dat file\n" > + " --user used with -F, execute the traced process as given user\n" Again, let's not make it only for -F Thanks! -- Steve > }, > { > "start",