From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57784) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1frkJW-0002cn-Fs for qemu-devel@nongnu.org; Mon, 20 Aug 2018 09:33:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1frk9H-0004Ga-3C for qemu-devel@nongnu.org; Mon, 20 Aug 2018 09:23:15 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:54716) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1frk9G-0004G6-T9 for qemu-devel@nongnu.org; Mon, 20 Aug 2018 09:23:11 -0400 Received: by mail-wm0-f65.google.com with SMTP id c14-v6so14299093wmb.4 for ; Mon, 20 Aug 2018 06:23:10 -0700 (PDT) References: <20180818025653.21192-1-f4bug@amsat.org> From: Paolo Bonzini Message-ID: <66dfe354-9c2c-8642-a905-03155555fe99@redhat.com> Date: Mon, 20 Aug 2018 15:23:05 +0200 MIME-Version: 1.0 In-Reply-To: <20180818025653.21192-1-f4bug@amsat.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH] migration: Replace strncpy() by g_strlcpy() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , Juan Quintela , "Dr. David Alan Gilbert" , David Hildenbrand , Howard Spoelstra Cc: qemu-trivial@nongnu.org, qemu-devel@nongnu.org On 18/08/2018 04:56, Philippe Mathieu-Daudé wrote: > Fedora 29 comes with GCC 8.1 which added the 'stringop-truncation' checks. > > Replace the strncpy() calls by g_strlcpy() to avoid the following warning: > > migration/global_state.c: In function 'global_state_store_running': > migration/global_state.c:45:5: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation] > strncpy((char *)global_state.runstate, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > state, sizeof(global_state.runstate)); > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Reported-by: Howard Spoelstra > Signed-off-by: Philippe Mathieu-Daudé > --- > See http://lists.nongnu.org/archive/html/qemu-devel/2018-07/msg03723.html > > migration/global_state.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/migration/global_state.c b/migration/global_state.c > index 8e8ab5c51e..d5df502cd5 100644 > --- a/migration/global_state.c > +++ b/migration/global_state.c > @@ -42,7 +42,7 @@ int global_state_store(void) > void global_state_store_running(void) > { > const char *state = RunState_str(RUN_STATE_RUNNING); > - strncpy((char *)global_state.runstate, > + g_strlcpy((char *)global_state.runstate, > state, sizeof(global_state.runstate)); > } > > This is wrong because strlcpy doesn't zero the rest of global_state.runstate, so you could end up with something like "running\0ate\0\0..." in global_state.runstate However, the same mistake is already present in vl.c's runstate_store. Juan, David, what to do? strncpy is easy to misuse, but we do have cases where it's correct and it should tingle the reviewers' spidey senses... I wouldn't mind disabling the warning, and using strncpy in runstate_store, because in practice it's already reported by Coverity and it can be shut up there. Thanks, Paolo