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Mon, 21 Oct 2024 08:26:28 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.27]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EA0BE300018D; Mon, 21 Oct 2024 08:26:21 +0000 (UTC) Date: Mon, 21 Oct 2024 09:26:18 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Sunil Nimmagadda Cc: qemu-devel@nongnu.org, michael.roth@amd.com, kkostiuk@redhat.com Subject: Re: [PATCH] qemu-ga: Fix a SIGSEGV on guest-set-time command Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.527, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1.699, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Oct 18, 2024 at 03:34:39PM +0530, Sunil Nimmagadda wrote: > qemu-ga on a NetBSD -current VM terminates with a SIGSEGV upon receiving > 'guest-set-time' command... > > Core was generated by `qemu-ga'. > Program terminated with signal SIGSEGV, Segmentation fault. > #0 0x000000000cd37a40 in ga_pipe_read_str (fd=fd@entry=0xffffff922a20, str=str@entry=0xffffff922a18) > at ../qga/commands-posix.c:88 > 88 *str[len] = '\0'; > [Current thread is 1 (process 1112)] > (gdb) bt > #0 0x000000000cd37a40 in ga_pipe_read_str (fd=fd@entry=0xffffff922a20, str=str@entry=0xffffff922a18) > at ../qga/commands-posix.c:88 > #1 0x000000000cd37b60 in ga_run_command (argv=argv@entry=0xffffff922a90, > action=action@entry=0xcda34b8 "set hardware clock to system time", errp=errp@entry=0xffffff922a70, in_str=0x0) > at ../qga/commands-posix.c:164 > #2 0x000000000cd380c4 in qmp_guest_set_time (has_time=, time_ns=, > errp=errp@entry=0xffffff922ad0) at ../qga/commands-posix.c:304 > #3 0x000000000cd253d8 in qmp_marshal_guest_set_time (args=, ret=, errp=0xffffff922b48) > at qga/qga-qapi-commands.c:193 > #4 0x000000000cd4e71c in qmp_dispatch (cmds=cmds@entry=0xcdf5b18 , request=request@entry=0xf3c711a4b000, > allow_oob=allow_oob@entry=false, cur_mon=cur_mon@entry=0x0) at ../qapi/qmp-dispatch.c:220 > #5 0x000000000cd36524 in process_event (opaque=0xf3c711a79000, obj=0xf3c711a4b000, err=0x0) at ../qga/main.c:677 > #6 0x000000000cd526f0 in json_message_process_token (lexer=lexer@entry=0xf3c711a79018, input=0xf3c712072480, > type=type@entry=JSON_RCURLY, x=28, y=1) at ../qobject/json-streamer.c:99 > #7 0x000000000cd93860 in json_lexer_feed_char (lexer=lexer@entry=0xf3c711a79018, ch=125 '}', flush=flush@entry=false) > at ../qobject/json-lexer.c:313 > #8 0x000000000cd93a00 in json_lexer_feed (lexer=lexer@entry=0xf3c711a79018, > buffer=buffer@entry=0xffffff922d10 "{\"execute\":\"guest-set-time\"}\n", size=) > at ../qobject/json-lexer.c:350 > #9 0x000000000cd5290c in json_message_parser_feed (parser=parser@entry=0xf3c711a79000, > buffer=buffer@entry=0xffffff922d10 "{\"execute\":\"guest-set-time\"}\n", size=) > at ../qobject/json-streamer.c:121 > #10 0x000000000cd361fc in channel_event_cb (condition=, data=0xf3c711a79000) at ../qga/main.c:703 > #11 0x000000000cd3710c in ga_channel_client_event (channel=, condition=, data=0xf3c711b2d300) > at ../qga/channel-posix.c:94 > #12 0x0000f3c7120d9bec in g_main_dispatch () from /usr/pkg/lib/libglib-2.0.so.0 > #13 0x0000f3c7120dd25c in g_main_context_iterate_unlocked.constprop () from /usr/pkg/lib/libglib-2.0.so.0 > #14 0x0000f3c7120ddbf0 in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0 > #15 0x000000000cda00d8 in run_agent_once (s=0xf3c711a79000) at ../qga/main.c:1522 > #16 run_agent (s=0xf3c711a79000) at ../qga/main.c:1559 > #17 main (argc=, argv=) at ../qga/main.c:1671 > (gdb) > > The commandline options used on the host machine... > qemu-system-aarch64 \ > -machine type=virt,pflash0=rom \ > -m 8G \ > -cpu host \ > -smp 8 \ > -accel hvf \ > -device virtio-net-pci,netdev=unet \ > -device virtio-blk-pci,drive=hd \ > -drive file=netbsd.qcow2,if=none,id=hd \ > -netdev user,id=unet,hostfwd=tcp::2223-:22 \ > -object rng-random,filename=/dev/urandom,id=viornd0 \ > -device virtio-rng-pci,rng=viornd0 \ > -serial mon:stdio \ > -display none \ > -blockdev node-name=rom,driver=file,filename=/opt/homebrew/Cellar/qemu/9.0.2/share/qemu/edk2-aarch64-code.fd,read-only=true \ > -chardev socket,path=/tmp/qga_netbsd.sock,server=on,wait=off,id=qga0 \ > -device virtio-serial \ > -device virtconsole,chardev=qga0,name=org.qemu.guest_agent.0 This bug isn't platform specific AFAICT, and will also hit other commands. Was introduced by: commit c3f32c13a325f1ca9a0b08c19fefe9e5cc04289d Author: Andrey Drobyshev Date: Wed Mar 20 18:16:43 2024 +0200 qga: introduce ga_run_command() helper for guest cmd execution and then affects multiple commands: qga/commands-posix: qmp_guest_set_user_password: use ga_run_command helper qga/commands-posix: execute_fsfreeze_hook: use ga_run_command helper qga/commands-posix: qmp_guest_set_time: use ga_run_command helper qga/commands-posix: qmp_guest_shutdown: use ga_run_command helper IOW, this is a regression in the 9.1.0 release > > This patch rectifies the operator precedence while assigning the NUL > terminator. > > Signed-off-by: Sunil Nimmagadda > > diff --git a/qga/commands-posix.c b/qga/commands-posix.c > index c2bd0b4..bb41fa9 100644 > --- a/qga/commands-posix.c > +++ b/qga/commands-posix.c > @@ -85,7 +85,7 @@ static ssize_t ga_pipe_read_str(int fd[2], char **str) > *str = g_realloc(*str, len + n + 1); > memcpy(*str + len, buf, n); > len += n; > - *str[len] = '\0'; > + (*str)[len] = '\0'; > } > close(fd[0]); > fd[0] = -1; Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|