From 9cfe110d9fc0be88178770a85dc6170eecdf6be1 Mon Sep 17 00:00:00 2001 From: Sunil Nimmagadda Date: Fri, 18 Oct 2024 15:34:39 +0530 Subject: [PATCH] qemu-ga: Fix a SIGSEGV in ga_run_command() helper MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 patch rectifies the operator precedence while assigning the NUL terminator. Fixes: c3f32c13a325f1ca9a0b08c19fefe9e5cc04289d Signed-off-by: Sunil Nimmagadda Reviewed-by: Konstantin Kostiuk Reviewed-by: Daniel P. Berrangé Link: https://lore.kernel.org/r/m15xppk9qg.fsf@nimmagadda.net Signed-off-by: Konstantin Kostiuk --- qga/commands-posix.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 389c5eeb5d..636307bedf 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -84,7 +84,7 @@ 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;