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=<optimized out>, time_ns=<optimized out>,
errp=errp@entry=0xffffff922ad0) at ../qga/commands-posix.c:304
#3 0x000000000cd253d8 in qmp_marshal_guest_set_time (args=<optimized out>, ret=<optimized out>, errp=0xffffff922b48)
at qga/qga-qapi-commands.c:193
#4 0x000000000cd4e71c in qmp_dispatch (cmds=cmds@entry=0xcdf5b18 <ga_commands>, 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=<optimized out>)
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=<optimized out>)
at ../qobject/json-streamer.c:121
#10 0x000000000cd361fc in channel_event_cb (condition=<optimized out>, data=0xf3c711a79000) at ../qga/main.c:703
#11 0x000000000cd3710c in ga_channel_client_event (channel=<optimized out>, condition=<optimized out>, 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=<optimized out>, argv=<optimized out>) 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.
Signed-off-by: Sunil Nimmagadda <sunil@nimmagadda.net>
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;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=<optimized out>, time_ns=<optimized out>,
> errp=errp@entry=0xffffff922ad0) at ../qga/commands-posix.c:304
> #3 0x000000000cd253d8 in qmp_marshal_guest_set_time (args=<optimized out>, ret=<optimized out>, errp=0xffffff922b48)
> at qga/qga-qapi-commands.c:193
> #4 0x000000000cd4e71c in qmp_dispatch (cmds=cmds@entry=0xcdf5b18 <ga_commands>, 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=<optimized out>)
> 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=<optimized out>)
> at ../qobject/json-streamer.c:121
> #10 0x000000000cd361fc in channel_event_cb (condition=<optimized out>, data=0xf3c711a79000) at ../qga/main.c:703
> #11 0x000000000cd3710c in ga_channel_client_event (channel=<optimized out>, condition=<optimized out>, 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=<optimized out>, argv=<optimized out>) 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 <andrey.drobyshev@virtuozzo.com>
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 <sunil@nimmagadda.net>
>
> 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 <berrange@redhat.com>
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 :|
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
On Fri, Oct 18, 2024 at 1:14 PM Sunil Nimmagadda <sunil@nimmagadda.net>
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=<optimized out>,
> time_ns=<optimized out>,
> errp=errp@entry=0xffffff922ad0) at ../qga/commands-posix.c:304
> #3 0x000000000cd253d8 in qmp_marshal_guest_set_time (args=<optimized
> out>, ret=<optimized out>, errp=0xffffff922b48)
> at qga/qga-qapi-commands.c:193
> #4 0x000000000cd4e71c in qmp_dispatch (cmds=cmds@entry=0xcdf5b18
> <ga_commands>, 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=<optimized out>)
> 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=<optimized out>)
> at ../qobject/json-streamer.c:121
> #10 0x000000000cd361fc in channel_event_cb (condition=<optimized out>,
> data=0xf3c711a79000) at ../qga/main.c:703
> #11 0x000000000cd3710c in ga_channel_client_event (channel=<optimized
> out>, condition=<optimized out>, 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=<optimized out>, argv=<optimized out>) 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.
>
> Signed-off-by: Sunil Nimmagadda <sunil@nimmagadda.net>
>
> 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;
>
>
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