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vmspawn: correctly escape ',' in certain values passed to qemu

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This commit is contained in:
Sam Leonard
2024-02-21 10:22:40 +00:00
parent 3c6d9d1c39
commit 018cc9eaf6
5 changed files with 117 additions and 11 deletions
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src/vmspawn/meson.build
+9 -1
View File
@@ -18,6 +18,10 @@ vmspawn_libs = [
libshared,
]
vmspawn_test_template = test_template + {
'link_with' : [vmspawn_libs],
}
executables += [
executable_template + {
'name' : 'systemd-vmspawn',
@@ -26,5 +30,9 @@ executables += [
'sources' : files('vmspawn.c'),
'link_with' : vmspawn_libs,
'dependencies' : [libblkid]
}
},
vmspawn_test_template + {
'conditions': ['ENABLE_VMSPAWN'],
'sources' : files('test-vmspawn-util.c'),
},
]
src/vmspawn/test-vmspawn-util.c
+28
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@@ -0,0 +1,28 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <stdbool.h>
#include "alloc-util.h"
#include "string-util.h"
#include "vmspawn-util.h"
#include "tests.h"
#define _ESCAPE_QEMU_VALUE_CHECK(str, correct, varname) \
do { \
_cleanup_free_ char* varname = NULL; \
varname = escape_qemu_value(str); \
assert(varname); \
assert_se(streq(varname, correct)); \
} while (0)
#define ESCAPE_QEMU_VALUE_CHECK(str, correct) \
_ESCAPE_QEMU_VALUE_CHECK(str, correct, conf##__COUNTER__)
TEST(escape_qemu_value) {
ESCAPE_QEMU_VALUE_CHECK("abcde", "abcde");
ESCAPE_QEMU_VALUE_CHECK("a,bcde", "a,,bcde");
ESCAPE_QEMU_VALUE_CHECK(",,,", ",,,,,,");
ESCAPE_QEMU_VALUE_CHECK("", "");
}
DEFINE_TEST_MAIN(LOG_INFO);
src/vmspawn/vmspawn-util.c
+34
View File
@@ -7,6 +7,7 @@
#include "architecture.h"
#include "conf-files.h"
#include "errno-util.h"
#include "escape.h"
#include "fd-util.h"
#include "fileio.h"
#include "json.h"
@@ -433,3 +434,36 @@ int vsock_fix_child_cid(int vhost_device_fd, unsigned *machine_cid, const char *
return log_debug_errno(SYNTHETIC_ERRNO(EADDRNOTAVAIL), "Failed to assign a CID to the guest vsock");
}
char* escape_qemu_value(const char *s) {
const char *f;
char *e, *t;
size_t n;
assert(s);
/* QEMU requires that commas in arguments be escaped by doubling up the commas.
* See https://www.qemu.org/docs/master/system/qemu-manpage.html#options
* for more information.
*
* This function performs this escaping, returning an allocated string with the escaped value, or NULL if allocation failed. */
n = strlen(s);
if (n > (SIZE_MAX - 1) / 2)
return NULL;
e = new(char, n*2 + 1);
if (!e)
return NULL;
for (f = s, t = e; f < s + n; f++) {
*t++ = *f;
if (*f == ',')
*t++ = ',';
}
*t = 0;
return e;
}
src/vmspawn/vmspawn-util.h
+2
View File
@@ -87,3 +87,5 @@ int load_ovmf_config(const char *path, OvmfConfig **ret);
int find_ovmf_config(int search_sb, OvmfConfig **ret);
int find_qemu_binary(char **ret_qemu_binary);
int vsock_fix_child_cid(int vsock_fd, unsigned *machine_cid, const char *machine);
char* escape_qemu_value(const char *s);
src/vmspawn/vmspawn.c
+44 -10
View File
@@ -1207,13 +1207,18 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
if (r < 0)
return log_oom();
r = strv_extendf(&cmdline, "if=pflash,format=%s,readonly=on,file=%s", ovmf_config_format(ovmf_config), ovmf_config->path);
_cleanup_free_ char *escaped_ovmf_config_path = escape_qemu_value(ovmf_config->path);
if (!escaped_ovmf_config_path)
return log_oom();
r = strv_extendf(&cmdline, "if=pflash,format=%s,readonly=on,file=%s", ovmf_config_format(ovmf_config), escaped_ovmf_config_path);
if (r < 0)
return log_oom();
_cleanup_(unlink_and_freep) char *ovmf_vars_to = NULL;
if (ovmf_config->supports_sb) {
const char *ovmf_vars_from = ovmf_config->vars;
_cleanup_free_ char *escaped_ovmf_vars_to = NULL;
_cleanup_close_ int source_fd = -EBADF, target_fd = -EBADF;
r = tempfn_random_child(NULL, "vmspawn-", &ovmf_vars_to);
@@ -1245,7 +1250,11 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
if (r < 0)
return log_oom();
r = strv_extendf(&cmdline, "file=%s,if=pflash,format=%s", ovmf_vars_to, ovmf_config_format(ovmf_config));
escaped_ovmf_vars_to = escape_qemu_value(ovmf_vars_to);
if (!escaped_ovmf_vars_to)
return log_oom();
r = strv_extendf(&cmdline, "file=%s,if=pflash,format=%s", escaped_ovmf_vars_to, ovmf_config_format(ovmf_config));
if (r < 0)
return log_oom();
}
@@ -1265,13 +1274,19 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
}
if (arg_image) {
_cleanup_free_ char *escaped_image = NULL;
assert(!arg_directory);
r = strv_extend(&cmdline, "-drive");
if (r < 0)
return log_oom();
r = strv_extendf(&cmdline, "if=none,id=mkosi,file=%s,format=raw", arg_image);
escaped_image = escape_qemu_value(arg_image);
if (!escaped_image)
log_oom();
r = strv_extendf(&cmdline, "if=none,id=mkosi,file=%s,format=raw", escaped_image);
if (r < 0)
return log_oom();
@@ -1283,16 +1298,21 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
}
if (arg_directory) {
_cleanup_free_ char *sock_path = NULL, *sock_name = NULL;
_cleanup_free_ char *sock_path = NULL, *sock_name = NULL, *escaped_sock_path = NULL;
r = start_virtiofsd(bus, trans_scope, arg_directory, /* uidmap= */ true, &sock_path, &sock_name);
if (r < 0)
return r;
escaped_sock_path = escape_qemu_value(sock_path);
if (!escaped_sock_path)
log_oom();
r = strv_extend(&cmdline, "-chardev");
if (r < 0)
return log_oom();
r = strv_extendf(&cmdline, "socket,id=%1$s,path=%2$s/%1$s", sock_name, sock_path);
r = strv_extendf(&cmdline, "socket,id=%1$s,path=%2$s/%1$s", sock_name, escaped_sock_path);
if (r < 0)
return log_oom();
@@ -1314,16 +1334,20 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
return log_oom();
FOREACH_ARRAY(mount, arg_runtime_mounts.mounts, arg_runtime_mounts.n_mounts) {
_cleanup_free_ char *sock_path = NULL, *sock_name = NULL, *clean_target = NULL;
_cleanup_free_ char *sock_path = NULL, *sock_name = NULL, *clean_target = NULL, *escaped_sock_path = NULL;
r = start_virtiofsd(bus, trans_scope, mount->source, /* uidmap= */ false, &sock_path, &sock_name);
if (r < 0)
return r;
escaped_sock_path = escape_qemu_value(sock_path);
if (!escaped_sock_path)
log_oom();
r = strv_extend(&cmdline, "-chardev");
if (r < 0)
return log_oom();
r = strv_extendf(&cmdline, "socket,id=%1$s,path=%2$s/%1$s", sock_name, sock_path);
r = strv_extendf(&cmdline, "socket,id=%1$s,path=%2$s/%1$s", sock_name, escaped_sock_path);
if (r < 0)
return log_oom();
@@ -1346,7 +1370,7 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
}
if (ARCHITECTURE_SUPPORTS_SMBIOS) {
_cleanup_free_ char *kcl = strv_join(arg_kernel_cmdline_extra, " ");
_cleanup_free_ char *kcl = strv_join(arg_kernel_cmdline_extra, " "), *escaped_kcl = NULL;
if (!kcl)
return log_oom();
@@ -1356,11 +1380,15 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
return log_oom();
} else {
if (ARCHITECTURE_SUPPORTS_SMBIOS) {
escaped_kcl = escape_qemu_value(kcl);
if (!escaped_kcl)
log_oom();
r = strv_extend(&cmdline, "-smbios");
if (r < 0)
return log_oom();
r = strv_extendf(&cmdline, "type=11,value=io.systemd.stub.kernel-cmdline-extra=%s", kcl);
r = strv_extendf(&cmdline, "type=11,value=io.systemd.stub.kernel-cmdline-extra=%s", escaped_kcl);
if (r < 0)
return log_oom();
} else
@@ -1393,6 +1421,8 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
_cleanup_free_ const char *tpm_state_tempdir = NULL;
if (swtpm) {
_cleanup_free_ char *escaped_state_dir = NULL;
r = start_tpm(bus, trans_scope, swtpm, &tpm_state_tempdir);
if (r < 0) {
/* only bail if the user asked for a tpm */
@@ -1401,11 +1431,15 @@ static int run_virtual_machine(int kvm_device_fd, int vhost_device_fd) {
log_debug_errno(r, "Failed to start tpm, ignoring: %m");
}
escaped_state_dir = escape_qemu_value(tpm_state_tempdir);
if (!escaped_state_dir)
log_oom();
r = strv_extend(&cmdline, "-chardev");
if (r < 0)
return log_oom();
r = strv_extendf(&cmdline, "socket,id=chrtpm,path=%s/sock", tpm_state_tempdir);
r = strv_extendf(&cmdline, "socket,id=chrtpm,path=%s/sock", escaped_state_dir);
if (r < 0)
return log_oom();