@@ -15,7 +15,9 @@
#ifndef QEMU_SECCOMP_H
#define QEMU_SECCOMP_H
+#define OBSOLETE 0x0001
+
#include <seccomp.h>
-int seccomp_start(void);
+int seccomp_start(uint8_t seccomp_opts);
#endif
@@ -4004,13 +4004,18 @@ Old param mode (ARM only).
ETEXI
DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
- "-sandbox <arg> Enable seccomp mode 2 system call filter (default 'off').\n",
+ "-sandbox on[,obsolete=allow] Enable seccomp mode 2 system call filter (default 'off').\n" \
+ " obsolete: Allow obsolete system calls\n",
QEMU_ARCH_ALL)
STEXI
-@item -sandbox @var{arg}
+@item -sandbox @var{arg}[,obsolete=@var{string}]
@findex -sandbox
Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering and 'off' will
disable it. The default is 'off'.
+@table @option
+@item obsolete=@var{string}
+Enable Obsolete system calls
+@end table
ETEXI
DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
@@ -31,6 +31,20 @@ struct QemuSeccompSyscall {
uint8_t priority;
};
+static const struct QemuSeccompSyscall obsolete[] = {
+ { SCMP_SYS(readdir), 255 },
+ { SCMP_SYS(_sysctl), 255 },
+ { SCMP_SYS(bdflush), 255 },
+ { SCMP_SYS(create_module), 255 },
+ { SCMP_SYS(get_kernel_syms), 255 },
+ { SCMP_SYS(query_module), 255 },
+ { SCMP_SYS(sgetmask), 255 },
+ { SCMP_SYS(ssetmask), 255 },
+ { SCMP_SYS(sysfs), 255 },
+ { SCMP_SYS(uselib), 255 },
+ { SCMP_SYS(ustat), 255 },
+};
+
static const struct QemuSeccompSyscall blacklist[] = {
{ SCMP_SYS(reboot), 255 },
{ SCMP_SYS(swapon), 255 },
@@ -56,7 +70,20 @@ static const struct QemuSeccompSyscall blacklist[] = {
{ SCMP_SYS(vserver), 255 },
};
-int seccomp_start(void)
+static int is_obsolete(int syscall)
+{
+ unsigned int i = 0;
+
+ for (i = 0; i < ARRAY_SIZE(obsolete); i++) {
+ if (syscall == obsolete[i].num) {
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+int seccomp_start(uint8_t seccomp_opts)
{
int rc = 0;
unsigned int i = 0;
@@ -69,6 +96,9 @@ int seccomp_start(void)
}
for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
+ if ((seccomp_opts & OBSOLETE) && is_obsolete(blacklist[i].num)) {
+ continue;
+ }
rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
if (rc < 0) {
goto seccomp_return;
@@ -271,6 +271,10 @@ static QemuOptsList qemu_sandbox_opts = {
.name = "enable",
.type = QEMU_OPT_BOOL,
},
+ {
+ .name = "obsolete",
+ .type = QEMU_OPT_STRING,
+ },
{ /* end of list */ }
},
};
@@ -1032,7 +1036,17 @@ static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
{
if (qemu_opt_get_bool(opts, "enable", false)) {
#ifdef CONFIG_SECCOMP
- if (seccomp_start() < 0) {
+ uint8_t seccomp_opts = 0x0000;
+ const char *value = NULL;
+
+ value = qemu_opt_get(opts, "obsolete");
+ if (value) {
+ if (strcmp(value, "allow") == 0) {
+ seccomp_opts |= OBSOLETE;
+ }
+ }
+
+ if (seccomp_start(seccomp_opts) < 0) {
error_report("failed to install seccomp syscall filter "
"in the kernel");
return -1;
This patch introduces the argument [,obsolete=allow] to the `-sandbox on' option. It allows Qemu to run safely on old system that still relies on old system calls. Signed-off-by: Eduardo Otubo <otubo@redhat.com> --- include/sysemu/seccomp.h | 4 +++- qemu-options.hx | 9 +++++++-- qemu-seccomp.c | 32 +++++++++++++++++++++++++++++++- vl.c | 16 +++++++++++++++- 4 files changed, 56 insertions(+), 5 deletions(-)