seccomp: report more useful errors from seccomp

Most of the seccomp functions return errnos as a negative return
value. The code is currently ignoring these and reporting a generic
error message for all seccomp failure scenarios making debugging
painful. Report a more precise error from each failed call and include
errno if it is available.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Eduardo Otubo <otubo@redhat.com>
This commit is contained in:
Daniel P. Berrangé 2019-03-27 10:47:28 +01:00 committed by Eduardo Otubo
parent 9a1565a03b
commit 035121d23a

View file

@ -155,20 +155,22 @@ static uint32_t qemu_seccomp_get_action(int set)
}
static int seccomp_start(uint32_t seccomp_opts)
static int seccomp_start(uint32_t seccomp_opts, Error **errp)
{
int rc = 0;
int rc = -1;
unsigned int i = 0;
scmp_filter_ctx ctx;
ctx = seccomp_init(SCMP_ACT_ALLOW);
if (ctx == NULL) {
rc = -1;
error_setg(errp, "failed to initialize seccomp context");
goto seccomp_return;
}
rc = seccomp_attr_set(ctx, SCMP_FLTATR_CTL_TSYNC, 1);
if (rc != 0) {
error_setg_errno(errp, -rc,
"failed to set seccomp thread synchronization");
goto seccomp_return;
}
@ -182,15 +184,21 @@ static int seccomp_start(uint32_t seccomp_opts)
rc = seccomp_rule_add_array(ctx, action, blacklist[i].num,
blacklist[i].narg, blacklist[i].arg_cmp);
if (rc < 0) {
error_setg_errno(errp, -rc,
"failed to add seccomp blacklist rules");
goto seccomp_return;
}
}
rc = seccomp_load(ctx);
if (rc < 0) {
error_setg_errno(errp, -rc,
"failed to load seccomp syscall filter in kernel");
}
seccomp_return:
seccomp_release(ctx);
return rc;
return rc < 0 ? -1 : 0;
}
#ifdef CONFIG_SECCOMP
@ -260,9 +268,7 @@ int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
}
}
if (seccomp_start(seccomp_opts) < 0) {
error_setg(errp, "failed to install seccomp syscall filter "
"in the kernel");
if (seccomp_start(seccomp_opts, errp) < 0) {
return -1;
}
}