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Commit d67c0621 by Stéphane Graber Committed by GitHub
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Merge pull request #1144 from brauner/2016-08-19/seccomp_non_functional_changes

seccomp: non functional changes
parents 2d7821e5 f06c6207
Showing with 76 additions and 68 deletions
src/lxc/seccomp.c
......@@ -47,11 +47,11 @@ static int parse_config_v1(FILE *f, struct lxc_conf *conf)
return -1;
ret = seccomp_rule_add(
#if HAVE_SCMP_FILTER_CTX
conf->seccomp_ctx,
conf->seccomp_ctx,
#endif
SCMP_ACT_ALLOW, nr, 0);
SCMP_ACT_ALLOW, nr, 0);
if (ret < 0) {
ERROR("failed loading allow rule for %d", nr);
ERROR("Failed loading allow rule for %d.", nr);
return ret;
}
}
......@@ -73,14 +73,15 @@ static uint32_t get_v2_default_action(char *line)
{
uint32_t ret_action = -1;
while (*line == ' ') line++;
while (*line == ' ')
line++;
// after 'whitelist' or 'blacklist' comes default behavior
if (strncmp(line, "kill", 4) == 0)
ret_action = SCMP_ACT_KILL;
else if (strncmp(line, "errno", 5) == 0) {
int e;
if (sscanf(line+5, "%d", &e) != 1) {
ERROR("Bad errno value in %s", line);
if (sscanf(line + 5, "%d", &e) != 1) {
ERROR("Bad errno value in %s.", line);
return -2;
}
ret_action = SCMP_ACT_ERRNO(e);
......@@ -146,7 +147,7 @@ int get_hostarch(void)
{
struct utsname uts;
if (uname(&uts) < 0) {
SYSERROR("Failed to read host arch");
SYSERROR("Failed to read host arch.");
return -1;
}
if (strcmp(uts.machine, "i686") == 0)
......@@ -209,18 +210,18 @@ scmp_filter_ctx get_new_ctx(enum lxc_hostarch_t n_arch, uint32_t default_policy_
}
if ((ctx = seccomp_init(default_policy_action)) == NULL) {
ERROR("Error initializing seccomp context");
ERROR("Error initializing seccomp context.");
return NULL;
}
if (seccomp_attr_set(ctx, SCMP_FLTATR_CTL_NNP, 0)) {
ERROR("failed to turn off n-new-privs");
ERROR("Failed to turn off n-new-privs.");
seccomp_release(ctx);
return NULL;
}
ret = seccomp_arch_add(ctx, arch);
if (ret != 0) {
ERROR("Seccomp error %d (%s) adding arch: %d", ret,
strerror(-ret), (int)n_arch);
strerror(-ret), (int)n_arch);
seccomp_release(ctx);
return NULL;
}
......@@ -238,17 +239,22 @@ bool do_resolve_add_rule(uint32_t arch, char *line, scmp_filter_ctx ctx,
{
int nr, ret;
if (arch && seccomp_arch_exist(ctx, arch) != 0) {
ERROR("BUG: seccomp: rule and context arch do not match (arch %d)", arch);
ret = seccomp_arch_exist(ctx, arch);
if (arch && ret != 0) {
ERROR("BUG: Seccomp: rule and context arch do not match (arch "
"%d): %s.",
arch, strerror(-ret));
return false;
}
if (strncmp(line, "reject_force_umount", 19) == 0) {
INFO("Setting seccomp rule to reject force umounts\n");
INFO("Setting Seccomp rule to reject force umounts.");
ret = seccomp_rule_add_exact(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(umount2),
1, SCMP_A1(SCMP_CMP_MASKED_EQ , MNT_FORCE , MNT_FORCE ));
if (ret < 0) {
ERROR("failed (%d) loading rule to reject force umount", ret);
ERROR("Failed (%d) loading rule to reject force "
"umount: %s.",
ret, strerror(-ret));
return false;
}
return true;
......@@ -256,18 +262,19 @@ bool do_resolve_add_rule(uint32_t arch, char *line, scmp_filter_ctx ctx,
nr = seccomp_syscall_resolve_name(line);
if (nr == __NR_SCMP_ERROR) {
WARN("Seccomp: failed to resolve syscall: %s", line);
WARN("This syscall will NOT be blacklisted");
WARN("Seccomp: failed to resolve syscall: %s.", line);
WARN("This syscall will NOT be blacklisted.");
return true;
}
if (nr < 0) {
WARN("Seccomp: got negative # for syscall: %s", line);
WARN("This syscall will NOT be blacklisted");
WARN("Seccomp: got negative for syscall: %d: %s.", nr, line);
WARN("This syscall will NOT be blacklisted.");
return true;
}
ret = seccomp_rule_add_exact(ctx, action, nr, 0);
if (ret < 0) {
ERROR("failed (%d) loading rule for %s (nr %d action %d)", ret, line, nr, action);
ERROR("Failed (%d) loading rule for %s (nr %d action %d): %s.",
ret, line, nr, action, strerror(-ret));
return false;
}
return true;
......@@ -291,22 +298,22 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
{
char *p;
int ret;
scmp_filter_ctx compat_ctx[2] = { NULL, NULL };
scmp_filter_ctx compat_ctx[2] = {NULL, NULL};
bool blacklist = false;
uint32_t default_policy_action = -1, default_rule_action = -1, action;
enum lxc_hostarch_t native_arch = get_hostarch(),
cur_rule_arch = native_arch;
uint32_t compat_arch[2] = { SCMP_ARCH_NATIVE, SCMP_ARCH_NATIVE };
uint32_t compat_arch[2] = {SCMP_ARCH_NATIVE, SCMP_ARCH_NATIVE};
if (strncmp(line, "blacklist", 9) == 0)
blacklist = true;
else if (strncmp(line, "whitelist", 9) != 0) {
ERROR("Bad seccomp policy style: %s", line);
ERROR("Bad seccomp policy style: %s.", line);
return -1;
}
if ((p = strchr(line, ' '))) {
default_policy_action = get_v2_default_action(p+1);
default_policy_action = get_v2_default_action(p + 1);
if (default_policy_action == -2)
return -1;
}
......@@ -385,11 +392,11 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
if (default_policy_action != SCMP_ACT_KILL) {
ret = seccomp_reset(conf->seccomp_ctx, default_policy_action);
if (ret != 0) {
ERROR("Error re-initializing seccomp");
ERROR("Error re-initializing Seccomp.");
return -1;
}
if (seccomp_attr_set(conf->seccomp_ctx, SCMP_FLTATR_CTL_NNP, 0)) {
ERROR("failed to turn off n-new-privs");
ERROR("Failed to turn off n-new-privs.");
return -1;
}
}
......@@ -405,7 +412,7 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
if (line[0] == '[') {
// read the architecture for next set of rules
if (strcmp(line, "[x86]") == 0 ||
strcmp(line, "[X86]") == 0) {
strcmp(line, "[X86]") == 0) {
if (native_arch != lxc_seccomp_arch_i386 &&
native_arch != lxc_seccomp_arch_amd64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
......@@ -413,19 +420,19 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
}
cur_rule_arch = lxc_seccomp_arch_i386;
} else if (strcmp(line, "[X86_64]") == 0 ||
strcmp(line, "[x86_64]") == 0) {
strcmp(line, "[x86_64]") == 0) {
if (native_arch != lxc_seccomp_arch_amd64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
}
cur_rule_arch = lxc_seccomp_arch_amd64;
} else if (strcmp(line, "[all]") == 0 ||
strcmp(line, "[ALL]") == 0) {
strcmp(line, "[ALL]") == 0) {
cur_rule_arch = lxc_seccomp_arch_all;
}
#ifdef SCMP_ARCH_ARM
else if (strcmp(line, "[arm]") == 0 ||
strcmp(line, "[ARM]") == 0) {
strcmp(line, "[ARM]") == 0) {
if (native_arch != lxc_seccomp_arch_arm &&
native_arch != lxc_seccomp_arch_arm64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
......@@ -436,7 +443,7 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
#endif
#ifdef SCMP_ARCH_AARCH64
else if (strcmp(line, "[arm64]") == 0 ||
strcmp(line, "[ARM64]") == 0) {
strcmp(line, "[ARM64]") == 0) {
if (native_arch != lxc_seccomp_arch_arm64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
......@@ -446,7 +453,7 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
#endif
#ifdef SCMP_ARCH_PPC64LE
else if (strcmp(line, "[ppc64le]") == 0 ||
strcmp(line, "[PPC64LE]") == 0) {
strcmp(line, "[PPC64LE]") == 0) {
if (native_arch != lxc_seccomp_arch_ppc64le) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
......@@ -456,7 +463,7 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
#endif
#ifdef SCMP_ARCH_PPC64
else if (strcmp(line, "[ppc64]") == 0 ||
strcmp(line, "[PPC64]") == 0) {
strcmp(line, "[PPC64]") == 0) {
if (native_arch != lxc_seccomp_arch_ppc64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
......@@ -466,7 +473,7 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
#endif
#ifdef SCMP_ARCH_PPC
else if (strcmp(line, "[ppc]") == 0 ||
strcmp(line, "[PPC]") == 0) {
strcmp(line, "[PPC]") == 0) {
if (native_arch != lxc_seccomp_arch_ppc &&
native_arch != lxc_seccomp_arch_ppc64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
......@@ -477,21 +484,21 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
#endif
#ifdef SCMP_ARCH_MIPS
else if (strcmp(line, "[mips64]") == 0 ||
strcmp(line, "[MIPS64]") == 0) {
strcmp(line, "[MIPS64]") == 0) {
if (native_arch != lxc_seccomp_arch_mips64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
}
cur_rule_arch = lxc_seccomp_arch_mips64;
} else if (strcmp(line, "[mips64n32]") == 0 ||
strcmp(line, "[MIPS64N32]") == 0) {
strcmp(line, "[MIPS64N32]") == 0) {
if (native_arch != lxc_seccomp_arch_mips64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
}
cur_rule_arch = lxc_seccomp_arch_mips64n32;
} else if (strcmp(line, "[mips]") == 0 ||
strcmp(line, "[MIPS]") == 0) {
strcmp(line, "[MIPS]") == 0) {
if (native_arch != lxc_seccomp_arch_mips &&
native_arch != lxc_seccomp_arch_mips64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
......@@ -499,21 +506,21 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
}
cur_rule_arch = lxc_seccomp_arch_mips;
} else if (strcmp(line, "[mipsel64]") == 0 ||
strcmp(line, "[MIPSEL64]") == 0) {
strcmp(line, "[MIPSEL64]") == 0) {
if (native_arch != lxc_seccomp_arch_mipsel64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
}
cur_rule_arch = lxc_seccomp_arch_mipsel64;
} else if (strcmp(line, "[mipsel64n32]") == 0 ||
strcmp(line, "[MIPSEL64N32]") == 0) {
strcmp(line, "[MIPSEL64N32]") == 0) {
if (native_arch != lxc_seccomp_arch_mipsel64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
}
cur_rule_arch = lxc_seccomp_arch_mipsel64n32;
} else if (strcmp(line, "[mipsel]") == 0 ||
strcmp(line, "[MIPSEL]") == 0) {
strcmp(line, "[MIPSEL]") == 0) {
if (native_arch != lxc_seccomp_arch_mipsel &&
native_arch != lxc_seccomp_arch_mipsel64) {
cur_rule_arch = lxc_seccomp_arch_unknown;
......@@ -524,7 +531,7 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
#endif
#ifdef SCMP_ARCH_S390X
else if (strcmp(line, "[s390x]") == 0 ||
strcmp(line, "[S390X]") == 0) {
strcmp(line, "[S390X]") == 0) {
if (native_arch != lxc_seccomp_arch_s390x) {
cur_rule_arch = lxc_seccomp_arch_unknown;
continue;
......@@ -545,14 +552,14 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
/* read optional action which follows the syscall */
action = get_and_clear_v2_action(line, default_rule_action);
if (action == -1) {
ERROR("Failed to interpret action");
ERROR("Failed to interpret action.");
goto bad_rule;
}
if (cur_rule_arch == native_arch ||
cur_rule_arch == lxc_seccomp_arch_native ||
compat_arch[0] == SCMP_ARCH_NATIVE) {
INFO("Adding native rule for %s action %d", line, action);
INFO("Adding native rule for %s action %d.", line, action);
if (!do_resolve_add_rule(SCMP_ARCH_NATIVE, line, conf->seccomp_ctx, action))
goto bad_rule;
}
......@@ -561,15 +568,15 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
cur_rule_arch == lxc_seccomp_arch_mips64n32 ||
cur_rule_arch == lxc_seccomp_arch_mipsel64n32 ? 1 : 0;
INFO("Adding compat-only rule for %s action %d", line, action);
INFO("Adding compat-only rule for %s action %d.", line, action);
if (!do_resolve_add_rule(compat_arch[arch_index], line, compat_ctx[arch_index], action))
goto bad_rule;
}
else {
INFO("Adding native rule for %s action %d", line, action);
INFO("Adding native rule for %s action %d.", line, action);
if (!do_resolve_add_rule(SCMP_ARCH_NATIVE, line, conf->seccomp_ctx, action))
goto bad_rule;
INFO("Adding compat rule for %s action %d", line, action);
INFO("Adding compat rule for %s action %d.", line, action);
if (!do_resolve_add_rule(compat_arch[0], line, compat_ctx[0], action))
goto bad_rule;
if (compat_arch[1] != SCMP_ARCH_NATIVE &&
......@@ -579,10 +586,10 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
}
if (compat_ctx[0]) {
INFO("Merging in the compat seccomp ctx into the main one");
INFO("Merging in the compat Seccomp ctx into the main one.");
if (seccomp_merge(conf->seccomp_ctx, compat_ctx[0]) != 0 ||
(compat_ctx[1] != NULL && seccomp_merge(conf->seccomp_ctx, compat_ctx[1]) != 0)) {
ERROR("Error merging compat seccomp contexts");
ERROR("Error merging compat Seccomp contexts.");
goto bad;
}
}
......@@ -590,7 +597,7 @@ static int parse_config_v2(FILE *f, char *line, struct lxc_conf *conf)
return 0;
bad_arch:
ERROR("Unsupported arch: %s", line);
ERROR("Unsupported arch: %s.", line);
bad_rule:
bad:
if (compat_ctx[0])
......@@ -621,20 +628,20 @@ static int parse_config(FILE *f, struct lxc_conf *conf)
ret = fscanf(f, "%d\n", &version);
if (ret != 1 || (version != 1 && version != 2)) {
ERROR("invalid version");
ERROR("Invalid version.");
return -1;
}
if (!fgets(line, 1024, f)) {
ERROR("invalid config file");
ERROR("Invalid config file.");
return -1;
}
if (version == 1 && !strstr(line, "whitelist")) {
ERROR("only whitelist policy is supported");
ERROR("Only whitelist policy is supported.");
return -1;
}
if (strstr(line, "debug")) {
ERROR("debug not yet implemented");
ERROR("Debug not yet implemented.");
return -1;
}
......@@ -664,7 +671,7 @@ static bool use_seccomp(void)
while (fgets(line, 1024, f)) {
if (strncmp(line, "Seccomp:", 8) == 0) {
found = true;
ret = sscanf(line+8, "%d", &v);
ret = sscanf(line + 8, "%d", &v);
if (ret == 1 && v != 0)
already_enabled = true;
break;
......@@ -672,12 +679,12 @@ static bool use_seccomp(void)
}
fclose(f);
if (!found) { /* no Seccomp line, no seccomp in kernel */
INFO("Seccomp is not enabled in the kernel");
if (!found) { /* no Seccomp line, no seccomp in kernel */
INFO("Seccomp is not enabled in the kernel.");
return false;
}
if (already_enabled) { /* already seccomp-confined */
INFO("Already seccomp-confined, not loading new policy");
if (already_enabled) { /* already seccomp-confined */
INFO("Already seccomp-confined, not loading new policy.");
return false;
}
return true;
......@@ -702,25 +709,25 @@ int lxc_read_seccomp_config(struct lxc_conf *conf)
ret = seccomp_init(SCMP_ACT_KILL) < 0;
#endif
if (ret) {
ERROR("failed initializing seccomp");
ERROR("Failed initializing seccomp.");
return -1;
}
/* turn of no-new-privs. We don't want it in lxc, and it breaks
* with apparmor */
/* turn of no-new-privs. We don't want it in lxc, and it breaks
* with apparmor */
#if HAVE_SCMP_FILTER_CTX
check_seccomp_attr_set = seccomp_attr_set(conf->seccomp_ctx, SCMP_FLTATR_CTL_NNP, 0);
check_seccomp_attr_set = seccomp_attr_set(conf->seccomp_ctx, SCMP_FLTATR_CTL_NNP, 0);
#else
check_seccomp_attr_set = seccomp_attr_set(SCMP_FLTATR_CTL_NNP, 0);
check_seccomp_attr_set = seccomp_attr_set(SCMP_FLTATR_CTL_NNP, 0);
#endif
if (check_seccomp_attr_set) {
ERROR("failed to turn off n-new-privs");
ERROR("Failed to turn off n-new-privs.");
return -1;
}
f = fopen(conf->seccomp, "r");
if (!f) {
SYSERROR("failed to open seccomp policy file %s", conf->seccomp);
SYSERROR("Failed to open seccomp policy file %s.", conf->seccomp);
return -1;
}
ret = parse_config(f, conf);
......@@ -737,17 +744,18 @@ int lxc_seccomp_load(struct lxc_conf *conf)
return 0;
ret = seccomp_load(
#if HAVE_SCMP_FILTER_CTX
conf->seccomp_ctx
conf->seccomp_ctx
#endif
);
);
if (ret < 0) {
ERROR("Error loading the seccomp policy");
ERROR("Error loading the seccomp policy.");
return -1;
}
return 0;
}
void lxc_seccomp_free(struct lxc_conf *conf) {
void lxc_seccomp_free(struct lxc_conf *conf)
{
free(conf->seccomp);
conf->seccomp = NULL;
#if HAVE_SCMP_FILTER_CTX
......
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