On Wed, Aug 02, 2023 at 10:44:34AM -0700, Casey Schaufler wrote: > Add selftests for the three system calls supporting the LSM > infrastructure. This set of tests is limited by the differences > in access policy enforced by the existing security modules. > > Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx> I know these are just testcases, but a few things stood out below. The actual set of tests looks good, though. Thanks. > --- > MAINTAINERS | 1 + > tools/testing/selftests/Makefile | 1 + > tools/testing/selftests/lsm/Makefile | 19 ++ > tools/testing/selftests/lsm/common.c | 81 ++++++ > tools/testing/selftests/lsm/common.h | 33 +++ > tools/testing/selftests/lsm/config | 3 + > .../selftests/lsm/lsm_get_self_attr_test.c | 240 ++++++++++++++++++ > .../selftests/lsm/lsm_list_modules_test.c | 140 ++++++++++ > .../selftests/lsm/lsm_set_self_attr_test.c | 74 ++++++ > 9 files changed, 592 insertions(+) > create mode 100644 tools/testing/selftests/lsm/Makefile > create mode 100644 tools/testing/selftests/lsm/common.c > create mode 100644 tools/testing/selftests/lsm/common.h > create mode 100644 tools/testing/selftests/lsm/config > create mode 100644 tools/testing/selftests/lsm/lsm_get_self_attr_test.c > create mode 100644 tools/testing/selftests/lsm/lsm_list_modules_test.c > create mode 100644 tools/testing/selftests/lsm/lsm_set_self_attr_test.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index aca4db11dd02..c96f1c388d22 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -19158,6 +19158,7 @@ W: http://kernsec.org/ > T: git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm.git > F: include/uapi/linux/lsm.h > F: security/ > +F: tools/testing/selftests/lsm/ > X: security/selinux/ > > SELINUX SECURITY MODULE > diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile > index 666b56f22a41..bde7c217b23f 100644 > --- a/tools/testing/selftests/Makefile > +++ b/tools/testing/selftests/Makefile > @@ -39,6 +39,7 @@ TARGETS += landlock > TARGETS += lib > TARGETS += livepatch > TARGETS += lkdtm > +TARGETS += lsm > TARGETS += membarrier > TARGETS += memfd > TARGETS += memory-hotplug > diff --git a/tools/testing/selftests/lsm/Makefile b/tools/testing/selftests/lsm/Makefile > new file mode 100644 > index 000000000000..bae6c1e3bba4 > --- /dev/null > +++ b/tools/testing/selftests/lsm/Makefile > @@ -0,0 +1,19 @@ > +# SPDX-License-Identifier: GPL-2.0 > +# > +# First run: make -C ../../../.. headers_install > + > +CFLAGS += -Wall -O2 $(KHDR_INCLUDES) > +LOCAL_HDRS += common.h > + > +TEST_GEN_PROGS := lsm_get_self_attr_test lsm_list_modules_test \ > + lsm_set_self_attr_test > + > +include ../lib.mk > + > +$(TEST_GEN_PROGS): > + > +$(OUTPUT)/lsm_get_self_attr_test: lsm_get_self_attr_test.c common.c > +$(OUTPUT)/lsm_set_self_attr_test: lsm_set_self_attr_test.c common.c > +$(OUTPUT)/lsm_list_modules_test: lsm_list_modules_test.c common.c > + > +EXTRA_CLEAN = $(OUTPUT)/common.o > diff --git a/tools/testing/selftests/lsm/common.c b/tools/testing/selftests/lsm/common.c > new file mode 100644 > index 000000000000..db9af9375238 > --- /dev/null > +++ b/tools/testing/selftests/lsm/common.c > @@ -0,0 +1,81 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Linux Security Module infrastructure tests > + * > + * Copyright © 2023 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> > + */ > + > +#define _GNU_SOURCE > +#include <linux/lsm.h> > +#include <fcntl.h> > +#include <string.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <unistd.h> > +#include <sys/types.h> > +#include "common.h" > + > +#define PROCATTR "/proc/self/attr/" > + > +int read_proc_attr(const char *attr, char *value, size_t size) > +{ > + int fd; > + int len; > + char *path; > + > + len = strlen(PROCATTR) + strlen(attr) + 1; > + path = calloc(len, 1); > + if (path == NULL) > + return -1; > + sprintf(path, "%s%s", PROCATTR, attr); > + > + fd = open(path, O_RDONLY); > + free(path); > + > + if (fd < 0) not closing fd here > + return -1; > + len = read(fd, value, size); > + if (len <= 0) > + return -1; > + close(fd); > + It would feel cozier if you would ensure a trailing \0 in value before doing strchr. > + path = strchr(value, '\n'); > + if (path) > + *path = '\0'; > + > + return 0; > +} > + > +int read_sysfs_lsms(char *lsms, size_t size) > +{ > + FILE *fp; > + > + fp = fopen("/sys/kernel/security/lsm", "r"); > + if (fp == NULL) > + return -1; > + if (fread(lsms, 1, size, fp) <= 0) not closing fp > + return -1; > + fclose(fp); > + return 0; > +} > + > +int attr_lsm_count(void) > +{ > + char *names = calloc(sysconf(_SC_PAGESIZE), 1); > + int count = 0; > + > + if (!names) > + return 0; > + > + if (read_sysfs_lsms(names, sysconf(_SC_PAGESIZE))) > + return 0; > + Again strstr without ensuring \0. /sys/kernel/security/lsm is unlikely to be longer than _SC_PAGESIZE, but I *could* mess with you with a bind mount... > + if (strstr(names, "selinux")) > + count++; > + if (strstr(names, "smack")) > + count++; > + if (strstr(names, "apparmor")) > + count++; > + > + return count; > +} > diff --git a/tools/testing/selftests/lsm/common.h b/tools/testing/selftests/lsm/common.h > new file mode 100644 > index 000000000000..cd0214a3eeb2 > --- /dev/null > +++ b/tools/testing/selftests/lsm/common.h > @@ -0,0 +1,33 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Linux Security Module infrastructure tests > + * > + * Copyright © 2023 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> > + */ > + > +#ifndef lsm_get_self_attr > +static inline int lsm_get_self_attr(unsigned int attr, struct lsm_ctx *ctx, > + size_t *size, __u32 flags) > +{ > + return syscall(__NR_lsm_get_self_attr, attr, ctx, size, flags); > +} > +#endif > + > +#ifndef lsm_set_self_attr > +static inline int lsm_set_self_attr(unsigned int attr, struct lsm_ctx *ctx, > + size_t size, __u32 flags) > +{ > + return syscall(__NR_lsm_set_self_attr, attr, ctx, size, flags); > +} > +#endif > + > +#ifndef lsm_list_modules > +static inline int lsm_list_modules(__u64 *ids, size_t *size, __u32 flags) > +{ > + return syscall(__NR_lsm_list_modules, ids, size, flags); > +} > +#endif > + > +extern int read_proc_attr(const char *attr, char *value, size_t size); > +extern int read_sysfs_lsms(char *lsms, size_t size); > +int attr_lsm_count(void); > diff --git a/tools/testing/selftests/lsm/config b/tools/testing/selftests/lsm/config > new file mode 100644 > index 000000000000..1c0c4c020f9c > --- /dev/null > +++ b/tools/testing/selftests/lsm/config > @@ -0,0 +1,3 @@ > +CONFIG_SYSFS=y > +CONFIG_SECURITY=y > +CONFIG_SECURITYFS=y > diff --git a/tools/testing/selftests/lsm/lsm_get_self_attr_test.c b/tools/testing/selftests/lsm/lsm_get_self_attr_test.c > new file mode 100644 > index 000000000000..74c65aae1fcc > --- /dev/null > +++ b/tools/testing/selftests/lsm/lsm_get_self_attr_test.c > @@ -0,0 +1,240 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Linux Security Module infrastructure tests > + * Tests for the lsm_get_self_attr system call > + * > + * Copyright © 2022 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> > + */ > + > +#define _GNU_SOURCE > +#include <linux/lsm.h> > +#include <fcntl.h> > +#include <string.h> > +#include <stdio.h> > +#include <unistd.h> > +#include <sys/types.h> > +#include "../kselftest_harness.h" > +#include "common.h" > + > +static struct lsm_ctx *next_ctx(struct lsm_ctx *ctxp) > +{ > + void *vp; > + > + vp = (void *)ctxp + sizeof(*ctxp) + ctxp->ctx_len; > + return (struct lsm_ctx *)vp; > +} > + > +TEST(size_null_lsm_get_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + struct lsm_ctx *ctx = calloc(page_size, 1); > + > + ASSERT_NE(NULL, ctx); > + errno = 0; > + ASSERT_EQ(-1, lsm_get_self_attr(LSM_ATTR_CURRENT, ctx, NULL, 0)); > + ASSERT_EQ(EINVAL, errno); > + > + free(ctx); > +} > + > +TEST(ctx_null_lsm_get_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + size_t size = page_size; > + int rc; > + > + rc = lsm_get_self_attr(LSM_ATTR_CURRENT, NULL, &size, 0); > + > + if (attr_lsm_count()) { > + ASSERT_NE(-1, rc); > + ASSERT_NE(1, size); > + } else { > + ASSERT_EQ(-1, rc); > + } > +} > + > +TEST(size_too_small_lsm_get_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + struct lsm_ctx *ctx = calloc(page_size, 1); > + size_t size = 1; > + > + ASSERT_NE(NULL, ctx); > + errno = 0; > + ASSERT_EQ(-1, lsm_get_self_attr(LSM_ATTR_CURRENT, ctx, &size, 0)); > + if (attr_lsm_count()) { > + ASSERT_EQ(E2BIG, errno); > + } else { > + ASSERT_EQ(EOPNOTSUPP, errno); > + } > + ASSERT_NE(1, size); > + > + free(ctx); > +} > + > +TEST(flags_zero_lsm_get_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + struct lsm_ctx *ctx = calloc(page_size, 1); > + size_t size = page_size; > + > + ASSERT_NE(NULL, ctx); > + errno = 0; > + ASSERT_EQ(-1, lsm_get_self_attr(LSM_ATTR_CURRENT, ctx, &size, 1)); > + ASSERT_EQ(EINVAL, errno); > + ASSERT_EQ(page_size, size); > + > + free(ctx); > +} > + > +TEST(flags_overset_lsm_get_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + struct lsm_ctx *ctx = calloc(page_size, 1); > + size_t size = page_size; > + > + ASSERT_NE(NULL, ctx); > + errno = 0; > + ASSERT_EQ(-1, lsm_get_self_attr(LSM_ATTR_CURRENT | LSM_ATTR_PREV, ctx, > + &size, 0)); > + ASSERT_EQ(EOPNOTSUPP, errno); > + > + free(ctx); > +} > + > +TEST(basic_lsm_get_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + size_t size = page_size; > + struct lsm_ctx *ctx = calloc(page_size, 1); > + struct lsm_ctx *tctx = NULL; > + __u64 *syscall_lsms = calloc(page_size, 1); > + char *attr = calloc(page_size, 1); You never verify attr is not NULL > + int cnt_current = 0; > + int cnt_exec = 0; > + int cnt_fscreate = 0; > + int cnt_keycreate = 0; > + int cnt_prev = 0; > + int cnt_sockcreate = 0; > + int lsmcount; > + int count; > + int i; > + > + ASSERT_NE(NULL, ctx); > + ASSERT_NE(NULL, syscall_lsms); > + > + lsmcount = syscall(__NR_lsm_list_modules, syscall_lsms, &size, 0); > + ASSERT_LE(1, lsmcount); > + > + for (i = 0; i < lsmcount; i++) { > + switch (syscall_lsms[i]) { > + case LSM_ID_SELINUX: > + cnt_current++; > + cnt_exec++; > + cnt_fscreate++; > + cnt_keycreate++; > + cnt_prev++; > + cnt_sockcreate++; > + break; > + case LSM_ID_SMACK: > + cnt_current++; > + break; > + case LSM_ID_APPARMOR: > + cnt_current++; > + cnt_exec++; > + cnt_prev++; > + break; > + default: > + break; > + } > + } > + > + if (cnt_current) { > + size = page_size; > + count = lsm_get_self_attr(LSM_ATTR_CURRENT, ctx, &size, 0); > + ASSERT_EQ(cnt_current, count); > + tctx = ctx; > + ASSERT_EQ(0, read_proc_attr("current", attr, page_size)); > + ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr)); > + for (i = 1; i < count; i++) { > + tctx = next_ctx(tctx); > + ASSERT_NE(0, strcmp((char *)tctx->ctx, attr)); > + } > + } > + if (cnt_exec) { > + size = page_size; > + count = lsm_get_self_attr(LSM_ATTR_EXEC, ctx, &size, 0); > + ASSERT_GE(cnt_exec, count); > + if (count > 0) { > + tctx = ctx; > + if (read_proc_attr("exec", attr, page_size) == 0) > + ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr)); > + } > + for (i = 1; i < count; i++) { > + tctx = next_ctx(tctx); > + ASSERT_NE(0, strcmp((char *)tctx->ctx, attr)); > + } > + } > + if (cnt_fscreate) { > + size = page_size; > + count = lsm_get_self_attr(LSM_ATTR_FSCREATE, ctx, &size, 0); > + ASSERT_GE(cnt_fscreate, count); > + if (count > 0) { > + tctx = ctx; > + if (read_proc_attr("fscreate", attr, page_size) == 0) > + ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr)); > + } > + for (i = 1; i < count; i++) { > + tctx = next_ctx(tctx); > + ASSERT_NE(0, strcmp((char *)tctx->ctx, attr)); > + } > + } > + if (cnt_keycreate) { > + size = page_size; > + count = lsm_get_self_attr(LSM_ATTR_KEYCREATE, ctx, &size, 0); > + ASSERT_GE(cnt_keycreate, count); > + if (count > 0) { > + tctx = ctx; > + if (read_proc_attr("keycreate", attr, page_size) == 0) > + ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr)); > + } > + for (i = 1; i < count; i++) { > + tctx = next_ctx(tctx); > + ASSERT_NE(0, strcmp((char *)tctx->ctx, attr)); > + } > + } > + if (cnt_prev) { > + size = page_size; > + count = lsm_get_self_attr(LSM_ATTR_PREV, ctx, &size, 0); > + ASSERT_GE(cnt_prev, count); > + if (count > 0) { > + tctx = ctx; > + ASSERT_EQ(0, read_proc_attr("prev", attr, page_size)); > + ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr)); > + for (i = 1; i < count; i++) { > + tctx = next_ctx(tctx); > + ASSERT_NE(0, strcmp((char *)tctx->ctx, attr)); > + } > + } > + } > + if (cnt_sockcreate) { > + size = page_size; > + count = lsm_get_self_attr(LSM_ATTR_SOCKCREATE, ctx, &size, 0); > + ASSERT_GE(cnt_sockcreate, count); > + if (count > 0) { > + tctx = ctx; > + if (read_proc_attr("sockcreate", attr, page_size) == 0) > + ASSERT_EQ(0, strcmp((char *)tctx->ctx, attr)); > + } > + for (i = 1; i < count; i++) { > + tctx = next_ctx(tctx); > + ASSERT_NE(0, strcmp((char *)tctx->ctx, attr)); > + } > + } > + > + free(ctx); > + free(attr); > + free(syscall_lsms); > +} > + > +TEST_HARNESS_MAIN > diff --git a/tools/testing/selftests/lsm/lsm_list_modules_test.c b/tools/testing/selftests/lsm/lsm_list_modules_test.c > new file mode 100644 > index 000000000000..445c02f09c74 > --- /dev/null > +++ b/tools/testing/selftests/lsm/lsm_list_modules_test.c > @@ -0,0 +1,140 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Linux Security Module infrastructure tests > + * Tests for the lsm_list_modules system call > + * > + * Copyright © 2022 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> > + */ > + > +#define _GNU_SOURCE > +#include <linux/lsm.h> > +#include <string.h> > +#include <stdio.h> > +#include <unistd.h> > +#include <sys/types.h> > +#include "../kselftest_harness.h" > +#include "common.h" > + > +TEST(size_null_lsm_list_modules) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + __u64 *syscall_lsms = calloc(page_size, 1); > + > + ASSERT_NE(NULL, syscall_lsms); > + errno = 0; > + ASSERT_EQ(-1, lsm_list_modules(syscall_lsms, NULL, 0)); > + ASSERT_EQ(EFAULT, errno); > + > + free(syscall_lsms); > +} > + > +TEST(ids_null_lsm_list_modules) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + size_t size = page_size; > + > + errno = 0; > + ASSERT_EQ(-1, lsm_list_modules(NULL, &size, 0)); > + ASSERT_EQ(EFAULT, errno); > + ASSERT_NE(1, size); > +} > + > +TEST(size_too_small_lsm_list_modules) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + __u64 *syscall_lsms = calloc(page_size, 1); > + size_t size = 1; > + > + ASSERT_NE(NULL, syscall_lsms); > + errno = 0; > + ASSERT_EQ(-1, lsm_list_modules(syscall_lsms, &size, 0)); > + ASSERT_EQ(E2BIG, errno); > + ASSERT_NE(1, size); > + > + free(syscall_lsms); > +} > + > +TEST(flags_set_lsm_list_modules) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + __u64 *syscall_lsms = calloc(page_size, 1); > + size_t size = page_size; > + > + ASSERT_NE(NULL, syscall_lsms); > + errno = 0; > + ASSERT_EQ(-1, lsm_list_modules(syscall_lsms, &size, 7)); > + ASSERT_EQ(EINVAL, errno); > + ASSERT_EQ(page_size, size); > + > + free(syscall_lsms); > +} > + > +TEST(correct_lsm_list_modules) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + size_t size = page_size; > + __u64 *syscall_lsms = calloc(page_size, 1); > + char *sysfs_lsms = calloc(page_size, 1); > + char *name; > + char *cp; > + int count; > + int i; > + > + ASSERT_NE(NULL, sysfs_lsms); > + ASSERT_NE(NULL, syscall_lsms); > + ASSERT_EQ(0, read_sysfs_lsms(sysfs_lsms, page_size)); > + > + count = lsm_list_modules(syscall_lsms, &size, 0); > + ASSERT_LE(1, count); > + cp = sysfs_lsms; > + for (i = 0; i < count; i++) { > + switch (syscall_lsms[i]) { > + case LSM_ID_CAPABILITY: > + name = "capability"; > + break; > + case LSM_ID_SELINUX: > + name = "selinux"; > + break; > + case LSM_ID_SMACK: > + name = "smack"; > + break; > + case LSM_ID_TOMOYO: > + name = "tomoyo"; > + break; > + case LSM_ID_IMA: > + name = "ima"; > + break; > + case LSM_ID_APPARMOR: > + name = "apparmor"; > + break; > + case LSM_ID_YAMA: > + name = "yama"; > + break; > + case LSM_ID_LOADPIN: > + name = "loadpin"; > + break; > + case LSM_ID_SAFESETID: > + name = "safesetid"; > + break; > + case LSM_ID_LOCKDOWN: > + name = "lockdown"; > + break; > + case LSM_ID_BPF: > + name = "bpf"; > + break; > + case LSM_ID_LANDLOCK: > + name = "landlock"; > + break; > + default: > + name = "INVALID"; > + break; > + } > + ASSERT_EQ(0, strncmp(cp, name, strlen(name))); > + cp += strlen(name) + 1; > + } > + > + free(sysfs_lsms); > + free(syscall_lsms); > +} > + > +TEST_HARNESS_MAIN > diff --git a/tools/testing/selftests/lsm/lsm_set_self_attr_test.c b/tools/testing/selftests/lsm/lsm_set_self_attr_test.c > new file mode 100644 > index 000000000000..d0f5b776c548 > --- /dev/null > +++ b/tools/testing/selftests/lsm/lsm_set_self_attr_test.c > @@ -0,0 +1,74 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Linux Security Module infrastructure tests > + * Tests for the lsm_set_self_attr system call > + * > + * Copyright © 2022 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> > + */ > + > +#define _GNU_SOURCE > +#include <linux/lsm.h> > +#include <string.h> > +#include <stdio.h> > +#include <unistd.h> > +#include <sys/types.h> > +#include "../kselftest_harness.h" > +#include "common.h" > + > +TEST(ctx_null_lsm_set_self_attr) > +{ > + ASSERT_EQ(-1, lsm_set_self_attr(LSM_ATTR_CURRENT, NULL, > + sizeof(struct lsm_ctx), 0)); > +} > + > +TEST(size_too_small_lsm_set_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + struct lsm_ctx *ctx = calloc(page_size, 1); > + size_t size = page_size; > + > + ASSERT_NE(NULL, ctx); > + if (attr_lsm_count()) { > + ASSERT_LE(1, lsm_get_self_attr(LSM_ATTR_CURRENT, ctx, &size, > + 0)); > + } > + ASSERT_EQ(-1, lsm_set_self_attr(LSM_ATTR_CURRENT, ctx, 1, 0)); > + > + free(ctx); > +} > + > +TEST(flags_zero_lsm_set_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + struct lsm_ctx *ctx = calloc(page_size, 1); > + size_t size = page_size; > + > + ASSERT_NE(NULL, ctx); > + if (attr_lsm_count()) { > + ASSERT_LE(1, lsm_get_self_attr(LSM_ATTR_CURRENT, ctx, &size, > + 0)); > + } > + ASSERT_EQ(-1, lsm_set_self_attr(LSM_ATTR_CURRENT, ctx, size, 1)); > + > + free(ctx); > +} > + > +TEST(flags_overset_lsm_set_self_attr) > +{ > + const long page_size = sysconf(_SC_PAGESIZE); > + char *ctx = calloc(page_size, 1); > + size_t size = page_size; > + struct lsm_ctx *tctx = (struct lsm_ctx *)ctx; > + > + ASSERT_NE(NULL, ctx); > + if (attr_lsm_count()) { > + ASSERT_LE(1, lsm_get_self_attr(LSM_ATTR_CURRENT, tctx, &size, > + 0)); > + } > + ASSERT_EQ(-1, lsm_set_self_attr(LSM_ATTR_CURRENT | LSM_ATTR_PREV, tctx, > + size, 0)); > + > + free(ctx); > +} > + > +TEST_HARNESS_MAIN > -- > 2.41.0 > >
