> From: deven.desai@xxxxxxxxxxxxxxxxxxx > [mailto:deven.desai@xxxxxxxxxxxxxxxxxxx] > From: Deven Bowers <deven.desai@xxxxxxxxxxxxxxxxxxx> > > Enables an IPE policy to be enforced from kernel start, enabling access > control based on trust from kernel startup. This is accomplished by > transforming an IPE policy indicated by CONFIG_IPE_BOOT_POLICY into a > c-string literal that is parsed at kernel startup as an unsigned policy. > > Signed-off-by: Deven Bowers <deven.desai@xxxxxxxxxxxxxxxxxxx> > --- > > Relevant changes since v6: > * Move patch 01/12 to [14/16] of the series > > --- > MAINTAINERS | 1 + > scripts/Makefile | 1 + > scripts/ipe/Makefile | 2 + > scripts/ipe/polgen/.gitignore | 1 + > scripts/ipe/polgen/Makefile | 6 ++ > scripts/ipe/polgen/polgen.c | 145 ++++++++++++++++++++++++++++++++++ > security/ipe/.gitignore | 1 + > security/ipe/Kconfig | 10 +++ > security/ipe/Makefile | 13 +++ > security/ipe/ctx.c | 18 +++++ > 10 files changed, 198 insertions(+) > create mode 100644 scripts/ipe/Makefile > create mode 100644 scripts/ipe/polgen/.gitignore > create mode 100644 scripts/ipe/polgen/Makefile > create mode 100644 scripts/ipe/polgen/polgen.c > create mode 100644 security/ipe/.gitignore > > diff --git a/MAINTAINERS b/MAINTAINERS > index f1e76f791d47..a84ca781199b 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -9283,6 +9283,7 @@ INTEGRITY POLICY ENFORCEMENT (IPE) > M: Deven Bowers <deven.desai@xxxxxxxxxxxxxxxxxxx> > M: Fan Wu <wufan@xxxxxxxxxxxxxxxxxxx> > S: Supported > +F: scripts/ipe/ > F: security/ipe/ > > INTEL 810/815 FRAMEBUFFER DRIVER > diff --git a/scripts/Makefile b/scripts/Makefile > index 9adb6d247818..a31da6d57a36 100644 > --- a/scripts/Makefile > +++ b/scripts/Makefile > @@ -41,6 +41,7 @@ targets += module.lds > subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins > subdir-$(CONFIG_MODVERSIONS) += genksyms > subdir-$(CONFIG_SECURITY_SELINUX) += selinux > +subdir-$(CONFIG_SECURITY_IPE) += ipe > > # Let clean descend into subdirs > subdir- += basic dtc gdb kconfig mod > diff --git a/scripts/ipe/Makefile b/scripts/ipe/Makefile > new file mode 100644 > index 000000000000..e87553fbb8d6 > --- /dev/null > +++ b/scripts/ipe/Makefile > @@ -0,0 +1,2 @@ > +# SPDX-License-Identifier: GPL-2.0-only > +subdir-y := polgen > diff --git a/scripts/ipe/polgen/.gitignore b/scripts/ipe/polgen/.gitignore > new file mode 100644 > index 000000000000..80f32f25d200 > --- /dev/null > +++ b/scripts/ipe/polgen/.gitignore > @@ -0,0 +1 @@ > +polgen > diff --git a/scripts/ipe/polgen/Makefile b/scripts/ipe/polgen/Makefile > new file mode 100644 > index 000000000000..066060c22b4a > --- /dev/null > +++ b/scripts/ipe/polgen/Makefile > @@ -0,0 +1,6 @@ > +# SPDX-License-Identifier: GPL-2.0 > +hostprogs-always-y := polgen > +HOST_EXTRACFLAGS += \ > + -I$(srctree)/include \ > + -I$(srctree)/include/uapi \ > + > diff --git a/scripts/ipe/polgen/polgen.c b/scripts/ipe/polgen/polgen.c > new file mode 100644 > index 000000000000..73cf13e743f7 > --- /dev/null > +++ b/scripts/ipe/polgen/polgen.c > @@ -0,0 +1,145 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) Microsoft Corporation. All rights reserved. > + */ > + > +#include <stdlib.h> > +#include <stddef.h> > +#include <stdio.h> > +#include <unistd.h> > +#include <errno.h> > + > +static void usage(const char *const name) > +{ > + printf("Usage: %s OutputFile (PolicyFile)\n", name); > + exit(EINVAL); > +} > + > +static int policy_to_buffer(const char *pathname, char **buffer, size_t *size) > +{ > + int rc = 0; > + FILE *fd; > + char *lbuf; > + size_t fsize; > + size_t read; > + > + fd = fopen(pathname, "r"); > + if (!fd) { > + rc = errno; > + goto out; > + } > + > + fseek(fd, 0, SEEK_END); > + fsize = ftell(fd); > + rewind(fd); > + > + lbuf = malloc(fsize); > + if (!lbuf) { > + rc = ENOMEM; > + goto out_close; > + } > + > + read = fread((void *)lbuf, sizeof(*lbuf), fsize, fd); > + if (read != fsize) { > + rc = -1; > + goto out_free; > + } > + > + *buffer = lbuf; > + *size = fsize; > + fclose(fd); > + > + return rc; > + > +out_free: > + free(lbuf); > +out_close: > + fclose(fd); > +out: > + return rc; > +} > + > +static int write_boot_policy(const char *pathname, const char *buf, size_t size) > +{ > + int rc = 0; > + FILE *fd; > + size_t i; > + > + fd = fopen(pathname, "w"); > + if (!fd) { > + rc = errno; > + goto err; > + } > + > + fprintf(fd, "/* This file is automatically generated."); > + fprintf(fd, " Do not edit. */\n"); > + fprintf(fd, "#include <stddef.h>\n"); > + fprintf(fd, "\nextern const char *const ipe_boot_policy;\n\n"); > + fprintf(fd, "const char *const ipe_boot_policy =\n"); > + > + if (!buf || size == 0) { > + fprintf(fd, "\tNULL;\n"); > + fclose(fd); > + return 0; > + } > + > + fprintf(fd, "\t\""); > + > + for (i = 0; i < size; ++i) { > + switch (buf[i]) { > + case '"': > + fprintf(fd, "\\\""); > + break; > + case '\'': > + fprintf(fd, "'"); > + break; > + case '\n': > + fprintf(fd, "\\n\"\n\t\""); > + break; > + case '\\': > + fprintf(fd, "\\\\"); > + break; > + case '\t': > + fprintf(fd, "\\t"); > + break; > + case '\?': > + fprintf(fd, "\\?"); > + break; > + default: > + fprintf(fd, "%c", buf[i]); > + } > + } > + fprintf(fd, "\";\n"); > + fclose(fd); > + > + return 0; > + > +err: > + if (fd) > + fclose(fd); > + return rc; > +} > + > +int main(int argc, const char *const argv[]) > +{ > + int rc = 0; > + size_t len = 0; > + char *policy = NULL; > + > + if (argc < 2) > + usage(argv[0]); > + > + if (argc > 2) { > + rc = policy_to_buffer(argv[2], &policy, &len); > + if (rc != 0) > + goto cleanup; > + } > + > + rc = write_boot_policy(argv[1], policy, len); > +cleanup: > + if (policy) > + free(policy); > + if (rc != 0) > + perror("An error occurred during policy conversion: "); > + return rc; > +} > diff --git a/security/ipe/.gitignore b/security/ipe/.gitignore > new file mode 100644 > index 000000000000..eca22ad5ed22 > --- /dev/null > +++ b/security/ipe/.gitignore > @@ -0,0 +1 @@ > +boot-policy.c > \ No newline at end of file > diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig > index fcf82a8152ec..39df680b67a2 100644 > --- a/security/ipe/Kconfig > +++ b/security/ipe/Kconfig > @@ -20,6 +20,16 @@ menuconfig SECURITY_IPE > > if SECURITY_IPE > > +config IPE_BOOT_POLICY > + string "Integrity policy to apply on system startup" > + help > + This option specifies a filepath to a IPE policy that is compiled > + into the kernel. This policy will be enforced until a policy update > + is deployed via the $securityfs/ipe/policies/$policy_name/active > + interface. > + > + If unsure, leave blank. > + > choice > prompt "Hash algorithm used in auditing policies" > default IPE_AUDIT_HASH_SHA1 > diff --git a/security/ipe/Makefile b/security/ipe/Makefile > index 1e7b2d7fcd9e..89fec670f954 100644 > --- a/security/ipe/Makefile > +++ b/security/ipe/Makefile > @@ -7,7 +7,18 @@ > > ccflags-y := -I$(srctree)/security/ipe/modules > > +quiet_cmd_polgen = IPE_POL $(2) > + cmd_polgen = scripts/ipe/polgen/polgen security/ipe/boot-policy.c $(2) > + > +$(eval $(call config_filename,IPE_BOOT_POLICY)) > + > +targets += boot-policy.c > + > +$(obj)/boot-policy.c: scripts/ipe/polgen/polgen > $(IPE_BOOT_POLICY_FILENAME) FORCE > + $(call if_changed,polgen,$(IPE_BOOT_POLICY_FILENAME)) > + > obj-$(CONFIG_SECURITY_IPE) += \ > + boot-policy.o \ > ctx.o \ > eval.o \ > fs.o \ > @@ -21,3 +32,5 @@ obj-$(CONFIG_SECURITY_IPE) += \ > policyfs.o \ > > obj-$(CONFIG_AUDIT) += audit.o > + > +clean-files := boot-policy.c \ > diff --git a/security/ipe/ctx.c b/security/ipe/ctx.c > index fc9b8e467bc9..879acf4ceac5 100644 > --- a/security/ipe/ctx.c > +++ b/security/ipe/ctx.c > @@ -15,6 +15,7 @@ > #include <linux/spinlock.h> > #include <linux/moduleparam.h> > > +extern const char *const ipe_boot_policy; > static bool success_audit; > static bool enforce = true; > > @@ -329,6 +330,7 @@ void ipe_put_ctx(struct ipe_context *ctx) > int __init ipe_init_ctx(void) > { > int rc = 0; > + struct ipe_policy *p = NULL; > struct ipe_context *lns = NULL; > > lns = create_ctx(); > @@ -342,10 +344,26 @@ int __init ipe_init_ctx(void) > WRITE_ONCE(lns->enforce, enforce); > spin_unlock(&lns->lock); > > + if (ipe_boot_policy) { > + p = ipe_new_policy(ipe_boot_policy, strlen(ipe_boot_policy), > + NULL, 0); > + if (IS_ERR(p)) { > + rc = PTR_ERR(lns); This should be: rc = PTR_ERR(p); > + goto err; > + } > + > + ipe_add_policy(lns, p); > + rc = ipe_set_active_pol(p); > + if (!rc) Here you need to set a non-zero value, so that ipe_init() does not enable the LSM. I would set to 1 a new global variable, like ipe_lsm_enabled, in ipe_init() just before security_add_hooks(). Then, I would add a check of this variable in ipe_init_securityfs() to avoid the kernel panic. Roberto HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Zhong Ronghua > + goto err; > + } > + > rcu_assign_pointer(*ipe_tsk_ctx(current), lns); > + ipe_put_policy(p); > > return 0; > err: > + ipe_put_policy(p); > ipe_put_ctx(lns); > return rc; > } > -- > 2.33.0
