> From: Roberto Sassu [mailto:roberto.sassu@xxxxxxxxxx] > Sent: Wednesday, November 3, 2021 5:43 PM > > 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. Actually you probably should just check that rc is not zero and goto err. Roberto HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Zhong Ronghua > 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
