| Message ID | 1634151995-16266-15-git-send-email-deven.desai@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Integrity Policy Enforcement (IPE) | expand |
> From: deven.desai@linux.microsoft.com > [mailto:deven.desai@linux.microsoft.com] > From: Deven Bowers <deven.desai@linux.microsoft.com> > > 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@linux.microsoft.com> > --- > > 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@linux.microsoft.com> > M: Fan Wu <wufan@linux.microsoft.com> > 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
> From: Roberto Sassu [mailto:roberto.sassu@huawei.com] > Sent: Wednesday, November 3, 2021 5:43 PM > > From: deven.desai@linux.microsoft.com > > [mailto:deven.desai@linux.microsoft.com] > > From: Deven Bowers <deven.desai@linux.microsoft.com> > > > > 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@linux.microsoft.com> > > --- > > > > 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@linux.microsoft.com> > > M: Fan Wu <wufan@linux.microsoft.com> > > 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
On 11/3/2021 9:53 AM, Roberto Sassu wrote: >> From: Roberto Sassu [mailto:roberto.sassu@huawei.com] >> Sent: Wednesday, November 3, 2021 5:43 PM >>> From: deven.desai@linux.microsoft.com >>> [mailto:deven.desai@linux.microsoft.com] >>> From: Deven Bowers <deven.desai@linux.microsoft.com> >>> >>> 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@linux.microsoft.com> >>> --- >>> >>> 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@linux.microsoft.com> >>> M: Fan Wu <wufan@linux.microsoft.com> >>> 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 > Yeah, I actually noticed these two mistakes myself fairly recently. Changes will be applied in v8. > >> 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. That's my plan. -Deven
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@linux.microsoft.com> M: Fan Wu <wufan@linux.microsoft.com> 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); + goto err; + } + + ipe_add_policy(lns, p); + rc = ipe_set_active_pol(p); + if (!rc) + 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; }