| Message ID | 1706654228-17180-16-git-send-email-wufan@linux.microsoft.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | Integrity Policy Enforcement LSM (IPE) | expand |
On Jan 30, 2024 Fan Wu <wufan@linux.microsoft.com> wrote: > > Allows author of IPE policy to indicate trust for a singular dm-verity > volume, identified by roothash, through "dmverity_roothash" and all > signed dm-verity volumes, through "dmverity_signature". > > Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> > Signed-off-by: Fan Wu <wufan@linux.microsoft.com> > --- > v2: > + No Changes > > v3: > + No changes > > v4: > + No changes > > v5: > + No changes > > v6: > + Fix an improper cleanup that can result in > a leak > > v7: > + Squash patch 08/12, 10/12 to [11/16] > > v8: > + Undo squash of 08/12, 10/12 - separating drivers/md/ from security/ > & block/ > + Use common-audit function for dmverity_signature. > + Change implementation for storing the dm-verity digest to use the > newly introduced dm_verity_digest structure introduced in patch > 14/20. > > v9: > + Adapt to the new parser > > v10: > + Select the Kconfig when all dependencies are enabled > > v11: > + No changes > > v12: > + Refactor to use struct digest_info* instead of void* > + Correct audit format > --- > security/ipe/Kconfig | 18 ++++++ > security/ipe/Makefile | 1 + > security/ipe/audit.c | 37 ++++++++++- > security/ipe/digest.c | 120 +++++++++++++++++++++++++++++++++++ > security/ipe/digest.h | 26 ++++++++ > security/ipe/eval.c | 90 +++++++++++++++++++++++++- > security/ipe/eval.h | 10 +++ > security/ipe/hooks.c | 67 +++++++++++++++++++ > security/ipe/hooks.h | 8 +++ > security/ipe/ipe.c | 15 +++++ > security/ipe/ipe.h | 4 ++ > security/ipe/policy.h | 3 + > security/ipe/policy_parser.c | 26 +++++++- > 13 files changed, 421 insertions(+), 4 deletions(-) > create mode 100644 security/ipe/digest.c > create mode 100644 security/ipe/digest.h > > diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig > index ac4d558e69d5..7afb1ce0cb99 100644 > --- a/security/ipe/Kconfig > +++ b/security/ipe/Kconfig > @@ -8,6 +8,7 @@ menuconfig SECURITY_IPE > depends on SECURITY && SECURITYFS && AUDIT && AUDITSYSCALL > select PKCS7_MESSAGE_PARSER > select SYSTEM_DATA_VERIFICATION > + select IPE_PROP_DM_VERITY if DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG > help > This option enables the Integrity Policy Enforcement LSM > allowing users to define a policy to enforce a trust-based access > @@ -15,3 +16,20 @@ menuconfig SECURITY_IPE > admins to reconfigure trust requirements on the fly. > > If unsure, answer N. > + > +if SECURITY_IPE > +menu "IPE Trust Providers" > + > +config IPE_PROP_DM_VERITY > + bool "Enable support for dm-verity volumes" > + depends on DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG > + help > + This option enables the properties 'dmverity_signature' and > + 'dmverity_roothash' in IPE policy. These properties evaluates > + to TRUE when a file is evaluated against a dm-verity volume > + that was mounted with a signed root-hash or the volume's > + root hash matches the supplied value in the policy. > + > +endmenu > + > +endif > diff --git a/security/ipe/Makefile b/security/ipe/Makefile > index 2279eaa3cea3..66de53687d11 100644 > --- a/security/ipe/Makefile > +++ b/security/ipe/Makefile > @@ -6,6 +6,7 @@ > # > > obj-$(CONFIG_SECURITY_IPE) += \ > + digest.o \ > eval.o \ > hooks.o \ > fs.o \ > diff --git a/security/ipe/audit.c b/security/ipe/audit.c > index ed390d32c641..a4ad8e888df0 100644 > --- a/security/ipe/audit.c > +++ b/security/ipe/audit.c > @@ -13,6 +13,7 @@ > #include "hooks.h" > #include "policy.h" > #include "audit.h" > +#include "digest.h" > > #define ACTSTR(x) ((x) == IPE_ACTION_ALLOW ? "ALLOW" : "DENY") > > @@ -54,8 +55,30 @@ static const char *const audit_prop_names[__IPE_PROP_MAX] = { > "boot_verified=FALSE", > "boot_verified=TRUE", > #endif /* CONFIG_BLK_DEV_INITRD */ > +#ifdef CONFIG_IPE_PROP_DM_VERITY > + "dmverity_roothash=", > + "dmverity_signature=FALSE", > + "dmverity_signature=TRUE", > +#endif /* CONFIG_IPE_PROP_DM_VERITY */ > }; > > +#ifdef CONFIG_IPE_PROP_DM_VERITY > +/** > + * audit_dmv_roothash - audit a roothash of a dmverity volume. > + * @ab: Supplies a pointer to the audit_buffer to append to. > + * @rh: Supplies a pointer to the digest structure. > + */ > +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) > +{ > + audit_log_format(ab, "%s", audit_prop_names[IPE_PROP_DMV_ROOTHASH]); > + ipe_digest_audit(ab, rh); > +} > +#else > +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) > +{ > +} > +#endif /* CONFIG_IPE_PROP_DM_VERITY */ I talked about this back in my review of the v11 patchset and I'm guessing you may have missed it ... the problem with the above code is that the fields in an audit record should remain constant, even if there is no data for that particular field. In cases where there is no data to record for a given field, a "?" should be used as the field's value, for example: dmverify_roothash=? My guess is that you would want to do something like this: #else /* !CONFIG_IPE_PROP_DM_VERITY */ static void audit_dmv_roothash(...) { audit_log_format(ab, "%s=?", audit_prop_names[...]); } #endif /* CONFIG_IPE_PROP_DM_VERITY */ -- paul-moore.com
On 2/3/2024 2:25 PM, Paul Moore wrote: > On Jan 30, 2024 Fan Wu <wufan@linux.microsoft.com> wrote: >> >> Allows author of IPE policy to indicate trust for a singular dm-verity >> volume, identified by roothash, through "dmverity_roothash" and all >> signed dm-verity volumes, through "dmverity_signature". >> >> Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> >> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> >> --- >> v2: >> + No Changes >> >> v3: >> + No changes >> >> v4: >> + No changes >> >> v5: >> + No changes >> >> v6: >> + Fix an improper cleanup that can result in >> a leak >> >> v7: >> + Squash patch 08/12, 10/12 to [11/16] >> >> v8: >> + Undo squash of 08/12, 10/12 - separating drivers/md/ from security/ >> & block/ >> + Use common-audit function for dmverity_signature. >> + Change implementation for storing the dm-verity digest to use the >> newly introduced dm_verity_digest structure introduced in patch >> 14/20. >> >> v9: >> + Adapt to the new parser >> >> v10: >> + Select the Kconfig when all dependencies are enabled >> >> v11: >> + No changes >> >> v12: >> + Refactor to use struct digest_info* instead of void* >> + Correct audit format >> --- >> security/ipe/Kconfig | 18 ++++++ >> security/ipe/Makefile | 1 + >> security/ipe/audit.c | 37 ++++++++++- >> security/ipe/digest.c | 120 +++++++++++++++++++++++++++++++++++ >> security/ipe/digest.h | 26 ++++++++ >> security/ipe/eval.c | 90 +++++++++++++++++++++++++- >> security/ipe/eval.h | 10 +++ >> security/ipe/hooks.c | 67 +++++++++++++++++++ >> security/ipe/hooks.h | 8 +++ >> security/ipe/ipe.c | 15 +++++ >> security/ipe/ipe.h | 4 ++ >> security/ipe/policy.h | 3 + >> security/ipe/policy_parser.c | 26 +++++++- >> 13 files changed, 421 insertions(+), 4 deletions(-) >> create mode 100644 security/ipe/digest.c >> create mode 100644 security/ipe/digest.h >> >> diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig >> index ac4d558e69d5..7afb1ce0cb99 100644 >> --- a/security/ipe/Kconfig >> +++ b/security/ipe/Kconfig >> @@ -8,6 +8,7 @@ menuconfig SECURITY_IPE >> depends on SECURITY && SECURITYFS && AUDIT && AUDITSYSCALL >> select PKCS7_MESSAGE_PARSER >> select SYSTEM_DATA_VERIFICATION >> + select IPE_PROP_DM_VERITY if DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG >> help >> This option enables the Integrity Policy Enforcement LSM >> allowing users to define a policy to enforce a trust-based access >> @@ -15,3 +16,20 @@ menuconfig SECURITY_IPE >> admins to reconfigure trust requirements on the fly. >> >> If unsure, answer N. >> + >> +if SECURITY_IPE >> +menu "IPE Trust Providers" >> + >> +config IPE_PROP_DM_VERITY >> + bool "Enable support for dm-verity volumes" >> + depends on DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG >> + help >> + This option enables the properties 'dmverity_signature' and >> + 'dmverity_roothash' in IPE policy. These properties evaluates >> + to TRUE when a file is evaluated against a dm-verity volume >> + that was mounted with a signed root-hash or the volume's >> + root hash matches the supplied value in the policy. >> + >> +endmenu >> + >> +endif >> diff --git a/security/ipe/Makefile b/security/ipe/Makefile >> index 2279eaa3cea3..66de53687d11 100644 >> --- a/security/ipe/Makefile >> +++ b/security/ipe/Makefile >> @@ -6,6 +6,7 @@ >> # >> >> obj-$(CONFIG_SECURITY_IPE) += \ >> + digest.o \ >> eval.o \ >> hooks.o \ >> fs.o \ >> diff --git a/security/ipe/audit.c b/security/ipe/audit.c >> index ed390d32c641..a4ad8e888df0 100644 >> --- a/security/ipe/audit.c >> +++ b/security/ipe/audit.c >> @@ -13,6 +13,7 @@ >> #include "hooks.h" >> #include "policy.h" >> #include "audit.h" >> +#include "digest.h" >> >> #define ACTSTR(x) ((x) == IPE_ACTION_ALLOW ? "ALLOW" : "DENY") >> >> @@ -54,8 +55,30 @@ static const char *const audit_prop_names[__IPE_PROP_MAX] = { >> "boot_verified=FALSE", >> "boot_verified=TRUE", >> #endif /* CONFIG_BLK_DEV_INITRD */ >> +#ifdef CONFIG_IPE_PROP_DM_VERITY >> + "dmverity_roothash=", >> + "dmverity_signature=FALSE", >> + "dmverity_signature=TRUE", >> +#endif /* CONFIG_IPE_PROP_DM_VERITY */ >> }; >> >> +#ifdef CONFIG_IPE_PROP_DM_VERITY >> +/** >> + * audit_dmv_roothash - audit a roothash of a dmverity volume. >> + * @ab: Supplies a pointer to the audit_buffer to append to. >> + * @rh: Supplies a pointer to the digest structure. >> + */ >> +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) >> +{ >> + audit_log_format(ab, "%s", audit_prop_names[IPE_PROP_DMV_ROOTHASH]); >> + ipe_digest_audit(ab, rh); >> +} >> +#else >> +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) >> +{ >> +} >> +#endif /* CONFIG_IPE_PROP_DM_VERITY */ > > I talked about this back in my review of the v11 patchset and I'm > guessing you may have missed it ... the problem with the above code is > that the fields in an audit record should remain constant, even if > there is no data for that particular field. In cases where there is no > data to record for a given field, a "?" should be used as the field's > value, for example: > > dmverify_roothash=? > > My guess is that you would want to do something like this: > > #else /* !CONFIG_IPE_PROP_DM_VERITY */ > static void audit_dmv_roothash(...) > { > audit_log_format(ab, "%s=?", audit_prop_names[...]); > } > #endif /* CONFIG_IPE_PROP_DM_VERITY */ > > -- > paul-moore.com These code are used for auditing a policy rule, which the parser will guarantee the property will always have a valid value. The comments might be misleading which sounds like it's auditing a file's state. I will correct them. Also as we previously discussed, the policy grammar shouldn't depend on any kernel switch so these preprocessor statement will be removed. However, as an audit record should remain constant, I guess we should do some special treatment to anonymous files? Like audit record for them should include "path=? dev=? ino=?" Thanks, Fan
On Mon, Feb 5, 2024 at 6:11 PM Fan Wu <wufan@linux.microsoft.com> wrote: > On 2/3/2024 2:25 PM, Paul Moore wrote: > > On Jan 30, 2024 Fan Wu <wufan@linux.microsoft.com> wrote: > >> > >> Allows author of IPE policy to indicate trust for a singular dm-verity > >> volume, identified by roothash, through "dmverity_roothash" and all > >> signed dm-verity volumes, through "dmverity_signature". > >> > >> Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> > >> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> > >> --- > >> v2: > >> + No Changes > >> > >> v3: > >> + No changes > >> > >> v4: > >> + No changes > >> > >> v5: > >> + No changes > >> > >> v6: > >> + Fix an improper cleanup that can result in > >> a leak > >> > >> v7: > >> + Squash patch 08/12, 10/12 to [11/16] > >> > >> v8: > >> + Undo squash of 08/12, 10/12 - separating drivers/md/ from security/ > >> & block/ > >> + Use common-audit function for dmverity_signature. > >> + Change implementation for storing the dm-verity digest to use the > >> newly introduced dm_verity_digest structure introduced in patch > >> 14/20. > >> > >> v9: > >> + Adapt to the new parser > >> > >> v10: > >> + Select the Kconfig when all dependencies are enabled > >> > >> v11: > >> + No changes > >> > >> v12: > >> + Refactor to use struct digest_info* instead of void* > >> + Correct audit format > >> --- > >> security/ipe/Kconfig | 18 ++++++ > >> security/ipe/Makefile | 1 + > >> security/ipe/audit.c | 37 ++++++++++- > >> security/ipe/digest.c | 120 +++++++++++++++++++++++++++++++++++ > >> security/ipe/digest.h | 26 ++++++++ > >> security/ipe/eval.c | 90 +++++++++++++++++++++++++- > >> security/ipe/eval.h | 10 +++ > >> security/ipe/hooks.c | 67 +++++++++++++++++++ > >> security/ipe/hooks.h | 8 +++ > >> security/ipe/ipe.c | 15 +++++ > >> security/ipe/ipe.h | 4 ++ > >> security/ipe/policy.h | 3 + > >> security/ipe/policy_parser.c | 26 +++++++- > >> 13 files changed, 421 insertions(+), 4 deletions(-) > >> create mode 100644 security/ipe/digest.c > >> create mode 100644 security/ipe/digest.h > >> > >> diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig > >> index ac4d558e69d5..7afb1ce0cb99 100644 > >> --- a/security/ipe/Kconfig > >> +++ b/security/ipe/Kconfig > >> @@ -8,6 +8,7 @@ menuconfig SECURITY_IPE > >> depends on SECURITY && SECURITYFS && AUDIT && AUDITSYSCALL > >> select PKCS7_MESSAGE_PARSER > >> select SYSTEM_DATA_VERIFICATION > >> + select IPE_PROP_DM_VERITY if DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG > >> help > >> This option enables the Integrity Policy Enforcement LSM > >> allowing users to define a policy to enforce a trust-based access > >> @@ -15,3 +16,20 @@ menuconfig SECURITY_IPE > >> admins to reconfigure trust requirements on the fly. > >> > >> If unsure, answer N. > >> + > >> +if SECURITY_IPE > >> +menu "IPE Trust Providers" > >> + > >> +config IPE_PROP_DM_VERITY > >> + bool "Enable support for dm-verity volumes" > >> + depends on DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG > >> + help > >> + This option enables the properties 'dmverity_signature' and > >> + 'dmverity_roothash' in IPE policy. These properties evaluates > >> + to TRUE when a file is evaluated against a dm-verity volume > >> + that was mounted with a signed root-hash or the volume's > >> + root hash matches the supplied value in the policy. > >> + > >> +endmenu > >> + > >> +endif > >> diff --git a/security/ipe/Makefile b/security/ipe/Makefile > >> index 2279eaa3cea3..66de53687d11 100644 > >> --- a/security/ipe/Makefile > >> +++ b/security/ipe/Makefile > >> @@ -6,6 +6,7 @@ > >> # > >> > >> obj-$(CONFIG_SECURITY_IPE) += \ > >> + digest.o \ > >> eval.o \ > >> hooks.o \ > >> fs.o \ > >> diff --git a/security/ipe/audit.c b/security/ipe/audit.c > >> index ed390d32c641..a4ad8e888df0 100644 > >> --- a/security/ipe/audit.c > >> +++ b/security/ipe/audit.c > >> @@ -13,6 +13,7 @@ > >> #include "hooks.h" > >> #include "policy.h" > >> #include "audit.h" > >> +#include "digest.h" > >> > >> #define ACTSTR(x) ((x) == IPE_ACTION_ALLOW ? "ALLOW" : "DENY") > >> > >> @@ -54,8 +55,30 @@ static const char *const audit_prop_names[__IPE_PROP_MAX] = { > >> "boot_verified=FALSE", > >> "boot_verified=TRUE", > >> #endif /* CONFIG_BLK_DEV_INITRD */ > >> +#ifdef CONFIG_IPE_PROP_DM_VERITY > >> + "dmverity_roothash=", > >> + "dmverity_signature=FALSE", > >> + "dmverity_signature=TRUE", > >> +#endif /* CONFIG_IPE_PROP_DM_VERITY */ > >> }; > >> > >> +#ifdef CONFIG_IPE_PROP_DM_VERITY > >> +/** > >> + * audit_dmv_roothash - audit a roothash of a dmverity volume. > >> + * @ab: Supplies a pointer to the audit_buffer to append to. > >> + * @rh: Supplies a pointer to the digest structure. > >> + */ > >> +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) > >> +{ > >> + audit_log_format(ab, "%s", audit_prop_names[IPE_PROP_DMV_ROOTHASH]); > >> + ipe_digest_audit(ab, rh); > >> +} > >> +#else > >> +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) > >> +{ > >> +} > >> +#endif /* CONFIG_IPE_PROP_DM_VERITY */ > > > > I talked about this back in my review of the v11 patchset and I'm > > guessing you may have missed it ... the problem with the above code is > > that the fields in an audit record should remain constant, even if > > there is no data for that particular field. In cases where there is no > > data to record for a given field, a "?" should be used as the field's > > value, for example: > > > > dmverify_roothash=? > > > > My guess is that you would want to do something like this: > > > > #else /* !CONFIG_IPE_PROP_DM_VERITY */ > > static void audit_dmv_roothash(...) > > { > > audit_log_format(ab, "%s=?", audit_prop_names[...]); > > } > > #endif /* CONFIG_IPE_PROP_DM_VERITY */ > > > > -- > > paul-moore.com > > These code are used for auditing a policy rule, which the parser will > guarantee the property will always have a valid value. The comments > might be misleading which sounds like it's auditing a file's state. I > will correct them. > > Also as we previously discussed, the policy grammar shouldn't depend on > any kernel switch so these preprocessor statement will be removed. > > However, as an audit record should remain constant, I guess we should do > some special treatment to anonymous files? Like audit record for them > should include "path=? dev=? ino=?" Yes, if the record type includes those fields just once, the record type should *always* include those fields.
diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig index ac4d558e69d5..7afb1ce0cb99 100644 --- a/security/ipe/Kconfig +++ b/security/ipe/Kconfig @@ -8,6 +8,7 @@ menuconfig SECURITY_IPE depends on SECURITY && SECURITYFS && AUDIT && AUDITSYSCALL select PKCS7_MESSAGE_PARSER select SYSTEM_DATA_VERIFICATION + select IPE_PROP_DM_VERITY if DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG help This option enables the Integrity Policy Enforcement LSM allowing users to define a policy to enforce a trust-based access @@ -15,3 +16,20 @@ menuconfig SECURITY_IPE admins to reconfigure trust requirements on the fly. If unsure, answer N. + +if SECURITY_IPE +menu "IPE Trust Providers" + +config IPE_PROP_DM_VERITY + bool "Enable support for dm-verity volumes" + depends on DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG + help + This option enables the properties 'dmverity_signature' and + 'dmverity_roothash' in IPE policy. These properties evaluates + to TRUE when a file is evaluated against a dm-verity volume + that was mounted with a signed root-hash or the volume's + root hash matches the supplied value in the policy. + +endmenu + +endif diff --git a/security/ipe/Makefile b/security/ipe/Makefile index 2279eaa3cea3..66de53687d11 100644 --- a/security/ipe/Makefile +++ b/security/ipe/Makefile @@ -6,6 +6,7 @@ # obj-$(CONFIG_SECURITY_IPE) += \ + digest.o \ eval.o \ hooks.o \ fs.o \ diff --git a/security/ipe/audit.c b/security/ipe/audit.c index ed390d32c641..a4ad8e888df0 100644 --- a/security/ipe/audit.c +++ b/security/ipe/audit.c @@ -13,6 +13,7 @@ #include "hooks.h" #include "policy.h" #include "audit.h" +#include "digest.h" #define ACTSTR(x) ((x) == IPE_ACTION_ALLOW ? "ALLOW" : "DENY") @@ -54,8 +55,30 @@ static const char *const audit_prop_names[__IPE_PROP_MAX] = { "boot_verified=FALSE", "boot_verified=TRUE", #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY + "dmverity_roothash=", + "dmverity_signature=FALSE", + "dmverity_signature=TRUE", +#endif /* CONFIG_IPE_PROP_DM_VERITY */ }; +#ifdef CONFIG_IPE_PROP_DM_VERITY +/** + * audit_dmv_roothash - audit a roothash of a dmverity volume. + * @ab: Supplies a pointer to the audit_buffer to append to. + * @rh: Supplies a pointer to the digest structure. + */ +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) +{ + audit_log_format(ab, "%s", audit_prop_names[IPE_PROP_DMV_ROOTHASH]); + ipe_digest_audit(ab, rh); +} +#else +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) +{ +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + /** * audit_rule - audit an IPE policy rule approximation. * @ab: Supplies a pointer to the audit_buffer to append to. @@ -67,8 +90,18 @@ static void audit_rule(struct audit_buffer *ab, const struct ipe_rule *r) audit_log_format(ab, " rule=\"%s ", audit_op_names[r->op]); - list_for_each_entry(ptr, &r->props, next) - audit_log_format(ab, "%s ", audit_prop_names[ptr->type]); + list_for_each_entry(ptr, &r->props, next) { + switch (ptr->type) { + case IPE_PROP_DMV_ROOTHASH: + audit_dmv_roothash(ab, ptr->value); + break; + default: + audit_log_format(ab, "%s", audit_prop_names[ptr->type]); + break; + } + + audit_log_format(ab, " "); + } audit_log_format(ab, "action=%s\"", ACTSTR(r->action)); } diff --git a/security/ipe/digest.c b/security/ipe/digest.c new file mode 100644 index 000000000000..f6fde0b1fe74 --- /dev/null +++ b/security/ipe/digest.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) Microsoft Corporation. All rights reserved. + */ + +#include "digest.h" + +/** + * ipe_digest_parse - parse a digest in IPE's policy. + * @valstr: Supplies the string parsed from the policy. + * + * Digests in IPE are defined in a standard way: + * <alg_name>:<hex> + * + * Use this function to create a property to parse the digest + * consistently. The parsed digest will be saved in @value in IPE's + * policy. + * + * Return: The parsed digest_info structure. + */ +struct digest_info *ipe_digest_parse(const char *valstr) +{ + char *sep, *raw_digest; + size_t raw_digest_len; + int rc = 0; + char *alg = NULL; + u8 *digest = NULL; + struct digest_info *info = NULL; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return ERR_PTR(-ENOMEM); + + sep = strchr(valstr, ':'); + if (!sep) { + rc = -EBADMSG; + goto err; + } + + alg = kstrndup(valstr, sep - valstr, GFP_KERNEL); + if (!alg) { + rc = -ENOMEM; + goto err; + } + + raw_digest = sep + 1; + raw_digest_len = strlen(raw_digest); + + info->digest_len = (raw_digest_len + 1) / 2; + digest = kzalloc(info->digest_len, GFP_KERNEL); + if (!digest) { + rc = -ENOMEM; + goto err; + } + + rc = hex2bin(digest, raw_digest, info->digest_len); + if (rc < 0) { + rc = -EINVAL; + goto err; + } + + info->alg = alg; + info->digest = digest; + return info; + +err: + kfree(alg); + kfree(digest); + kfree(info); + return ERR_PTR(rc); +} + +/** + * ipe_digest_eval - evaluate an IPE digest against another digest. + * @expected: Supplies the policy-provided digest value. + * @digest: Supplies the digest to compare against the policy digest value. + * + * Return: + * * true - digests match + * * false - digests do not match + */ +bool ipe_digest_eval(const struct digest_info *expected, + const struct digest_info *digest) +{ + return (expected->digest_len == digest->digest_len) && + (!strcmp(expected->alg, digest->alg)) && + (!memcmp(expected->digest, digest->digest, expected->digest_len)); +} + +/** + * ipe_digest_free - free an IPE digest. + * @info: Supplies a pointer the policy-provided digest to free. + */ +void ipe_digest_free(struct digest_info *info) +{ + if (IS_ERR_OR_NULL(info)) + return; + + kfree(info->alg); + kfree(info->digest); + kfree(info); +} + +/** + * ipe_digest_audit - audit a digest that was sourced from IPE's policy. + * @ab: Supplies the audit_buffer to append the formatted result. + * @info: Supplies a pointer to source the audit record from. + * + * Digests in IPE are defined in a standard way: + * <alg_name>:<hex> + * + * Use this function to create a property to audit the digest + * consistently. + */ +void ipe_digest_audit(struct audit_buffer *ab, const struct digest_info *info) +{ + audit_log_untrustedstring(ab, info->alg); + audit_log_format(ab, ":"); + audit_log_n_hex(ab, info->digest, info->digest_len); +} diff --git a/security/ipe/digest.h b/security/ipe/digest.h new file mode 100644 index 000000000000..13fa67071805 --- /dev/null +++ b/security/ipe/digest.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_DIGEST_H +#define _IPE_DIGEST_H + +#include <linux/types.h> +#include <linux/audit.h> + +#include "policy.h" + +struct digest_info { + const char *alg; + const u8 *digest; + size_t digest_len; +}; + +struct digest_info *ipe_digest_parse(const char *valstr); +void ipe_digest_free(struct digest_info *digest_info); +void ipe_digest_audit(struct audit_buffer *ab, const struct digest_info *val); +bool ipe_digest_eval(const struct digest_info *expected, + const struct digest_info *digest); + +#endif /* _IPE_DIGEST_H */ diff --git a/security/ipe/eval.c b/security/ipe/eval.c index 49338b35f126..4e0fd1dc5808 100644 --- a/security/ipe/eval.c +++ b/security/ipe/eval.c @@ -15,10 +15,12 @@ #include "eval.h" #include "policy.h" #include "audit.h" +#include "digest.h" struct ipe_policy __rcu *ipe_active_policy; bool success_audit; bool enforce = true; +#define INO_BLOCK_DEV(ino) ((ino)->i_sb->s_bdev) #define FILE_SUPERBLOCK(f) ((f)->f_path.mnt->mnt_sb) @@ -37,6 +39,22 @@ static void build_ipe_sb_ctx(struct ipe_eval_ctx *ctx, const struct file *const { } #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY +/** + * build_ipe_bdev_ctx - Build ipe_bdev field of an evaluation context. + * @ctx: Supplies a pointer to the context to be populated. + * @ino: Supplies the inode struct of the file triggered IPE event. + */ +static void build_ipe_bdev_ctx(struct ipe_eval_ctx *ctx, const struct inode *const ino) +{ + if (INO_BLOCK_DEV(ino)) + ctx->ipe_bdev = ipe_bdev(INO_BLOCK_DEV(ino)); +} +#else +static void build_ipe_bdev_ctx(struct ipe_eval_ctx *ctx, const struct inode *const ino) +{ +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ /** * build_eval_ctx - Build an evaluation context. @@ -54,8 +72,10 @@ void build_eval_ctx(struct ipe_eval_ctx *ctx, ctx->op = op; ctx->hook = hook; - if (file) + if (file) { build_ipe_sb_ctx(ctx, file); + build_ipe_bdev_ctx(ctx, d_real_inode(file->f_path.dentry)); + } } #ifdef CONFIG_BLK_DEV_INITRD @@ -96,6 +116,68 @@ static bool evaluate_boot_verified_false(const struct ipe_eval_ctx *const ctx) } #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY +/** + * evaluate_dmv_roothash - Evaluate @ctx against a dmv roothash property. + * @ctx: Supplies a pointer to the context being evaluated. + * @p: Supplies a pointer to the property being evaluated. + * + * Return: + * * true - The current @ctx match the @p + * * false - The current @ctx doesn't match the @p + */ +static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, + struct ipe_prop *p) +{ + return !!ctx->ipe_bdev && + !!ctx->ipe_bdev->root_hash && + ipe_digest_eval(p->value, + ctx->ipe_bdev->root_hash); +} + +/** + * evaluate_dmv_sig_false: Analyze @ctx against a dmv sig false property. + * @ctx: Supplies a pointer to the context being evaluated. + * + * Return: + * * true - The current @ctx match the property + * * false - The current @ctx doesn't match the property + */ +static bool evaluate_dmv_sig_false(const struct ipe_eval_ctx *const ctx) +{ + return !ctx->ipe_bdev || (!ctx->ipe_bdev->dm_verity_signed); +} + +/** + * evaluate_dmv_sig_true: Analyze @ctx against a dmv sig true property. + * @ctx: Supplies a pointer to the context being evaluated. + * + * Return: + * * true - The current @ctx match the property + * * false - The current @ctx doesn't match the property + */ +static bool evaluate_dmv_sig_true(const struct ipe_eval_ctx *const ctx) +{ + return !evaluate_dmv_sig_false(ctx); +} +#else +static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, + struct ipe_prop *p) +{ + return false; +} + +static bool evaluate_dmv_sig_false(const struct ipe_eval_ctx *const ctx) +{ + return false; +} + +static bool evaluate_dmv_sig_true(const struct ipe_eval_ctx *const ctx) +{ + return false; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + /** * evaluate_property - Analyze @ctx against a property. * @ctx: Supplies a pointer to the context to be evaluated. @@ -113,6 +195,12 @@ static bool evaluate_property(const struct ipe_eval_ctx *const ctx, return evaluate_boot_verified_false(ctx); case IPE_PROP_BOOT_VERIFIED_TRUE: return evaluate_boot_verified_true(ctx); + case IPE_PROP_DMV_ROOTHASH: + return evaluate_dmv_roothash(ctx, p); + case IPE_PROP_DMV_SIG_FALSE: + return evaluate_dmv_sig_false(ctx); + case IPE_PROP_DMV_SIG_TRUE: + return evaluate_dmv_sig_true(ctx); default: return false; } diff --git a/security/ipe/eval.h b/security/ipe/eval.h index 84adf1a0e514..2c997d188508 100644 --- a/security/ipe/eval.h +++ b/security/ipe/eval.h @@ -24,6 +24,13 @@ struct ipe_sb { }; #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev { + bool dm_verity_signed; + struct digest_info *root_hash; +}; +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + struct ipe_eval_ctx { enum ipe_op_type op; enum ipe_hook_type hook; @@ -32,6 +39,9 @@ struct ipe_eval_ctx { #ifdef CONFIG_BLK_DEV_INITRD bool from_initramfs; #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY + const struct ipe_bdev *ipe_bdev; +#endif /* CONFIG_IPE_PROP_DM_VERITY */ }; enum ipe_match { diff --git a/security/ipe/hooks.c b/security/ipe/hooks.c index ab762865a671..50c5324dcd92 100644 --- a/security/ipe/hooks.c +++ b/security/ipe/hooks.c @@ -8,10 +8,14 @@ #include <linux/types.h> #include <linux/binfmts.h> #include <linux/mman.h> +#include <linux/blk_types.h> +#include <linux/dm-verity.h> +#include <crypto/hash_info.h> #include "ipe.h" #include "hooks.h" #include "eval.h" +#include "digest.h" /** * ipe_bprm_check_security - ipe security hook function for bprm check. @@ -189,3 +193,66 @@ void ipe_unpack_initramfs(void) ipe_sb(current->fs->root.mnt->mnt_sb)->is_initramfs = true; } #endif /* CONFIG_BLK_DEV_INITRD */ + +#ifdef CONFIG_IPE_PROP_DM_VERITY +/** + * ipe_bdev_free_security - free IPE's LSM blob of block_devices. + * @bdev: Supplies a pointer to a block_device that contains the structure + * to free. + */ +void ipe_bdev_free_security(struct block_device *bdev) +{ + struct ipe_bdev *blob = ipe_bdev(bdev); + + ipe_digest_free(blob->root_hash); +} + +/** + * ipe_bdev_setsecurity - save data from a bdev to IPE's LSM blob. + * @bdev: Supplies a pointer to a block_device that contains the LSM blob. + * @key: Supplies the string key that uniquely identifies the value. + * @value: Supplies the value to store. + * @len: The length of @value. + */ +int ipe_bdev_setsecurity(struct block_device *bdev, const char *key, + const void *value, size_t len) +{ + struct ipe_bdev *blob = ipe_bdev(bdev); + + if (!strcmp(key, DM_VERITY_ROOTHASH_SEC_NAME)) { + const struct dm_verity_digest *digest = value; + struct digest_info *info = NULL; + u8 *raw_digest = NULL; + char *alg = NULL; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + raw_digest = kmemdup(digest->digest, digest->digest_len, + GFP_KERNEL); + if (!raw_digest) + goto err; + + alg = kstrdup(digest->alg, GFP_KERNEL); + if (!alg) + goto err; + + info->alg = alg; + info->digest = raw_digest; + info->digest_len = digest->digest_len; + blob->root_hash = info; + return 0; +err: + kfree(info); + kfree(raw_digest); + kfree(alg); + return -ENOMEM; + } else if (!strcmp(key, DM_VERITY_SIGNATURE_SEC_NAME)) { + blob->dm_verity_signed = true; + return 0; + } + + return -EOPNOTSUPP; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ diff --git a/security/ipe/hooks.h b/security/ipe/hooks.h index 55fc0e35c13d..e114d633dcb4 100644 --- a/security/ipe/hooks.h +++ b/security/ipe/hooks.h @@ -8,6 +8,7 @@ #include <linux/fs.h> #include <linux/binfmts.h> #include <linux/security.h> +#include <linux/blk_types.h> enum ipe_hook_type { IPE_HOOK_BPRM_CHECK = 0, @@ -37,4 +38,11 @@ int ipe_kernel_load_data(enum kernel_load_data_id id, bool contents); void ipe_unpack_initramfs(void); #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY +void ipe_bdev_free_security(struct block_device *bdev); + +int ipe_bdev_setsecurity(struct block_device *bdev, const char *key, + const void *value, size_t len); +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + #endif /* _IPE_HOOKS_H */ diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c index 034ee8cd6802..27a76aeabf1d 100644 --- a/security/ipe/ipe.c +++ b/security/ipe/ipe.c @@ -7,6 +7,7 @@ #include "ipe.h" #include "eval.h" #include "hooks.h" +#include "eval.h" bool ipe_enabled; @@ -14,6 +15,9 @@ static struct lsm_blob_sizes ipe_blobs __ro_after_init = { #ifdef CONFIG_BLK_DEV_INITRD .lbs_superblock = sizeof(struct ipe_sb), #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY + .lbs_bdev = sizeof(struct ipe_bdev), +#endif /* CONFIG_IPE_PROP_DM_VERITY */ }; static const struct lsm_id ipe_lsmid = { @@ -28,6 +32,13 @@ struct ipe_sb *ipe_sb(const struct super_block *sb) } #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev *ipe_bdev(struct block_device *b) +{ + return b->security + ipe_blobs.lbs_bdev; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + static struct security_hook_list ipe_hooks[] __ro_after_init = { LSM_HOOK_INIT(bprm_check_security, ipe_bprm_check_security), LSM_HOOK_INIT(mmap_file, ipe_mmap_file), @@ -37,6 +48,10 @@ static struct security_hook_list ipe_hooks[] __ro_after_init = { #ifdef CONFIG_BLK_DEV_INITRD LSM_HOOK_INIT(unpack_initramfs_security, ipe_unpack_initramfs), #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY + LSM_HOOK_INIT(bdev_free_security, ipe_bdev_free_security), + LSM_HOOK_INIT(bdev_setsecurity, ipe_bdev_setsecurity), +#endif /* CONFIG_IPE_PROP_DM_VERITY */ }; /** diff --git a/security/ipe/ipe.h b/security/ipe/ipe.h index 1862c710dab8..03dab0dec54a 100644 --- a/security/ipe/ipe.h +++ b/security/ipe/ipe.h @@ -18,4 +18,8 @@ struct ipe_sb *ipe_sb(const struct super_block *sb); extern bool ipe_enabled; +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev *ipe_bdev(struct block_device *b); +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + #endif /* _IPE_H */ diff --git a/security/ipe/policy.h b/security/ipe/policy.h index 060ffdbc62d6..fa59037c3fa4 100644 --- a/security/ipe/policy.h +++ b/security/ipe/policy.h @@ -33,6 +33,9 @@ enum ipe_action_type { enum ipe_prop_type { IPE_PROP_BOOT_VERIFIED_FALSE, IPE_PROP_BOOT_VERIFIED_TRUE, + IPE_PROP_DMV_ROOTHASH, + IPE_PROP_DMV_SIG_FALSE, + IPE_PROP_DMV_SIG_TRUE, __IPE_PROP_MAX }; diff --git a/security/ipe/policy_parser.c b/security/ipe/policy_parser.c index cce15f0eb645..6cab7eef6052 100644 --- a/security/ipe/policy_parser.c +++ b/security/ipe/policy_parser.c @@ -11,6 +11,7 @@ #include "policy.h" #include "policy_parser.h" +#include "digest.h" #define START_COMMENT '#' #define IPE_POLICY_DELIM " \t" @@ -216,6 +217,7 @@ static void free_rule(struct ipe_rule *r) list_for_each_entry_safe(p, t, &r->props, next) { list_del(&p->next); + ipe_digest_free(p->value); kfree(p); } @@ -270,6 +272,11 @@ static const match_table_t property_tokens = { {IPE_PROP_BOOT_VERIFIED_FALSE, "boot_verified=FALSE"}, {IPE_PROP_BOOT_VERIFIED_TRUE, "boot_verified=TRUE"}, #endif /* CONFIG_BLK_DEV_INITRD */ +#ifdef CONFIG_IPE_PROP_DM_VERITY + {IPE_PROP_DMV_ROOTHASH, "dmverity_roothash=%s"}, + {IPE_PROP_DMV_SIG_FALSE, "dmverity_signature=FALSE"}, + {IPE_PROP_DMV_SIG_TRUE, "dmverity_signature=TRUE"}, +#endif /* CONFIG_IPE_PROP_DM_VERITY */ {IPE_PROP_INVALID, NULL} }; @@ -289,6 +296,7 @@ static int parse_property(char *t, struct ipe_rule *r) struct ipe_prop *p = NULL; int rc = 0; int token; + char *dup = NULL; p = kzalloc(sizeof(*p), GFP_KERNEL); if (!p) @@ -297,8 +305,22 @@ static int parse_property(char *t, struct ipe_rule *r) token = match_token(t, property_tokens, args); switch (token) { + case IPE_PROP_DMV_ROOTHASH: + dup = match_strdup(&args[0]); + if (!dup) { + rc = -ENOMEM; + goto err; + } + p->value = ipe_digest_parse(dup); + if (IS_ERR(p->value)) { + rc = PTR_ERR(p->value); + goto err; + } + fallthrough; case IPE_PROP_BOOT_VERIFIED_FALSE: case IPE_PROP_BOOT_VERIFIED_TRUE: + case IPE_PROP_DMV_SIG_FALSE: + case IPE_PROP_DMV_SIG_TRUE: p->type = token; break; default: @@ -309,10 +331,12 @@ static int parse_property(char *t, struct ipe_rule *r) goto err; list_add_tail(&p->next, &r->props); +out: + kfree(dup); return rc; err: kfree(p); - return rc; + goto out; } /**