| Message ID | 20191113184658.2862-2-nramas@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KEYS: Measure keys when they are created or updated | expand |
On Wed, 2019-11-13 at 10:46 -0800, Lakshmi Ramasubramanian wrote: > Measure keys loaded onto any keyring. > > This patch defines a new IMA policy func namely KEY_CHECK to > measure keys. Updated ima_match_rules() to check for KEY_CHECK > and ima_parse_rule() to handle KEY_CHECK. > > Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> > --- > Documentation/ABI/testing/ima_policy | 6 +++++- > security/integrity/ima/ima.h | 1 + > security/integrity/ima/ima_main.c | 7 +++++++ > security/integrity/ima/ima_policy.c | 4 +++- > 4 files changed, 16 insertions(+), 2 deletions(-) > > diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy > index 29aaedf33246..066d32797500 100644 > --- a/Documentation/ABI/testing/ima_policy > +++ b/Documentation/ABI/testing/ima_policy > @@ -29,7 +29,7 @@ Description: > base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] > [FIRMWARE_CHECK] > [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] > - [KEXEC_CMDLINE] > + [KEXEC_CMDLINE] [KEY_CHECK] > mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] > [[^]MAY_EXEC] > fsmagic:= hex value > @@ -113,3 +113,7 @@ Description: > Example of appraise rule allowing modsig appended signatures: > > appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig > + > + Example of measure rule using KEY_CHECK to measure all keys: > + > + measure func=KEY_CHECK > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index df4ca482fb53..fe6c698617bd 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -193,6 +193,7 @@ static inline unsigned long ima_hash_key(u8 *digest) > hook(KEXEC_INITRAMFS_CHECK) \ > hook(POLICY_CHECK) \ > hook(KEXEC_CMDLINE) \ > + hook(KEY_CHECK) \ > hook(MAX_CHECK) > #define __ima_hook_enumify(ENUM) ENUM, > > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index d7e987baf127..12684e8d7124 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -655,6 +655,13 @@ void process_buffer_measurement(const void *buf, int size, > int action = 0; > u32 secid; > > + /* > + * If IMA is not yet initialized or IMA policy is empty > + * then there is no need to measure. > + */ > + if (!ima_policy_flag) > + return; > + This addition has nothing to do with defining a new IMA hook and should be a separate patch. This can be posted independently of this patch set. Mimi > /* > * Both LSM hooks and auxilary based buffer measurements are > * based on policy. To avoid code duplication, differentiate > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c > index f19a895ad7cd..1525a28fd705 100644 > --- a/security/integrity/ima/ima_policy.c > +++ b/security/integrity/ima/ima_policy.c > @@ -373,7 +373,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, > { > int i; > > - if (func == KEXEC_CMDLINE) { > + if ((func == KEXEC_CMDLINE) || (func == KEY_CHECK)) { > if ((rule->flags & IMA_FUNC) && (rule->func == func)) > return true; > return false; > @@ -997,6 +997,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) > entry->func = POLICY_CHECK; > else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0) > entry->func = KEXEC_CMDLINE; > + else if (strcmp(args[0].from, "KEY_CHECK") == 0) > + entry->func = KEY_CHECK; > else > result = -EINVAL; > if (!result)
On 11/13/2019 12:14 PM, Mimi Zohar wrote: >> @@ -655,6 +655,13 @@ void process_buffer_measurement(const void *buf, int size, >> int action = 0; >> u32 secid; >> >> + /* >> + * If IMA is not yet initialized or IMA policy is empty >> + * then there is no need to measure. >> + */ >> + if (!ima_policy_flag) >> + return; >> + > > This addition has nothing to do with defining a new IMA hook and > should be a separate patch. This can be posted independently of this > patch set. > > Mimi I'll move this change to a different patch, but it has to be either part of this patch set or the above change alone needs to be taken before this patch set for the following reason: The IMA hook gets called early in the boot process (for example, when builtin_trusted_keys are added). If the above check is not there, ima_get_action() is called and causes kernel panic (since IMA is not yet initialized). thanks, -lakshmi
On Wed, 2019-11-13 at 12:21 -0800, Lakshmi Ramasubramanian wrote: > On 11/13/2019 12:14 PM, Mimi Zohar wrote: > > >> @@ -655,6 +655,13 @@ void process_buffer_measurement(const void *buf, int size, > >> int action = 0; > >> u32 secid; > >> > >> + /* > >> + * If IMA is not yet initialized or IMA policy is empty > >> + * then there is no need to measure. > >> + */ > >> + if (!ima_policy_flag) > >> + return; > >> + > > > > This addition has nothing to do with defining a new IMA hook and > > should be a separate patch. This can be posted independently of this > > patch set. > > > > Mimi > > I'll move this change to a different patch, > but it has to be either part of this patch set or the above change alone > needs to be taken before this patch set for the following reason: > > The IMA hook gets called early in the boot process (for example, when > builtin_trusted_keys are added). If the above check is not there, > ima_get_action() is called and causes kernel panic (since IMA is not yet > initialized). It will be upstreamed prior to this patch set. Mimi
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 29aaedf33246..066d32797500 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -29,7 +29,7 @@ Description: base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] - [KEXEC_CMDLINE] + [KEXEC_CMDLINE] [KEY_CHECK] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value @@ -113,3 +113,7 @@ Description: Example of appraise rule allowing modsig appended signatures: appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig + + Example of measure rule using KEY_CHECK to measure all keys: + + measure func=KEY_CHECK diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index df4ca482fb53..fe6c698617bd 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -193,6 +193,7 @@ static inline unsigned long ima_hash_key(u8 *digest) hook(KEXEC_INITRAMFS_CHECK) \ hook(POLICY_CHECK) \ hook(KEXEC_CMDLINE) \ + hook(KEY_CHECK) \ hook(MAX_CHECK) #define __ima_hook_enumify(ENUM) ENUM, diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index d7e987baf127..12684e8d7124 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -655,6 +655,13 @@ void process_buffer_measurement(const void *buf, int size, int action = 0; u32 secid; + /* + * If IMA is not yet initialized or IMA policy is empty + * then there is no need to measure. + */ + if (!ima_policy_flag) + return; + /* * Both LSM hooks and auxilary based buffer measurements are * based on policy. To avoid code duplication, differentiate diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index f19a895ad7cd..1525a28fd705 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -373,7 +373,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, { int i; - if (func == KEXEC_CMDLINE) { + if ((func == KEXEC_CMDLINE) || (func == KEY_CHECK)) { if ((rule->flags & IMA_FUNC) && (rule->func == func)) return true; return false; @@ -997,6 +997,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) entry->func = POLICY_CHECK; else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0) entry->func = KEXEC_CMDLINE; + else if (strcmp(args[0].from, "KEY_CHECK") == 0) + entry->func = KEY_CHECK; else result = -EINVAL; if (!result)
Measure keys loaded onto any keyring. This patch defines a new IMA policy func namely KEY_CHECK to measure keys. Updated ima_match_rules() to check for KEY_CHECK and ima_parse_rule() to handle KEY_CHECK. Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> --- Documentation/ABI/testing/ima_policy | 6 +++++- security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_main.c | 7 +++++++ security/integrity/ima/ima_policy.c | 4 +++- 4 files changed, 16 insertions(+), 2 deletions(-)