> From: Lakshmi Ramasubramanian [mailto:nramas@xxxxxxxxxxxxxxxxxxx] > Sent: Thursday, July 1, 2021 6:16 PM > On 7/1/2021 5:55 AM, Roberto Sassu wrote: > > ima_measure_critical_data() and process_buffer_measurement() currently > > don't return a result. A caller wouldn't be able to know whether those > > functions were executed successfully. > > > > This patch modifies the return type from void to int, and returns 0 if the > > buffer has been successfully measured, a negative value otherwise. > > > > Also, this patch does not modify the behavior of existing callers by > > processing the returned value. Instead, the value is stored in a variable > > marked as __maybe_unused. > > > > Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx> > > --- > > include/linux/ima.h | 15 +++--- > > security/integrity/ima/ima.h | 10 ++-- > > security/integrity/ima/ima_appraise.c | 4 +- > > security/integrity/ima/ima_asymmetric_keys.c | 4 +- > > security/integrity/ima/ima_init.c | 6 ++- > > security/integrity/ima/ima_main.c | 48 ++++++++++++-------- > > security/integrity/ima/ima_queue_keys.c | 15 +++--- > > security/selinux/ima.c | 10 ++-- > > 8 files changed, 66 insertions(+), 46 deletions(-) > > > > diff --git a/include/linux/ima.h b/include/linux/ima.h > > index 81e830d01ced..60492263aa64 100644 > > --- a/include/linux/ima.h > > +++ b/include/linux/ima.h > > @@ -35,10 +35,10 @@ extern void ima_post_path_mknod(struct > user_namespace *mnt_userns, > > extern int ima_file_hash(struct file *file, char *buf, size_t buf_size); > > extern int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size); > > extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size); > > -extern void ima_measure_critical_data(const char *event_label, > > - const char *event_name, > > - const void *buf, size_t buf_len, > > - bool hash); > > +extern int ima_measure_critical_data(const char *event_label, > > + const char *event_name, > > + const void *buf, size_t buf_len, > > + bool hash); > > > > #ifdef CONFIG_IMA_APPRAISE_BOOTPARAM > > extern void ima_appraise_parse_cmdline(void); > > @@ -144,10 +144,13 @@ static inline int ima_inode_hash(struct inode > *inode, char *buf, size_t buf_size > > > > static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) > {} > > > > -static inline void ima_measure_critical_data(const char *event_label, > > +static inline int ima_measure_critical_data(const char *event_label, > > const char *event_name, > > const void *buf, size_t buf_len, > > - bool hash) {} > > + bool hash) > > +{ > > + return -ENOENT; > > +} > > > > #endif /* CONFIG_IMA */ > > > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > > index f0e448ed1f9f..03db221324c3 100644 > > --- a/security/integrity/ima/ima.h > > +++ b/security/integrity/ima/ima.h > > @@ -264,11 +264,11 @@ void ima_store_measurement(struct > integrity_iint_cache *iint, struct file *file, > > struct evm_ima_xattr_data *xattr_value, > > int xattr_len, const struct modsig *modsig, int pcr, > > struct ima_template_desc *template_desc); > > -void process_buffer_measurement(struct user_namespace *mnt_userns, > > - struct inode *inode, const void *buf, int size, > > - const char *eventname, enum ima_hooks > func, > > - int pcr, const char *func_data, > > - bool buf_hash); > > +int process_buffer_measurement(struct user_namespace *mnt_userns, > > + struct inode *inode, const void *buf, int size, > > + const char *eventname, enum ima_hooks func, > > + int pcr, const char *func_data, > > + bool buf_hash); > > void ima_audit_measurement(struct integrity_iint_cache *iint, > > const unsigned char *filename); > > int ima_alloc_init_template(struct ima_event_data *event_data, > > diff --git a/security/integrity/ima/ima_appraise.c > b/security/integrity/ima/ima_appraise.c > > index ef9dcfce45d4..275a2377743f 100644 > > --- a/security/integrity/ima/ima_appraise.c > > +++ b/security/integrity/ima/ima_appraise.c > > @@ -345,6 +345,7 @@ int ima_check_blacklist(struct integrity_iint_cache > *iint, > > enum hash_algo hash_algo; > > const u8 *digest = NULL; > > u32 digestsize = 0; > > + int process_rc __maybe_unused; > > int rc = 0; > > > > if (!(iint->flags & IMA_CHECK_BLACKLIST)) > > @@ -355,7 +356,8 @@ int ima_check_blacklist(struct integrity_iint_cache > *iint, > > > > rc = is_binary_blacklisted(digest, digestsize); > > if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) > > - process_buffer_measurement(&init_user_ns, NULL, > digest, digestsize, > > + process_rc = > process_buffer_measurement(&init_user_ns, > I think there is no need to make this change now. If and when > ima_check_blacklist() needs to look at the return value of p_b_m(), this > change can be made. Hi Lakshmi ok. I was worried about possible warnings. If it is not an issue, I will remove the assignment. Thanks Roberto HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Li Jian, Shi Yanli > > + NULL, digest, digestsize, > > "blacklisted-hash", NONE, > > pcr, NULL, false); > > } > > diff --git a/security/integrity/ima/ima_asymmetric_keys.c > b/security/integrity/ima/ima_asymmetric_keys.c > > index c985418698a4..910367cdd920 100644 > > --- a/security/integrity/ima/ima_asymmetric_keys.c > > +++ b/security/integrity/ima/ima_asymmetric_keys.c > > @@ -31,6 +31,7 @@ void ima_post_key_create_or_update(struct key > *keyring, struct key *key, > > unsigned long flags, bool create) > > { > > bool queued = false; > > + int ret __maybe_unused; > > > > /* Only asymmetric keys are handled by this hook. */ > > if (key->type != &key_type_asymmetric) > > @@ -60,7 +61,8 @@ void ima_post_key_create_or_update(struct key > *keyring, struct key *key, > > * if the IMA policy is configured to measure a key linked > > * to the given keyring. > > */ > > - process_buffer_measurement(&init_user_ns, NULL, payload, > payload_len, > > + ret = process_buffer_measurement(&init_user_ns, NULL, > > + payload, payload_len, > Same comment as in ima_check_blacklist() - this change be made when > needed. > > > keyring->description, KEY_CHECK, 0, > > keyring->description, false); > > } > > diff --git a/security/integrity/ima/ima_init.c > b/security/integrity/ima/ima_init.c > > index 5076a7d9d23e..6790eea88db8 100644 > > --- a/security/integrity/ima/ima_init.c > > +++ b/security/integrity/ima/ima_init.c > > @@ -118,6 +118,7 @@ void __init ima_load_x509(void) > > > > int __init ima_init(void) > > { > > + int measure_rc __maybe_unused; > > int rc; > > > > ima_tpm_chip = tpm_default_chip(); > > @@ -153,8 +154,9 @@ int __init ima_init(void) > > > > ima_init_key_queue(); > > > > - ima_measure_critical_data("kernel_info", "kernel_version", > > - UTS_RELEASE, strlen(UTS_RELEASE), false); > > + measure_rc = ima_measure_critical_data("kernel_info", > "kernel_version", > > + UTS_RELEASE, > strlen(UTS_RELEASE), > > + false); > Same comment as in ima_check_blacklist() - this change be made when > needed. > > > > > return rc; > > } > > diff --git a/security/integrity/ima/ima_main.c > b/security/integrity/ima/ima_main.c > > index 8ef1fa357e0c..3386e7436440 100644 > > --- a/security/integrity/ima/ima_main.c > > +++ b/security/integrity/ima/ima_main.c > > @@ -827,7 +827,7 @@ int ima_post_load_data(char *buf, loff_t size, > > return 0; > > } > > > > -/* > > +/** > > * process_buffer_measurement - Measure the buffer or the buffer data > hash > > * @mnt_userns: user namespace of the mount the inode was found > from > > * @inode: inode associated with the object being measured (NULL for > KEY_CHECK) > > @@ -840,12 +840,15 @@ int ima_post_load_data(char *buf, loff_t size, > > * @buf_hash: measure buffer data hash > > * > > * Based on policy, either the buffer data or buffer data hash is measured > > + * > > + * Return: 0 if the buffer has been successfully measured, a negative value > > + * otherwise. > > */ > > -void process_buffer_measurement(struct user_namespace *mnt_userns, > > - struct inode *inode, const void *buf, int size, > > - const char *eventname, enum ima_hooks > func, > > - int pcr, const char *func_data, > > - bool buf_hash) > > +int process_buffer_measurement(struct user_namespace *mnt_userns, > > + struct inode *inode, const void *buf, int size, > > + const char *eventname, enum ima_hooks func, > > + int pcr, const char *func_data, > > + bool buf_hash) > > { > > int ret = 0; > > const char *audit_cause = "ENOMEM"; > > @@ -867,7 +870,7 @@ void process_buffer_measurement(struct > user_namespace *mnt_userns, > > u32 secid; > > > > if (!ima_policy_flag) > > - return; > > + return -ENOENT; > > > > template = ima_template_desc_buf(); > > if (!template) { > > @@ -889,7 +892,7 @@ void process_buffer_measurement(struct > user_namespace *mnt_userns, > > secid, 0, func, &pcr, &template, > > func_data); > > if (!(action & IMA_MEASURE)) > > - return; > > + return -ENOENT; > > } > > > > if (!pcr) > > @@ -937,7 +940,7 @@ void process_buffer_measurement(struct > user_namespace *mnt_userns, > > func_measure_str(func), > > audit_cause, ret, 0, ret); > > > > - return; > > + return ret; > > } > > > > /** > > @@ -951,6 +954,7 @@ void process_buffer_measurement(struct > user_namespace *mnt_userns, > > void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) > > { > > struct fd f; > > + int ret __maybe_unused; > > > > if (!buf || !size) > > return; > > @@ -959,9 +963,10 @@ void ima_kexec_cmdline(int kernel_fd, const void > *buf, int size) > > if (!f.file) > > return; > > > > - process_buffer_measurement(file_mnt_user_ns(f.file), > file_inode(f.file), > > - buf, size, "kexec-cmdline", KEXEC_CMDLINE, > 0, > > - NULL, false); > > + ret = process_buffer_measurement(file_mnt_user_ns(f.file), > > + file_inode(f.file), buf, size, > > + "kexec-cmdline", KEXEC_CMDLINE, 0, > > + NULL, false); > Since the return value of p_b_m() is not used here, this change can be > made when needed. > > > fdput(f); > > } > > > > @@ -977,18 +982,21 @@ void ima_kexec_cmdline(int kernel_fd, const void > *buf, int size) > > * and extend the pcr. Examples of critical data could be various data > > * structures, policies, and states stored in kernel memory that can > > * impact the integrity of the system. > > + * > > + * Return: 0 if the buffer has been successfully measured, a negative value > > + * otherwise. > > */ > > -void ima_measure_critical_data(const char *event_label, > > - const char *event_name, > > - const void *buf, size_t buf_len, > > - bool hash) > > +int ima_measure_critical_data(const char *event_label, > > + const char *event_name, > > + const void *buf, size_t buf_len, > > + bool hash) > > { > > if (!event_name || !event_label || !buf || !buf_len) > > - return; > > + return -ENOPARAM; > > > > - process_buffer_measurement(&init_user_ns, NULL, buf, buf_len, > event_name, > > - CRITICAL_DATA, 0, event_label, > > - hash); > > + return process_buffer_measurement(&init_user_ns, NULL, buf, > buf_len, > > + event_name, CRITICAL_DATA, 0, > > + event_label, hash); > > } > > > > static int __init init_ima(void) > > diff --git a/security/integrity/ima/ima_queue_keys.c > b/security/integrity/ima/ima_queue_keys.c > > index 979ef6c71f3d..e3047ce64f39 100644 > > --- a/security/integrity/ima/ima_queue_keys.c > > +++ b/security/integrity/ima/ima_queue_keys.c > > @@ -134,6 +134,7 @@ void ima_process_queued_keys(void) > > { > > struct ima_key_entry *entry, *tmp; > > bool process = false; > > + int ret __maybe_unused; > > > > if (ima_process_keys) > > return; > > @@ -159,13 +160,13 @@ void ima_process_queued_keys(void) > > > > list_for_each_entry_safe(entry, tmp, &ima_keys, list) { > > if (!timer_expired) > > - process_buffer_measurement(&init_user_ns, NULL, > > - entry->payload, > > - entry->payload_len, > > - entry->keyring_name, > > - KEY_CHECK, 0, > > - entry->keyring_name, > > - false); > > + ret = process_buffer_measurement(&init_user_ns, > NULL, > > + entry->payload, > > + entry->payload_len, > > + entry- > >keyring_name, > > + KEY_CHECK, 0, > > + entry- > >keyring_name, > > + false); > Same comment as above. > > > list_del(&entry->list); > > ima_free_key_entry(entry); > > } > > diff --git a/security/selinux/ima.c b/security/selinux/ima.c > > index 34d421861bfc..4db9fa211638 100644 > > --- a/security/selinux/ima.c > > +++ b/security/selinux/ima.c > > @@ -75,6 +75,7 @@ void selinux_ima_measure_state_locked(struct > selinux_state *state) > > char *state_str = NULL; > > void *policy = NULL; > > size_t policy_len; > > + int measure_rc __maybe_unused; > > int rc = 0; > > > > WARN_ON(!mutex_is_locked(&state->policy_mutex)); > > @@ -85,8 +86,9 @@ void selinux_ima_measure_state_locked(struct > selinux_state *state) > > return; > > } > > > > - ima_measure_critical_data("selinux", "selinux-state", > > - state_str, strlen(state_str), false); > > + measure_rc = ima_measure_critical_data("selinux", "selinux-state", > > + state_str, strlen(state_str), > > + false); > Since the return value of ima_measure_critical_data() is not used here, > this change can be made when needed. > > > > > kfree(state_str); > > > > @@ -102,8 +104,8 @@ void selinux_ima_measure_state_locked(struct > selinux_state *state) > > return; > > } > > > > - ima_measure_critical_data("selinux", "selinux-policy-hash", > > - policy, policy_len, true); > > + measure_rc = ima_measure_critical_data("selinux", "selinux-policy- > hash", > > + policy, policy_len, true); > Same comment as above. > > -lakshmi > > > > > vfree(policy); > > } > >
