Messages in this thread | | | Subject | Re: [PATCH v3 2/3] ima: Return int in the functions to measure a buffer | From | Lakshmi Ramasubramanian <> | Date | Tue, 6 Jul 2021 12:21:04 -0700 |
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On 7/5/2021 2:09 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. For those, the return value is ignored. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > --- > include/linux/ima.h | 15 +++++++----- > security/integrity/ima/ima.h | 10 ++++---- > security/integrity/ima/ima_main.c | 40 ++++++++++++++++++------------- > 3 files changed, 37 insertions(+), 28 deletions(-)
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
-lakshmi
> > 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_main.c b/security/integrity/ima/ima_main.c > index 8ef1fa357e0c..b512c06d8ee1 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; > } > > /** > @@ -977,18 +980,21 @@ 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) >
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