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ima: extend the measurement list to include the file signature
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This patch defines a new template called 'ima-sig', which includes
the file signature in the template data, in addition to the file's
digest and pathname.

A template is composed of a set of fields.  Associated with each
field is an initialization and display function.  This patch defines
a new template field called 'sig', the initialization function
ima_eventsig_init(), and the display function ima_show_template_sig().

This patch modifies the .field_init() function definition to include
the 'security.ima' extended attribute and length.

Changelog:
- remove unused code (Dmitry Kasatkin)
- avoid calling ima_write_template_field_data() unnecesarily (Roberto Sassu)
- rename DATA_FMT_SIG to DATA_FMT_HEX
- cleanup ima_eventsig_init() based on Roberto's comments

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
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Mimi Zohar committed Nov 1, 2013
1 parent 42a20ba commit bcbc9b0
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Showing 8 changed files with 73 additions and 12 deletions.
3 changes: 3 additions & 0 deletions security/integrity/ima/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -63,13 +63,16 @@ choice
bool "ima"
config IMA_NG_TEMPLATE
bool "ima-ng (default)"
config IMA_SIG_TEMPLATE
bool "ima-sig"
endchoice

config IMA_DEFAULT_TEMPLATE
string
depends on IMA
default "ima" if IMA_TEMPLATE
default "ima-ng" if IMA_NG_TEMPLATE
default "ima-sig" if IMA_SIG_TEMPLATE

choice
prompt "Default integrity hash algorithm"
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10 changes: 7 additions & 3 deletions security/integrity/ima/ima.h
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Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,8 @@ struct ima_template_field {
const char field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN];
int (*field_init) (struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct ima_field_data *field_data);
struct evm_ima_xattr_data *xattr_value,
int xattr_len, struct ima_field_data *field_data);
void (*field_show) (struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data);
};
Expand Down Expand Up @@ -134,12 +135,15 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
struct evm_ima_xattr_data **xattr_value,
int *xattr_len);
void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename);
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
int xattr_len);
void ima_audit_measurement(struct integrity_iint_cache *iint,
const unsigned char *filename);
int ima_alloc_init_template(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct ima_template_entry **entry);
struct evm_ima_xattr_data *xattr_value,
int xattr_len, struct ima_template_entry **entry);
int ima_store_template(struct ima_template_entry *entry, int violation,
struct inode *inode, const unsigned char *filename);
const char *ima_d_path(struct path *path, char **pathbuf);
Expand Down
14 changes: 10 additions & 4 deletions security/integrity/ima/ima_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,8 @@
*/
int ima_alloc_init_template(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct ima_template_entry **entry)
struct evm_ima_xattr_data *xattr_value,
int xattr_len, struct ima_template_entry **entry)
{
struct ima_template_desc *template_desc = ima_template_desc_current();
int i, result = 0;
Expand All @@ -41,6 +42,7 @@ int ima_alloc_init_template(struct integrity_iint_cache *iint,
u32 len;

result = field->field_init(iint, file, filename,
xattr_value, xattr_len,
&((*entry)->template_data[i]));
if (result != 0)
goto out;
Expand Down Expand Up @@ -123,7 +125,8 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
/* can overflow, only indicator */
atomic_long_inc(&ima_htable.violations);

result = ima_alloc_init_template(NULL, file, filename, &entry);
result = ima_alloc_init_template(NULL, file, filename,
NULL, 0, &entry);
if (result < 0) {
result = -ENOMEM;
goto err_out;
Expand Down Expand Up @@ -239,7 +242,9 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
* Must be called with iint->mutex held.
*/
void ima_store_measurement(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename)
struct file *file, const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
int xattr_len)
{
const char *op = "add_template_measure";
const char *audit_cause = "ENOMEM";
Expand All @@ -251,7 +256,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
if (iint->flags & IMA_MEASURED)
return;

result = ima_alloc_init_template(iint, file, filename, &entry);
result = ima_alloc_init_template(iint, file, filename,
xattr_value, xattr_len, &entry);
if (result < 0) {
integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
op, audit_cause, result, 0);
Expand Down
2 changes: 1 addition & 1 deletion security/integrity/ima/ima_init.c
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Original file line number Diff line number Diff line change
Expand Up @@ -69,7 +69,7 @@ static void __init ima_add_boot_aggregate(void)
}

result = ima_alloc_init_template(iint, NULL, boot_aggregate_name,
&entry);
NULL, 0, &entry);
if (result < 0)
return;

Expand Down
3 changes: 2 additions & 1 deletion security/integrity/ima/ima_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -225,7 +225,8 @@ static int process_measurement(struct file *file, const char *filename,
pathname = (const char *)file->f_dentry->d_name.name;

if (action & IMA_MEASURE)
ima_store_measurement(iint, file, pathname);
ima_store_measurement(iint, file, pathname,
xattr_value, xattr_len);
if (action & IMA_APPRAISE_SUBMASK)
rc = ima_appraise_measurement(_func, iint, file, pathname,
xattr_value, xattr_len);
Expand Down
3 changes: 3 additions & 0 deletions security/integrity/ima/ima_template.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
static struct ima_template_desc defined_templates[] = {
{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
{.name = "ima-ng",.fmt = "d-ng|n-ng"},
{.name = "ima-sig",.fmt = "d-ng|n-ng|sig"},
};

static struct ima_template_field supported_fields[] = {
Expand All @@ -31,6 +32,8 @@ static struct ima_template_field supported_fields[] = {
.field_show = ima_show_template_digest_ng},
{.field_id = "n-ng",.field_init = ima_eventname_ng_init,
.field_show = ima_show_template_string},
{.field_id = "sig",.field_init = ima_eventsig_init,
.field_show = ima_show_template_sig},
};

static struct ima_template_desc *ima_template;
Expand Down
38 changes: 36 additions & 2 deletions security/integrity/ima/ima_template_lib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,8 @@ enum data_formats {
DATA_FMT_DIGEST = 0,
DATA_FMT_DIGEST_WITH_ALGO,
DATA_FMT_EVENT_NAME,
DATA_FMT_STRING
DATA_FMT_STRING,
DATA_FMT_HEX
};

static int ima_write_template_field_data(const void *data, const u32 datalen,
Expand Down Expand Up @@ -90,6 +91,9 @@ static void ima_show_template_data_ascii(struct seq_file *m,
buf_ptr += 2;
buflen -= buf_ptr - field_data->data;
case DATA_FMT_DIGEST:
case DATA_FMT_HEX:
if (!buflen)
break;
ima_print_digest(m, buf_ptr, buflen);
break;
case DATA_FMT_STRING:
Expand Down Expand Up @@ -147,6 +151,12 @@ void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
ima_show_template_field_data(m, show, DATA_FMT_STRING, field_data);
}

void ima_show_template_sig(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data)
{
ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data);
}

static int ima_eventdigest_init_common(u8 *digest, u32 digestsize, u8 hash_algo,
struct ima_field_data *field_data,
bool size_limit)
Expand Down Expand Up @@ -190,6 +200,7 @@ static int ima_eventdigest_init_common(u8 *digest, u32 digestsize, u8 hash_algo,
*/
int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data)
{
struct {
Expand Down Expand Up @@ -237,7 +248,8 @@ int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
*/
int ima_eventdigest_ng_init(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct ima_field_data *field_data)
struct evm_ima_xattr_data *xattr_value,
int xattr_len, struct ima_field_data *field_data)
{
u8 *cur_digest = NULL, hash_algo = HASH_ALGO__LAST;
u32 cur_digestsize = 0;
Expand Down Expand Up @@ -295,6 +307,7 @@ static int ima_eventname_init_common(struct integrity_iint_cache *iint,
*/
int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data)
{
return ima_eventname_init_common(iint, file, filename,
Expand All @@ -306,8 +319,29 @@ int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
*/
int ima_eventname_ng_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data)
{
return ima_eventname_init_common(iint, file, filename,
field_data, false);
}

/*
* ima_eventsig_init - include the file signature as part of the template data
*/
int ima_eventsig_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data)
{
enum data_formats fmt = DATA_FMT_HEX;
int rc = 0;

if ((!xattr_value) || (xattr_value->type != EVM_IMA_XATTR_DIGSIG))
goto out;

rc = ima_write_template_field_data(xattr_value, xattr_len, fmt,
field_data);
out:
return rc;
}
12 changes: 11 additions & 1 deletion security/integrity/ima/ima_template_lib.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,16 +24,26 @@ void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data);
void ima_show_template_string(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data);
void ima_show_template_sig(struct seq_file *m, enum ima_show_type show,
struct ima_field_data *field_data);
int ima_eventdigest_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data);
int ima_eventname_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data);
int ima_eventdigest_ng_init(struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct ima_field_data *field_data);
struct evm_ima_xattr_data *xattr_value,
int xattr_len, struct ima_field_data *field_data);
int ima_eventname_ng_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data);
int ima_eventsig_init(struct integrity_iint_cache *iint, struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value, int xattr_len,
struct ima_field_data *field_data);
#endif /* __LINUX_IMA_TEMPLATE_LIB_H */

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