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integrity: Avoid -Wflex-array-member-not-at-end warnings

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-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
ready to enable it globally.

There is currently an object (`hdr)` in `struct ima_max_digest_data`
that contains a flexible structure (`struct ima_digest_data`):

 struct ima_max_digest_data {
        struct ima_digest_data hdr;
        u8 digest[HASH_MAX_DIGESTSIZE];
 } __packed;

So, in order to avoid ending up with a flexible-array member in the
middle of a struct, we use the `__struct_group()` helper to separate
the flexible array from the rest of the members in the flexible
structure:

struct ima_digest_data {
        __struct_group(ima_digest_data_hdr, hdr, __packed,

        ... the rest of the members

        );
        u8 digest[];
} __packed;

And similarly for `struct evm_ima_xattr_data`.

With the change described above, we can now declare an object of the
type of the tagged `struct ima_digest_data_hdr`, without embedding the
flexible array in the middle of another struct:

 struct ima_max_digest_data {
        struct ima_digest_data_hdr hdr;
        u8 digest[HASH_MAX_DIGESTSIZE];
 } __packed;

And similarly for `struct evm_digest` and `struct evm_xattr`.

We also use `container_of()` whenever we need to retrieve a pointer to
the flexible structure.

So, with these changes, fix the following warnings:

security/integrity/evm/evm.h:64:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/evm/../integrity.h:40:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/evm/../integrity.h:68:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/ima/../integrity.h:40:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/ima/../integrity.h:68:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/integrity.h:40:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/integrity.h:68:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/platform_certs/../integrity.h:40:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
security/integrity/platform_certs/../integrity.h:68:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Link: https://github.com/KSPP/linux/issues/202
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Gustavo A. R. Silva 2024-04-04 09:00:48 -06:00 committed by Mimi Zohar
parent cc293c8466
commit 38aa3f5ac6
7 changed files with 31 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
security/integrity/evm/evm.h
View File

@ -61,7 +61,7 @@ extern int evm_hmac_attrs;
extern struct list_head evm_config_xattrnames;
struct evm_digest {
struct ima_digest_data hdr;
struct ima_digest_data_hdr hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} __packed;

6
security/integrity/ima/ima_api.c
View File

@ -246,6 +246,8 @@ int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file,
struct inode *inode = file_inode(file);
struct inode *real_inode = d_real_inode(file_dentry(file));
struct ima_max_digest_data hash;
struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
struct ima_digest_data, hdr);
struct name_snapshot filename;
struct kstat stat;
int result = 0;
@ -286,9 +288,9 @@ int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file,
result = -ENODATA;
}
} else if (buf) {
result = ima_calc_buffer_hash(buf, size, &hash.hdr);
result = ima_calc_buffer_hash(buf, size, hash_hdr);
} else {
result = ima_calc_file_hash(file, &hash.hdr);
result = ima_calc_file_hash(file, hash_hdr);
}
if (result && result != -EBADF && result != -EINVAL)

4
security/integrity/ima/ima_appraise.c
View File

@ -378,7 +378,9 @@ static int xattr_verify(enum ima_hooks func, struct ima_iint_cache *iint,
}
rc = calc_file_id_hash(IMA_VERITY_DIGSIG, iint->ima_hash->algo,
iint->ima_hash->digest, &hash.hdr);
iint->ima_hash->digest,
container_of(&hash.hdr,
struct ima_digest_data, hdr));
if (rc) {
*cause = "sigv3-hashing-error";
*status = INTEGRITY_FAIL;

6
security/integrity/ima/ima_init.c
View File

@ -48,12 +48,14 @@ static int __init ima_add_boot_aggregate(void)
struct ima_event_data event_data = { .iint = iint,
.filename = boot_aggregate_name };
struct ima_max_digest_data hash;
struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
struct ima_digest_data, hdr);
int result = -ENOMEM;
int violation = 0;
memset(iint, 0, sizeof(*iint));
memset(&hash, 0, sizeof(hash));
iint->ima_hash = &hash.hdr;
iint->ima_hash = hash_hdr;
iint->ima_hash->algo = ima_hash_algo;
iint->ima_hash->length = hash_digest_size[ima_hash_algo];
@ -70,7 +72,7 @@ static int __init ima_add_boot_aggregate(void)
* is not found.
*/
if (ima_tpm_chip) {
result = ima_calc_boot_aggregate(&hash.hdr);
result = ima_calc_boot_aggregate(hash_hdr);
if (result < 0) {
audit_cause = "hashing_error";
goto err_out;

6
security/integrity/ima/ima_main.c
View File

@ -948,6 +948,8 @@ int process_buffer_measurement(struct mnt_idmap *idmap,
.buf_len = size};
struct ima_template_desc *template;
struct ima_max_digest_data hash;
struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
struct ima_digest_data, hdr);
char digest_hash[IMA_MAX_DIGEST_SIZE];
int digest_hash_len = hash_digest_size[ima_hash_algo];
int violation = 0;
@ -986,7 +988,7 @@ int process_buffer_measurement(struct mnt_idmap *idmap,
if (!pcr)
pcr = CONFIG_IMA_MEASURE_PCR_IDX;
iint.ima_hash = &hash.hdr;
iint.ima_hash = hash_hdr;
iint.ima_hash->algo = ima_hash_algo;
iint.ima_hash->length = hash_digest_size[ima_hash_algo];
@ -997,7 +999,7 @@ int process_buffer_measurement(struct mnt_idmap *idmap,
}
if (buf_hash) {
memcpy(digest_hash, hash.hdr.digest, digest_hash_len);
memcpy(digest_hash, hash_hdr->digest, digest_hash_len);
ret = ima_calc_buffer_hash(digest_hash, digest_hash_len,
iint.ima_hash);

10
security/integrity/ima/ima_template_lib.c
View File

@ -339,6 +339,8 @@ int ima_eventdigest_init(struct ima_event_data *event_data,
struct ima_field_data *field_data)
{
struct ima_max_digest_data hash;
struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
struct ima_digest_data, hdr);
u8 *cur_digest = NULL;
u32 cur_digestsize = 0;
struct inode *inode;
@ -358,7 +360,7 @@ int ima_eventdigest_init(struct ima_event_data *event_data,
if ((const char *)event_data->filename == boot_aggregate_name) {
if (ima_tpm_chip) {
hash.hdr.algo = HASH_ALGO_SHA1;
result = ima_calc_boot_aggregate(&hash.hdr);
result = ima_calc_boot_aggregate(hash_hdr);
/* algo can change depending on available PCR banks */
if (!result && hash.hdr.algo != HASH_ALGO_SHA1)
@ -368,7 +370,7 @@ int ima_eventdigest_init(struct ima_event_data *event_data,
memset(&hash, 0, sizeof(hash));
}
cur_digest = hash.hdr.digest;
cur_digest = hash_hdr->digest;
cur_digestsize = hash_digest_size[HASH_ALGO_SHA1];
goto out;
}
@ -379,14 +381,14 @@ int ima_eventdigest_init(struct ima_event_data *event_data,
inode = file_inode(event_data->file);
hash.hdr.algo = ima_template_hash_algo_allowed(ima_hash_algo) ?
ima_hash_algo : HASH_ALGO_SHA1;
result = ima_calc_file_hash(event_data->file, &hash.hdr);
result = ima_calc_file_hash(event_data->file, hash_hdr);
if (result) {
integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
event_data->filename, "collect_data",
"failed", result, 0);
return result;
}
cur_digest = hash.hdr.digest;
cur_digest = hash_hdr->digest;
cur_digestsize = hash.hdr.length;
out:
return ima_eventdigest_init_common(cur_digest, cur_digestsize,

12
security/integrity/integrity.h
View File

@ -31,19 +31,24 @@ enum evm_ima_xattr_type {
};
struct evm_ima_xattr_data {
u8 type;
/* New members must be added within the __struct_group() macro below. */
__struct_group(evm_ima_xattr_data_hdr, hdr, __packed,
u8 type;
);
u8 data[];
} __packed;
/* Only used in the EVM HMAC code. */
struct evm_xattr {
struct evm_ima_xattr_data data;
struct evm_ima_xattr_data_hdr data;
u8 digest[SHA1_DIGEST_SIZE];
} __packed;
#define IMA_MAX_DIGEST_SIZE HASH_MAX_DIGESTSIZE
struct ima_digest_data {
/* New members must be added within the __struct_group() macro below. */
__struct_group(ima_digest_data_hdr, hdr, __packed,
u8 algo;
u8 length;
union {
@ -57,6 +62,7 @@ struct ima_digest_data {
} ng;
u8 data[2];
} xattr;
);
u8 digest[];
} __packed;
@ -65,7 +71,7 @@ struct ima_digest_data {
* with the maximum hash size, define ima_max_digest_data struct.
*/
struct ima_max_digest_data {
struct ima_digest_data hdr;
struct ima_digest_data_hdr hdr;
u8 digest[HASH_MAX_DIGESTSIZE];
} __packed;