| Message ID | ZfuzWku+ip4fsZrb@neat (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | [v3,next] integrity: Avoid -Wflex-array-member-not-at-end warnings | expand |
On Wed, 2024-03-20 at 22:11 -0600, Gustavo A. R. Silva wrote: > -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; > > 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'. > 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:45:32: warning: structure containing a flexible > array member is not at the end of another structure [-Wflex-array-member-not- > at-end] > security/integrity/evm/evm.h:45:32: warning: structure containing a flexible > array member is not at the end of another structure [-Wflex-array-member-not- > at-end] > security/integrity/evm/evm.h:45:32: warning: structure containing a flexible > array member is not at the end of another structure [-Wflex-array-member-not- > at-end] I assume these messages are gone. thanks, Mimi > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > --- > Changes in v3: > - struct ima_digest_data is a packed structure. So, to keep things > consistent, use the attribute __packed on the tagged struct > ima_digest_data_hdr. For this, we use __struct_group() instead of > struct_group_tagged(). Update the changelog text, accordingly. > > Changes in v2: > - Include changes for `struct evm_digest` (Mimi Zohar) >
On 3/21/24 07:58, Mimi Zohar wrote: > On Wed, 2024-03-20 at 22:11 -0600, Gustavo A. R. Silva wrote: >> -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; >> >> 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'. Yes. :) > > >> 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:45:32: warning: structure containing a flexible >> array member is not at the end of another structure [-Wflex-array-member-not- >> at-end] >> security/integrity/evm/evm.h:45:32: warning: structure containing a flexible >> array member is not at the end of another structure [-Wflex-array-member-not- >> at-end] >> security/integrity/evm/evm.h:45:32: warning: structure containing a flexible >> array member is not at the end of another structure [-Wflex-array-member-not- >> at-end] > > I assume these messages are gone. Yes. :) Thanks -- Gustavo
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index eb1a2c343bd7..72e3341ae6f7 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -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; diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index b37d043d5748..c7c8d1bffb17 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -247,6 +247,8 @@ int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file, struct inode *real_inode = d_real_inode(file_dentry(file)); const char *filename = file->f_path.dentry->d_name.name; struct ima_max_digest_data hash; + struct ima_digest_data *hash_hdr = container_of(&hash.hdr, + struct ima_digest_data, hdr); struct kstat stat; int result = 0; int length; @@ -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) diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 3497741caea9..656c709b974f 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -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; diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 393f5c7912d5..4e208239a40e 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -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; diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index c84e8c55333d..0d3a7c864fd4 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -941,6 +941,8 @@ 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; @@ -979,7 +981,7 @@ 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]; @@ -990,7 +992,7 @@ 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); diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c index 6cd0add524cd..74198d7619da 100644 --- a/security/integrity/ima/ima_template_lib.c +++ b/security/integrity/ima/ima_template_lib.c @@ -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, diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index 50d6f798e613..3847a23509f1 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -44,6 +44,7 @@ struct evm_xattr { #define IMA_MAX_DIGEST_SIZE HASH_MAX_DIGESTSIZE struct ima_digest_data { + __struct_group(ima_digest_data_hdr, hdr, __packed, u8 algo; u8 length; union { @@ -57,6 +58,7 @@ struct ima_digest_data { } ng; u8 data[2]; } xattr; + ); u8 digest[]; } __packed; @@ -65,7 +67,7 @@ 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;
-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; 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; 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:45:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] security/integrity/evm/evm.h:45:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] security/integrity/evm/evm.h:45:32: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- Changes in v3: - struct ima_digest_data is a packed structure. So, to keep things consistent, use the attribute __packed on the tagged struct ima_digest_data_hdr. For this, we use __struct_group() instead of struct_group_tagged(). Update the changelog text, accordingly. Changes in v2: - Include changes for `struct evm_digest` (Mimi Zohar) security/integrity/evm/evm.h | 2 +- security/integrity/ima/ima_api.c | 6 ++++-- security/integrity/ima/ima_appraise.c | 4 +++- security/integrity/ima/ima_init.c | 6 ++++-- security/integrity/ima/ima_main.c | 6 ++++-- security/integrity/ima/ima_template_lib.c | 10 ++++++---- security/integrity/integrity.h | 4 +++- 7 files changed, 25 insertions(+), 13 deletions(-)