From aca562e43d09dfd2373b0d9415e5170ddd616a38 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] integrity: Avoid -Wflex-array-member-not-at-end warnings BugLink: https://bugs.launchpad.net/bugs/2101915 -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 Signed-off-by: Mimi Zohar (cherry picked from commit 38aa3f5ac6d2de6b471ecb6e1cd878957ae7e8de) [koichiroden: prerequisite for the subsequent commit] Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- 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 | 12 +++++++++--- 7 files changed, 31 insertions(+), 15 deletions(-) diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h index 53bd7fec93fa..6b6d41a0e9f8 100644 --- a/security/integrity/evm/evm.h +++ b/security/integrity/evm/evm.h @@ -42,7 +42,7 @@ 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 af894d1e4d85..636175e5dcff 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -245,6 +245,8 @@ int ima_collect_measurement(struct integrity_iint_cache *iint, 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; @@ -285,9 +287,9 @@ int ima_collect_measurement(struct integrity_iint_cache *iint, 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 41cf92d15972..a68db852b1f6 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -380,7 +380,9 @@ static int xattr_verify(enum ima_hooks func, struct integrity_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 63979aefc95f..11d1f8b8fe99 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 c69eb9665cc1..dea4b49c1e46 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 e474f6a2cc85..0e627eac9c33 100644 --- a/security/integrity/ima/ima_template_lib.c +++ b/security/integrity/ima/ima_template_lib.c @@ -345,6 +345,8 @@ 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; @@ -364,7 +366,7 @@ 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) @@ -374,7 +376,7 @@ 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; } @@ -385,14 +387,14 @@ 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 9561db7cf6b4..e8a34e8dee19 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -84,19 +84,24 @@ 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 { @@ -110,6 +115,7 @@ struct ima_digest_data { } ng; u8 data[2]; } xattr; + ); u8 digest[]; } __packed; @@ -118,7 +124,7 @@ 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;