diff options
Diffstat (limited to 'security/integrity/ima/ima_template_lib.c')
| -rw-r--r-- | security/integrity/ima/ima_template_lib.c | 745 |
1 files changed, 745 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c new file mode 100644 index 000000000..6cd0add52 --- /dev/null +++ b/security/integrity/ima/ima_template_lib.c @@ -0,0 +1,745 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2013 Politecnico di Torino, Italy + * TORSEC group -- https://security.polito.it + * + * Author: Roberto Sassu <roberto.sassu@polito.it> + * + * File: ima_template_lib.c + * Library of supported template fields. + */ + +#include "ima_template_lib.h" +#include <linux/xattr.h> +#include <linux/evm.h> + +static bool ima_template_hash_algo_allowed(u8 algo) +{ + if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5) + return true; + + return false; +} + +enum data_formats { + DATA_FMT_DIGEST = 0, + DATA_FMT_DIGEST_WITH_ALGO, + DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO, + DATA_FMT_STRING, + DATA_FMT_HEX, + DATA_FMT_UINT +}; + +enum digest_type { + DIGEST_TYPE_IMA, + DIGEST_TYPE_VERITY, + DIGEST_TYPE__LAST +}; + +#define DIGEST_TYPE_NAME_LEN_MAX 7 /* including NUL */ +static const char * const digest_type_name[DIGEST_TYPE__LAST] = { + [DIGEST_TYPE_IMA] = "ima", + [DIGEST_TYPE_VERITY] = "verity" +}; + +static int ima_write_template_field_data(const void *data, const u32 datalen, + enum data_formats datafmt, + struct ima_field_data *field_data) +{ + u8 *buf, *buf_ptr; + u32 buflen = datalen; + + if (datafmt == DATA_FMT_STRING) + buflen = datalen + 1; + + buf = kzalloc(buflen, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + memcpy(buf, data, datalen); + + /* + * Replace all space characters with underscore for event names and + * strings. This avoid that, during the parsing of a measurements list, + * filenames with spaces or that end with the suffix ' (deleted)' are + * split into multiple template fields (the space is the delimitator + * character for measurements lists in ASCII format). + */ + if (datafmt == DATA_FMT_STRING) { + for (buf_ptr = buf; buf_ptr - buf < datalen; buf_ptr++) + if (*buf_ptr == ' ') + *buf_ptr = '_'; + } + + field_data->data = buf; + field_data->len = buflen; + return 0; +} + +static void ima_show_template_data_ascii(struct seq_file *m, + enum ima_show_type show, + enum data_formats datafmt, + struct ima_field_data *field_data) +{ + u8 *buf_ptr = field_data->data; + u32 buflen = field_data->len; + + switch (datafmt) { + case DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO: + case DATA_FMT_DIGEST_WITH_ALGO: + buf_ptr = strrchr(field_data->data, ':'); + if (buf_ptr != field_data->data) + seq_printf(m, "%s", field_data->data); + + /* skip ':' and '\0' */ + buf_ptr += 2; + buflen -= buf_ptr - field_data->data; + fallthrough; + case DATA_FMT_DIGEST: + case DATA_FMT_HEX: + if (!buflen) + break; + ima_print_digest(m, buf_ptr, buflen); + break; + case DATA_FMT_STRING: + seq_printf(m, "%s", buf_ptr); + break; + case DATA_FMT_UINT: + switch (field_data->len) { + case sizeof(u8): + seq_printf(m, "%u", *(u8 *)buf_ptr); + break; + case sizeof(u16): + if (ima_canonical_fmt) + seq_printf(m, "%u", + le16_to_cpu(*(__le16 *)buf_ptr)); + else + seq_printf(m, "%u", *(u16 *)buf_ptr); + break; + case sizeof(u32): + if (ima_canonical_fmt) + seq_printf(m, "%u", + le32_to_cpu(*(__le32 *)buf_ptr)); + else + seq_printf(m, "%u", *(u32 *)buf_ptr); + break; + case sizeof(u64): + if (ima_canonical_fmt) + seq_printf(m, "%llu", + le64_to_cpu(*(__le64 *)buf_ptr)); + else + seq_printf(m, "%llu", *(u64 *)buf_ptr); + break; + default: + break; + } + break; + default: + break; + } +} + +static void ima_show_template_data_binary(struct seq_file *m, + enum ima_show_type show, + enum data_formats datafmt, + struct ima_field_data *field_data) +{ + u32 len = (show == IMA_SHOW_BINARY_OLD_STRING_FMT) ? + strlen(field_data->data) : field_data->len; + + if (show != IMA_SHOW_BINARY_NO_FIELD_LEN) { + u32 field_len = !ima_canonical_fmt ? + len : (__force u32)cpu_to_le32(len); + + ima_putc(m, &field_len, sizeof(field_len)); + } + + if (!len) + return; + + ima_putc(m, field_data->data, len); +} + +static void ima_show_template_field_data(struct seq_file *m, + enum ima_show_type show, + enum data_formats datafmt, + struct ima_field_data *field_data) +{ + switch (show) { + case IMA_SHOW_ASCII: + ima_show_template_data_ascii(m, show, datafmt, field_data); + break; + case IMA_SHOW_BINARY: + case IMA_SHOW_BINARY_NO_FIELD_LEN: + case IMA_SHOW_BINARY_OLD_STRING_FMT: + ima_show_template_data_binary(m, show, datafmt, field_data); + break; + default: + break; + } +} + +void ima_show_template_digest(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data) +{ + ima_show_template_field_data(m, show, DATA_FMT_DIGEST, field_data); +} + +void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data) +{ + ima_show_template_field_data(m, show, DATA_FMT_DIGEST_WITH_ALGO, + field_data); +} + +void ima_show_template_digest_ngv2(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data) +{ + ima_show_template_field_data(m, show, + DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO, + field_data); +} + +void ima_show_template_string(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data) +{ + 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); +} + +void ima_show_template_buf(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); +} + +void ima_show_template_uint(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data) +{ + ima_show_template_field_data(m, show, DATA_FMT_UINT, field_data); +} + +/** + * ima_parse_buf() - Parses lengths and data from an input buffer + * @bufstartp: Buffer start address. + * @bufendp: Buffer end address. + * @bufcurp: Pointer to remaining (non-parsed) data. + * @maxfields: Length of fields array. + * @fields: Array containing lengths and pointers of parsed data. + * @curfields: Number of array items containing parsed data. + * @len_mask: Bitmap (if bit is set, data length should not be parsed). + * @enforce_mask: Check if curfields == maxfields and/or bufcurp == bufendp. + * @bufname: String identifier of the input buffer. + * + * Return: 0 on success, -EINVAL on error. + */ +int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp, + int maxfields, struct ima_field_data *fields, int *curfields, + unsigned long *len_mask, int enforce_mask, char *bufname) +{ + void *bufp = bufstartp; + int i; + + for (i = 0; i < maxfields; i++) { + if (len_mask == NULL || !test_bit(i, len_mask)) { + if (bufp > (bufendp - sizeof(u32))) + break; + + if (ima_canonical_fmt) + fields[i].len = le32_to_cpu(*(__le32 *)bufp); + else + fields[i].len = *(u32 *)bufp; + + bufp += sizeof(u32); + } + + if (bufp > (bufendp - fields[i].len)) + break; + + fields[i].data = bufp; + bufp += fields[i].len; + } + + if ((enforce_mask & ENFORCE_FIELDS) && i != maxfields) { + pr_err("%s: nr of fields mismatch: expected: %d, current: %d\n", + bufname, maxfields, i); + return -EINVAL; + } + + if ((enforce_mask & ENFORCE_BUFEND) && bufp != bufendp) { + pr_err("%s: buf end mismatch: expected: %p, current: %p\n", + bufname, bufendp, bufp); + return -EINVAL; + } + + if (curfields) + *curfields = i; + + if (bufcurp) + *bufcurp = bufp; + + return 0; +} + +static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize, + u8 digest_type, u8 hash_algo, + struct ima_field_data *field_data) +{ + /* + * digest formats: + * - DATA_FMT_DIGEST: digest + * - DATA_FMT_DIGEST_WITH_ALGO: <hash algo> + ':' + '\0' + digest, + * - DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO: + * <digest type> + ':' + <hash algo> + ':' + '\0' + digest, + * + * where 'DATA_FMT_DIGEST' is the original digest format ('d') + * with a hash size limitation of 20 bytes, + * where <digest type> is either "ima" or "verity", + * where <hash algo> is the hash_algo_name[] string. + */ + u8 buffer[DIGEST_TYPE_NAME_LEN_MAX + CRYPTO_MAX_ALG_NAME + 2 + + IMA_MAX_DIGEST_SIZE] = { 0 }; + enum data_formats fmt = DATA_FMT_DIGEST; + u32 offset = 0; + + if (digest_type < DIGEST_TYPE__LAST && hash_algo < HASH_ALGO__LAST) { + fmt = DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO; + offset += 1 + sprintf(buffer, "%s:%s:", + digest_type_name[digest_type], + hash_algo_name[hash_algo]); + } else if (hash_algo < HASH_ALGO__LAST) { + fmt = DATA_FMT_DIGEST_WITH_ALGO; + offset += 1 + sprintf(buffer, "%s:", + hash_algo_name[hash_algo]); + } + + if (digest) + memcpy(buffer + offset, digest, digestsize); + else + /* + * If digest is NULL, the event being recorded is a violation. + * Make room for the digest by increasing the offset by the + * hash algorithm digest size. + */ + offset += hash_digest_size[hash_algo]; + + return ima_write_template_field_data(buffer, offset + digestsize, + fmt, field_data); +} + +/* + * This function writes the digest of an event (with size limit). + */ +int ima_eventdigest_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + struct ima_max_digest_data hash; + u8 *cur_digest = NULL; + u32 cur_digestsize = 0; + struct inode *inode; + int result; + + memset(&hash, 0, sizeof(hash)); + + if (event_data->violation) /* recording a violation. */ + goto out; + + if (ima_template_hash_algo_allowed(event_data->iint->ima_hash->algo)) { + cur_digest = event_data->iint->ima_hash->digest; + cur_digestsize = event_data->iint->ima_hash->length; + goto out; + } + + 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); + + /* algo can change depending on available PCR banks */ + if (!result && hash.hdr.algo != HASH_ALGO_SHA1) + result = -EINVAL; + + if (result < 0) + memset(&hash, 0, sizeof(hash)); + } + + cur_digest = hash.hdr.digest; + cur_digestsize = hash_digest_size[HASH_ALGO_SHA1]; + goto out; + } + + if (!event_data->file) /* missing info to re-calculate the digest */ + return -EINVAL; + + 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); + 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_digestsize = hash.hdr.length; +out: + return ima_eventdigest_init_common(cur_digest, cur_digestsize, + DIGEST_TYPE__LAST, HASH_ALGO__LAST, + field_data); +} + +/* + * This function writes the digest of an event (without size limit). + */ +int ima_eventdigest_ng_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + u8 *cur_digest = NULL, hash_algo = ima_hash_algo; + u32 cur_digestsize = 0; + + if (event_data->violation) /* recording a violation. */ + goto out; + + cur_digest = event_data->iint->ima_hash->digest; + cur_digestsize = event_data->iint->ima_hash->length; + + hash_algo = event_data->iint->ima_hash->algo; +out: + return ima_eventdigest_init_common(cur_digest, cur_digestsize, + DIGEST_TYPE__LAST, hash_algo, + field_data); +} + +/* + * This function writes the digest of an event (without size limit), + * prefixed with both the digest type and hash algorithm. + */ +int ima_eventdigest_ngv2_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + u8 *cur_digest = NULL, hash_algo = ima_hash_algo; + u32 cur_digestsize = 0; + u8 digest_type = DIGEST_TYPE_IMA; + + if (event_data->violation) /* recording a violation. */ + goto out; + + cur_digest = event_data->iint->ima_hash->digest; + cur_digestsize = event_data->iint->ima_hash->length; + + hash_algo = event_data->iint->ima_hash->algo; + if (event_data->iint->flags & IMA_VERITY_REQUIRED) + digest_type = DIGEST_TYPE_VERITY; +out: + return ima_eventdigest_init_common(cur_digest, cur_digestsize, + digest_type, hash_algo, + field_data); +} + +/* + * This function writes the digest of the file which is expected to match the + * digest contained in the file's appended signature. + */ +int ima_eventdigest_modsig_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + enum hash_algo hash_algo; + const u8 *cur_digest; + u32 cur_digestsize; + + if (!event_data->modsig) + return 0; + + if (event_data->violation) { + /* Recording a violation. */ + hash_algo = HASH_ALGO_SHA1; + cur_digest = NULL; + cur_digestsize = 0; + } else { + int rc; + + rc = ima_get_modsig_digest(event_data->modsig, &hash_algo, + &cur_digest, &cur_digestsize); + if (rc) + return rc; + else if (hash_algo == HASH_ALGO__LAST || cur_digestsize == 0) + /* There was some error collecting the digest. */ + return -EINVAL; + } + + return ima_eventdigest_init_common(cur_digest, cur_digestsize, + DIGEST_TYPE__LAST, hash_algo, + field_data); +} + +static int ima_eventname_init_common(struct ima_event_data *event_data, + struct ima_field_data *field_data, + bool size_limit) +{ + const char *cur_filename = NULL; + u32 cur_filename_len = 0; + + BUG_ON(event_data->filename == NULL && event_data->file == NULL); + + if (event_data->filename) { + cur_filename = event_data->filename; + cur_filename_len = strlen(event_data->filename); + + if (!size_limit || cur_filename_len <= IMA_EVENT_NAME_LEN_MAX) + goto out; + } + + if (event_data->file) { + cur_filename = event_data->file->f_path.dentry->d_name.name; + cur_filename_len = strlen(cur_filename); + } else + /* + * Truncate filename if the latter is too long and + * the file descriptor is not available. + */ + cur_filename_len = IMA_EVENT_NAME_LEN_MAX; +out: + return ima_write_template_field_data(cur_filename, cur_filename_len, + DATA_FMT_STRING, field_data); +} + +/* + * This function writes the name of an event (with size limit). + */ +int ima_eventname_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + return ima_eventname_init_common(event_data, field_data, true); +} + +/* + * This function writes the name of an event (without size limit). + */ +int ima_eventname_ng_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + return ima_eventname_init_common(event_data, field_data, false); +} + +/* + * ima_eventsig_init - include the file signature as part of the template data + */ +int ima_eventsig_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + struct evm_ima_xattr_data *xattr_value = event_data->xattr_value; + + if (!xattr_value || + (xattr_value->type != EVM_IMA_XATTR_DIGSIG && + xattr_value->type != IMA_VERITY_DIGSIG)) + return ima_eventevmsig_init(event_data, field_data); + + return ima_write_template_field_data(xattr_value, event_data->xattr_len, + DATA_FMT_HEX, field_data); +} + +/* + * ima_eventbuf_init - include the buffer(kexec-cmldine) as part of the + * template data. + */ +int ima_eventbuf_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + if ((!event_data->buf) || (event_data->buf_len == 0)) + return 0; + + return ima_write_template_field_data(event_data->buf, + event_data->buf_len, DATA_FMT_HEX, + field_data); +} + +/* + * ima_eventmodsig_init - include the appended file signature as part of the + * template data + */ +int ima_eventmodsig_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + const void *data; + u32 data_len; + int rc; + + if (!event_data->modsig) + return 0; + + /* + * modsig is a runtime structure containing pointers. Get its raw data + * instead. + */ + rc = ima_get_raw_modsig(event_data->modsig, &data, &data_len); + if (rc) + return rc; + + return ima_write_template_field_data(data, data_len, DATA_FMT_HEX, + field_data); +} + +/* + * ima_eventevmsig_init - include the EVM portable signature as part of the + * template data + */ +int ima_eventevmsig_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + struct evm_ima_xattr_data *xattr_data = NULL; + int rc = 0; + + if (!event_data->file) + return 0; + + rc = vfs_getxattr_alloc(&nop_mnt_idmap, file_dentry(event_data->file), + XATTR_NAME_EVM, (char **)&xattr_data, 0, + GFP_NOFS); + if (rc <= 0 || xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) { + rc = 0; + goto out; + } + + rc = ima_write_template_field_data((char *)xattr_data, rc, DATA_FMT_HEX, + field_data); + +out: + kfree(xattr_data); + return rc; +} + +static int ima_eventinodedac_init_common(struct ima_event_data *event_data, + struct ima_field_data *field_data, + bool get_uid) +{ + unsigned int id; + + if (!event_data->file) + return 0; + + if (get_uid) + id = i_uid_read(file_inode(event_data->file)); + else + id = i_gid_read(file_inode(event_data->file)); + + if (ima_canonical_fmt) { + if (sizeof(id) == sizeof(u16)) + id = (__force u16)cpu_to_le16(id); + else + id = (__force u32)cpu_to_le32(id); + } + + return ima_write_template_field_data((void *)&id, sizeof(id), + DATA_FMT_UINT, field_data); +} + +/* + * ima_eventinodeuid_init - include the inode UID as part of the template + * data + */ +int ima_eventinodeuid_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + return ima_eventinodedac_init_common(event_data, field_data, true); +} + +/* + * ima_eventinodegid_init - include the inode GID as part of the template + * data + */ +int ima_eventinodegid_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + return ima_eventinodedac_init_common(event_data, field_data, false); +} + +/* + * ima_eventinodemode_init - include the inode mode as part of the template + * data + */ +int ima_eventinodemode_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + struct inode *inode; + u16 mode; + + if (!event_data->file) + return 0; + + inode = file_inode(event_data->file); + mode = inode->i_mode; + if (ima_canonical_fmt) + mode = (__force u16)cpu_to_le16(mode); + + return ima_write_template_field_data((char *)&mode, sizeof(mode), + DATA_FMT_UINT, field_data); +} + +static int ima_eventinodexattrs_init_common(struct ima_event_data *event_data, + struct ima_field_data *field_data, + char type) +{ + u8 *buffer = NULL; + int rc; + + if (!event_data->file) + return 0; + + rc = evm_read_protected_xattrs(file_dentry(event_data->file), NULL, 0, + type, ima_canonical_fmt); + if (rc < 0) + return 0; + + buffer = kmalloc(rc, GFP_KERNEL); + if (!buffer) + return 0; + + rc = evm_read_protected_xattrs(file_dentry(event_data->file), buffer, + rc, type, ima_canonical_fmt); + if (rc < 0) { + rc = 0; + goto out; + } + + rc = ima_write_template_field_data((char *)buffer, rc, DATA_FMT_HEX, + field_data); +out: + kfree(buffer); + return rc; +} + +/* + * ima_eventinodexattrnames_init - include a list of xattr names as part of the + * template data + */ +int ima_eventinodexattrnames_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + return ima_eventinodexattrs_init_common(event_data, field_data, 'n'); +} + +/* + * ima_eventinodexattrlengths_init - include a list of xattr lengths as part of + * the template data + */ +int ima_eventinodexattrlengths_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + return ima_eventinodexattrs_init_common(event_data, field_data, 'l'); +} + +/* + * ima_eventinodexattrvalues_init - include a list of xattr values as part of + * the template data + */ +int ima_eventinodexattrvalues_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + return ima_eventinodexattrs_init_common(event_data, field_data, 'v'); +} |