diff options
Diffstat (limited to 'security/integrity/ima')
| -rw-r--r-- | security/integrity/ima/Kconfig | 16 | ||||
| -rw-r--r-- | security/integrity/ima/Makefile | 1 | ||||
| -rw-r--r-- | security/integrity/ima/ima.h | 39 | ||||
| -rw-r--r-- | security/integrity/ima/ima_api.c | 86 | ||||
| -rw-r--r-- | security/integrity/ima/ima_appraise.c | 263 | ||||
| -rw-r--r-- | security/integrity/ima/ima_crypto.c | 8 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 93 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 195 |
8 files changed, 601 insertions, 100 deletions
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index b9c1219924f..d232c73647a 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -11,6 +11,7 @@ config IMA select CRYPTO_SHA1 select TCG_TPM if HAS_IOMEM && !UML select TCG_TIS if TCG_TPM && X86 + select TCG_IBMVTPM if TCG_TPM && PPC64 help The Trusted Computing Group(TCG) runtime Integrity Measurement Architecture(IMA) maintains a list of hash @@ -55,3 +56,18 @@ config IMA_LSM_RULES default y help Disabling this option will disregard LSM based policy rules. + +config IMA_APPRAISE + bool "Appraise integrity measurements" + depends on IMA + default n + help + This option enables local measurement integrity appraisal. + It requires the system to be labeled with a security extended + attribute containing the file hash measurement. To protect + the security extended attributes from offline attack, enable + and configure EVM. + + For more information on integrity appraisal refer to: + <http://linux-ima.sourceforge.net> + If unsure, say N. diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index 5f740f6971e..3f2ca6bdc38 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_IMA) += ima.o ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \ ima_policy.o ima-$(CONFIG_IMA_AUDIT) += ima_audit.o +ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index e7c99fd0d22..8180adde10b 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -40,6 +40,7 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 }; extern int ima_initialized; extern int ima_used_chip; extern char *ima_hash; +extern int ima_appraise; /* IMA inode template definition */ struct ima_template_data { @@ -107,11 +108,14 @@ static inline unsigned long ima_hash_key(u8 *digest) } /* LIM API function definitions */ +int ima_get_action(struct inode *inode, int mask, int function); int ima_must_measure(struct inode *inode, int mask, int function); int ima_collect_measurement(struct integrity_iint_cache *iint, struct file *file); void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, const unsigned char *filename); +void ima_audit_measurement(struct integrity_iint_cache *iint, + const unsigned char *filename); int ima_store_template(struct ima_template_entry *entry, int violation, struct inode *inode); void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show); @@ -123,14 +127,45 @@ struct integrity_iint_cache *integrity_iint_insert(struct inode *inode); struct integrity_iint_cache *integrity_iint_find(struct inode *inode); /* IMA policy related functions */ -enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK }; +enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK, POST_SETATTR }; -int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask); +int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, + int flags); void ima_init_policy(void); void ima_update_policy(void); ssize_t ima_parse_add_rule(char *); void ima_delete_rules(void); +/* Appraise integrity measurements */ +#define IMA_APPRAISE_ENFORCE 0x01 +#define IMA_APPRAISE_FIX 0x02 + +#ifdef CONFIG_IMA_APPRAISE +int ima_appraise_measurement(struct integrity_iint_cache *iint, + struct file *file, const unsigned char *filename); +int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask); +void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file); + +#else +static inline int ima_appraise_measurement(struct integrity_iint_cache *iint, + struct file *file, + const unsigned char *filename) +{ + return INTEGRITY_UNKNOWN; +} + +static inline int ima_must_appraise(struct inode *inode, + enum ima_hooks func, int mask) +{ + return 0; +} + +static inline void ima_update_xattr(struct integrity_iint_cache *iint, + struct file *file) +{ +} +#endif + /* LSM based policy rules require audit */ #ifdef CONFIG_IMA_LSM_RULES diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index 032ff03ad90..b356884fb3e 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -9,13 +9,17 @@ * License. * * File: ima_api.c - * Implements must_measure, collect_measurement, store_measurement, - * and store_template. + * Implements must_appraise_or_measure, collect_measurement, + * appraise_measurement, store_measurement and store_template. */ #include <linux/module.h> #include <linux/slab.h> - +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/xattr.h> +#include <linux/evm.h> #include "ima.h" + static const char *IMA_TEMPLATE_NAME = "ima"; /* @@ -93,7 +97,7 @@ err_out: } /** - * ima_must_measure - measure decision based on policy. + * ima_get_action - appraise & measure decision based on policy. * @inode: pointer to inode to measure * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE) * @function: calling function (FILE_CHECK, BPRM_CHECK, FILE_MMAP) @@ -105,15 +109,22 @@ err_out: * mask: contains the permission mask * fsmagic: hex value * - * Return 0 to measure. For matching a DONT_MEASURE policy, no policy, - * or other error, return an error code. -*/ -int ima_must_measure(struct inode *inode, int mask, int function) + * Returns IMA_MEASURE, IMA_APPRAISE mask. + * + */ +int ima_get_action(struct inode *inode, int mask, int function) { - int must_measure; + int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE; + + if (!ima_appraise) + flags &= ~IMA_APPRAISE; - must_measure = ima_match_policy(inode, function, mask); - return must_measure ? 0 : -EACCES; + return ima_match_policy(inode, function, mask, flags); +} + +int ima_must_measure(struct inode *inode, int mask, int function) +{ + return ima_match_policy(inode, function, mask, IMA_MEASURE); } /* @@ -129,16 +140,24 @@ int ima_must_measure(struct inode *inode, int mask, int function) int ima_collect_measurement(struct integrity_iint_cache *iint, struct file *file) { - int result = -EEXIST; + struct inode *inode = file->f_dentry->d_inode; + const char *filename = file->f_dentry->d_name.name; + int result = 0; - if (!(iint->flags & IMA_MEASURED)) { + if (!(iint->flags & IMA_COLLECTED)) { u64 i_version = file->f_dentry->d_inode->i_version; - memset(iint->digest, 0, IMA_DIGEST_SIZE); - result = ima_calc_hash(file, iint->digest); - if (!result) + iint->ima_xattr.type = IMA_XATTR_DIGEST; + result = ima_calc_hash(file, iint->ima_xattr.digest); + if (!result) { iint->version = i_version; + iint->flags |= IMA_COLLECTED; + } } + if (result) + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, + filename, "collect_data", "failed", + result, 0); return result; } @@ -167,6 +186,9 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct ima_template_entry *entry; int violation = 0; + if (iint->flags & IMA_MEASURED) + return; + entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) { integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename, @@ -174,7 +196,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, return; } memset(&entry->template, 0, sizeof(entry->template)); - memcpy(entry->template.digest, iint->digest, IMA_DIGEST_SIZE); + memcpy(entry->template.digest, iint->ima_xattr.digest, IMA_DIGEST_SIZE); strcpy(entry->template.file_name, (strlen(filename) > IMA_EVENT_NAME_LEN_MAX) ? file->f_dentry->d_name.name : filename); @@ -185,3 +207,33 @@ void ima_store_measurement(struct integrity_iint_cache *iint, if (result < 0) kfree(entry); } + +void ima_audit_measurement(struct integrity_iint_cache *iint, + const unsigned char *filename) +{ + struct audit_buffer *ab; + char hash[(IMA_DIGEST_SIZE * 2) + 1]; + int i; + + if (iint->flags & IMA_AUDITED) + return; + + for (i = 0; i < IMA_DIGEST_SIZE; i++) + hex_byte_pack(hash + (i * 2), iint->ima_xattr.digest[i]); + hash[i * 2] = '\0'; + + ab = audit_log_start(current->audit_context, GFP_KERNEL, + AUDIT_INTEGRITY_RULE); + if (!ab) + return; + + audit_log_format(ab, "file="); + audit_log_untrustedstring(ab, filename); + audit_log_format(ab, " hash="); + audit_log_untrustedstring(ab, hash); + + audit_log_task_info(ab, current); + audit_log_end(ab); + + iint->flags |= IMA_AUDITED; +} diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c new file mode 100644 index 00000000000..0aa43bde441 --- /dev/null +++ b/security/integrity/ima/ima_appraise.c @@ -0,0 +1,263 @@ +/* + * Copyright (C) 2011 IBM Corporation + * + * Author: + * Mimi Zohar <zohar@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + */ +#include <linux/module.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/xattr.h> +#include <linux/magic.h> +#include <linux/ima.h> +#include <linux/evm.h> + +#include "ima.h" + +static int __init default_appraise_setup(char *str) +{ + if (strncmp(str, "off", 3) == 0) + ima_appraise = 0; + else if (strncmp(str, "fix", 3) == 0) + ima_appraise = IMA_APPRAISE_FIX; + return 1; +} + +__setup("ima_appraise=", default_appraise_setup); + +/* + * ima_must_appraise - set appraise flag + * + * Return 1 to appraise + */ +int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask) +{ + if (!ima_appraise) + return 0; + + return ima_match_policy(inode, func, mask, IMA_APPRAISE); +} + +static void ima_fix_xattr(struct dentry *dentry, + struct integrity_iint_cache *iint) +{ + iint->ima_xattr.type = IMA_XATTR_DIGEST; + __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA, (u8 *)&iint->ima_xattr, + sizeof iint->ima_xattr, 0); +} + +/* + * ima_appraise_measurement - appraise file measurement + * + * Call evm_verifyxattr() to verify the integrity of 'security.ima'. + * Assuming success, compare the xattr hash with the collected measurement. + * + * Return 0 on success, error code otherwise + */ +int ima_appraise_measurement(struct integrity_iint_cache *iint, + struct file *file, const unsigned char *filename) +{ + struct dentry *dentry = file->f_dentry; + struct inode *inode = dentry->d_inode; + struct evm_ima_xattr_data *xattr_value = NULL; + enum integrity_status status = INTEGRITY_UNKNOWN; + const char *op = "appraise_data"; + char *cause = "unknown"; + int rc; + + if (!ima_appraise) + return 0; + if (!inode->i_op->getxattr) + return INTEGRITY_UNKNOWN; + + if (iint->flags & IMA_APPRAISED) + return iint->ima_status; + + rc = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)&xattr_value, + 0, GFP_NOFS); + if (rc <= 0) { + if (rc && rc != -ENODATA) + goto out; + + cause = "missing-hash"; + status = + (inode->i_size == 0) ? INTEGRITY_PASS : INTEGRITY_NOLABEL; + goto out; + } + + status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint); + if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) { + if ((status == INTEGRITY_NOLABEL) + || (status == INTEGRITY_NOXATTRS)) + cause = "missing-HMAC"; + else if (status == INTEGRITY_FAIL) + cause = "invalid-HMAC"; + goto out; + } + + switch (xattr_value->type) { + case IMA_XATTR_DIGEST: + rc = memcmp(xattr_value->digest, iint->ima_xattr.digest, + IMA_DIGEST_SIZE); + if (rc) { + cause = "invalid-hash"; + status = INTEGRITY_FAIL; + print_hex_dump_bytes("security.ima: ", DUMP_PREFIX_NONE, + xattr_value, sizeof(*xattr_value)); + print_hex_dump_bytes("collected: ", DUMP_PREFIX_NONE, + (u8 *)&iint->ima_xattr, + sizeof iint->ima_xattr); + break; + } + status = INTEGRITY_PASS; + break; + case EVM_IMA_XATTR_DIGSIG: + iint->flags |= IMA_DIGSIG; + rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, + xattr_value->digest, rc - 1, + iint->ima_xattr.digest, + IMA_DIGEST_SIZE); + if (rc == -EOPNOTSUPP) { + status = INTEGRITY_UNKNOWN; + } else if (rc) { + cause = "invalid-signature"; + status = INTEGRITY_FAIL; + } else { + status = INTEGRITY_PASS; + } + break; + default: + status = INTEGRITY_UNKNOWN; + cause = "unknown-ima-data"; + break; + } + +out: + if (status != INTEGRITY_PASS) { + if ((ima_appraise & IMA_APPRAISE_FIX) && + (!xattr_value || + xattr_value->type != EVM_IMA_XATTR_DIGSIG)) { + ima_fix_xattr(dentry, iint); + status = INTEGRITY_PASS; + } + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, + op, cause, rc, 0); + } else { + iint->flags |= IMA_APPRAISED; + } + iint->ima_status = status; + kfree(xattr_value); + return status; +} + +/* + * ima_update_xattr - update 'security.ima' hash value + */ +void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file) +{ + struct dentry *dentry = file->f_dentry; + int rc = 0; + + /* do not collect and update hash for digital signatures */ + if (iint->flags & IMA_DIGSIG) + return; + + rc = ima_collect_measurement(iint, file); + if (rc < 0) + return; + + ima_fix_xattr(dentry, iint); +} + +/** + * ima_inode_post_setattr - reflect file metadata changes + * @dentry: pointer to the affected dentry + * + * Changes to a dentry's metadata might result in needing to appraise. + * + * This function is called from notify_change(), which expects the caller + * to lock the inode's i_mutex. + */ +void ima_inode_post_setattr(struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + struct integrity_iint_cache *iint; + int must_appraise, rc; + + if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode) + || !inode->i_op->removexattr) + return; + + must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR); + iint = integrity_iint_find(inode); + if (iint) { + if (must_appraise) + iint->flags |= IMA_APPRAISE; + else + iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED); + } + if (!must_appraise) + rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA); + return; +} + +/* + * ima_protect_xattr - protect 'security.ima' + * + * Ensure that not just anyone can modify or remove 'security.ima'. + */ +static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) { + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + return 1; + } + return 0; +} + +static void ima_reset_appraise_flags(struct inode *inode) +{ + struct integrity_iint_cache *iint; + + if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode)) + return; + + iint = integrity_iint_find(inode); + if (!iint) + return; + + iint->flags &= ~IMA_DONE_MASK; + return; +} + +int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len) +{ + int result; + + result = ima_protect_xattr(dentry, xattr_name, xattr_value, + xattr_value_len); + if (result == 1) { + ima_reset_appraise_flags(dentry->d_inode); + result = 0; + } + return result; +} + +int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name) +{ + int result; + + result = ima_protect_xattr(dentry, xattr_name, NULL, 0); + if (result == 1) { + ima_reset_appraise_flags(dentry->d_inode); + result = 0; + } + return result; +} diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index 9b3ade7468b..b21ee5b5495 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -48,7 +48,7 @@ int ima_calc_hash(struct file *file, char *digest) struct scatterlist sg[1]; loff_t i_size, offset = 0; char *rbuf; - int rc; + int rc, read = 0; rc = init_desc(&desc); if (rc != 0) @@ -59,6 +59,10 @@ int ima_calc_hash(struct file *file, char *digest) rc = -ENOMEM; goto out; } + if (!(file->f_mode & FMODE_READ)) { + file->f_mode |= FMODE_READ; + read = 1; + } i_size = i_size_read(file->f_dentry->d_inode); while (offset < i_size) { int rbuf_len; @@ -80,6 +84,8 @@ int ima_calc_hash(struct file *file, char *digest) kfree(rbuf); if (!rc) rc = crypto_hash_final(&desc, digest); + if (read) + file->f_mode &= ~FMODE_READ; out: crypto_free_hash(desc.tfm); return rc; diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index be8294915cf..73c9a268253 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -22,12 +22,19 @@ #include <linux/mount.h> #include <linux/mman.h> #include <linux/slab.h> +#include <linux/xattr.h> #include <linux/ima.h> #include "ima.h" int ima_initialized; +#ifdef CONFIG_IMA_APPRAISE +int ima_appraise = IMA_APPRAISE_ENFORCE; +#else +int ima_appraise; +#endif + char *ima_hash = "sha1"; static int __init hash_setup(char *str) { @@ -52,7 +59,7 @@ static void ima_rdwr_violation_check(struct file *file) struct dentry *dentry = file->f_path.dentry; struct inode *inode = dentry->d_inode; fmode_t mode = file->f_mode; - int rc; + int must_measure; bool send_tomtou = false, send_writers = false; unsigned char *pathname = NULL, *pathbuf = NULL; @@ -67,8 +74,8 @@ static void ima_rdwr_violation_check(struct file *file) goto out; } - rc = ima_must_measure(inode, MAY_READ, FILE_CHECK); - if (rc < 0) + must_measure = ima_must_measure(inode, MAY_READ, FILE_CHECK); + if (!must_measure) goto out; if (atomic_read(&inode->i_writecount) > 0) @@ -100,17 +107,21 @@ out: } static void ima_check_last_writer(struct integrity_iint_cache *iint, - struct inode *inode, - struct file *file) + struct inode *inode, struct file *file) { fmode_t mode = file->f_mode; - mutex_lock(&iint->mutex); - if (mode & FMODE_WRITE && - atomic_read(&inode->i_writecount) == 1 && - iint->version != inode->i_version) - iint->flags &= ~IMA_MEASURED; - mutex_unlock(&iint->mutex); + if (!(mode & FMODE_WRITE)) + return; + + mutex_lock(&inode->i_mutex); + if (atomic_read(&inode->i_writecount) == 1 && + iint->version != inode->i_version) { + iint->flags &= ~IMA_DONE_MASK; + if (iint->flags & IMA_APPRAISE) + ima_update_xattr(iint, file); + } + mutex_unlock(&inode->i_mutex); } /** @@ -140,28 +151,37 @@ static int process_measurement(struct file *file, const unsigned char *filename, struct inode *inode = file->f_dentry->d_inode; struct integrity_iint_cache *iint; unsigned char *pathname = NULL, *pathbuf = NULL; - int rc = 0; + int rc = -ENOMEM, action, must_appraise; if (!ima_initialized || !S_ISREG(inode->i_mode)) return 0; - rc = ima_must_measure(inode, mask, function); - if (rc != 0) - return rc; -retry: - iint = integrity_iint_find(inode); - if (!iint) { - rc = integrity_inode_alloc(inode); - if (!rc || rc == -EEXIST) - goto retry; - return rc; - } + /* Determine if in appraise/audit/measurement policy, + * returns IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT bitmask. */ + action = ima_get_action(inode, mask, function); + if (!action) + return 0; - mutex_lock(&iint->mutex); + must_appraise = action & IMA_APPRAISE; - rc = iint->flags & IMA_MEASURED ? 1 : 0; - if (rc != 0) + mutex_lock(&inode->i_mutex); + + iint = integrity_inode_get(inode); + if (!iint) + goto out; + + /* Determine if already appraised/measured based on bitmask + * (IMA_MEASURE, IMA_MEASURED, IMA_APPRAISE, IMA_APPRAISED, + * IMA_AUDIT, IMA_AUDITED) */ + iint->flags |= action; + action &= ~((iint->flags & IMA_DONE_MASK) >> 1); + + /* Nothing to do, just return existing appraised status */ + if (!action) { + if (iint->flags & IMA_APPRAISED) + rc = iint->ima_status; goto out; + } rc = ima_collect_measurement(iint, file); if (rc != 0) @@ -177,11 +197,18 @@ retry: pathname = NULL; } } - ima_store_measurement(iint, file, !pathname ? filename : pathname); + if (action & IMA_MEASURE) + ima_store_measurement(iint, file, + !pathname ? filename : pathname); + if (action & IMA_APPRAISE) + rc = ima_appraise_measurement(iint, file, + !pathname ? filename : pathname); + if (action & IMA_AUDIT) + ima_audit_measurement(iint, !pathname ? filename : pathname); kfree(pathbuf); out: - mutex_unlock(&iint->mutex); - return rc; + mutex_unlock(&inode->i_mutex); + return (rc && must_appraise) ? -EACCES : 0; } /** @@ -197,14 +224,14 @@ out: */ int ima_file_mmap(struct file *file, unsigned long prot) { - int rc; + int rc = 0; if (!file) return 0; if (prot & PROT_EXEC) rc = process_measurement(file, file->f_dentry->d_name.name, MAY_EXEC, FILE_MMAP); - return 0; + return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0; } /** @@ -228,7 +255,7 @@ int ima_bprm_check(struct linux_binprm *bprm) (strcmp(bprm->filename, bprm->interp) == 0) ? bprm->filename : bprm->interp, MAY_EXEC, BPRM_CHECK); - return 0; + return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0; } /** @@ -249,7 +276,7 @@ int ima_file_check(struct file *file, int mask) rc = process_measurement(file, file->f_dentry->d_name.name, mask & (MAY_READ | MAY_WRITE | MAY_EXEC), FILE_CHECK); - return 0; + return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0; } EXPORT_SYMBOL_GPL(ima_file_check); diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index c84df05180c..c7dacd2eab7 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -24,22 +24,29 @@ #define IMA_MASK 0x0002 #define IMA_FSMAGIC 0x0004 #define IMA_UID 0x0008 +#define IMA_FOWNER 0x0010 -enum ima_action { UNKNOWN = -1, DONT_MEASURE = 0, MEASURE }; +#define UNKNOWN 0 +#define MEASURE 0x0001 /* same as IMA_MEASURE */ +#define DONT_MEASURE 0x0002 +#define APPRAISE 0x0004 /* same as IMA_APPRAISE */ +#define DONT_APPRAISE 0x0008 +#define AUDIT 0x0040 #define MAX_LSM_RULES 6 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE }; -struct ima_measure_rule_entry { +struct ima_rule_entry { struct list_head list; - enum ima_action action; + int action; unsigned int flags; enum ima_hooks func; int mask; unsigned long fsmagic; kuid_t uid; + kuid_t fowner; struct { void *rule; /* LSM file metadata specific */ int type; /* audit type */ @@ -48,7 +55,7 @@ struct ima_measure_rule_entry { /* * Without LSM specific knowledge, the default policy can only be - * written in terms of .action, .func, .mask, .fsmagic, and .uid + * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner */ /* @@ -57,7 +64,7 @@ struct ima_measure_rule_entry { * normal users can easily run the machine out of memory simply building * and running executables. */ -static struct ima_measure_rule_entry default_rules[] = { +static struct ima_rule_entry default_rules[] = { {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, @@ -75,19 +82,41 @@ static struct ima_measure_rule_entry default_rules[] = { .flags = IMA_FUNC | IMA_MASK | IMA_UID}, }; -static LIST_HEAD(measure_default_rules); -static LIST_HEAD(measure_policy_rules); -static struct list_head *ima_measure; +static struct ima_rule_entry default_appraise_rules[] = { + {.action = DONT_APPRAISE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = CGROUP_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = APPRAISE,.fowner = GLOBAL_ROOT_UID,.flags = IMA_FOWNER}, +}; + +static LIST_HEAD(ima_default_rules); +static LIST_HEAD(ima_policy_rules); +static struct list_head *ima_rules; -static DEFINE_MUTEX(ima_measure_mutex); +static DEFINE_MUTEX(ima_rules_mutex); static bool ima_use_tcb __initdata; -static int __init default_policy_setup(char *str) +static int __init default_measure_policy_setup(char *str) { ima_use_tcb = 1; return 1; } -__setup("ima_tcb", default_policy_setup); +__setup("ima_tcb", default_measure_policy_setup); + +static bool ima_use_appraise_tcb __initdata; +static int __init default_appraise_policy_setup(char *str) +{ + ima_use_appraise_tcb = 1; + return 1; +} +__setup("ima_appraise_tcb", default_appraise_policy_setup); /** * ima_match_rules - determine whether an inode matches the measure rule. @@ -98,7 +127,7 @@ __setup("ima_tcb", default_policy_setup); * * Returns true on rule match, false on failure. */ -static bool ima_match_rules(struct ima_measure_rule_entry *rule, +static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, enum ima_hooks func, int mask) { struct task_struct *tsk = current; @@ -114,6 +143,8 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule, return false; if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid)) return false; + if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid)) + return false; for (i = 0; i < MAX_LSM_RULES; i++) { int rc = 0; u32 osid, sid; @@ -163,39 +194,61 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule, * as elements in the list are never deleted, nor does the list * change.) */ -int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask) +int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, + int flags) { - struct ima_measure_rule_entry *entry; + struct ima_rule_entry *entry; + int action = 0, actmask = flags | (flags << 1); + + list_for_each_entry(entry, ima_rules, list) { + + if (!(entry->action & actmask)) + continue; + + if (!ima_match_rules(entry, inode, func, mask)) + continue; - list_for_each_entry(entry, ima_measure, list) { - bool rc; + action |= entry->action & IMA_DO_MASK; + if (entry->action & IMA_DO_MASK) + actmask &= ~(entry->action | entry->action << 1); + else + actmask &= ~(entry->action | entry->action >> 1); - rc = ima_match_rules(entry, inode, func, mask); - if (rc) - return entry->action; + if (!actmask) + break; } - return 0; + + return action; } /** * ima_init_policy - initialize the default measure rules. * - * ima_measure points to either the measure_default_rules or the - * the new measure_policy_rules. + * ima_rules points to either the ima_default_rules or the + * the new ima_policy_rules. */ void __init ima_init_policy(void) { - int i, entries; + int i, measure_entries, appraise_entries; /* if !ima_use_tcb set entries = 0 so we load NO default rules */ - if (ima_use_tcb) - entries = ARRAY_SIZE(default_rules); - else - entries = 0; - - for (i = 0; i < entries; i++) - list_add_tail(&default_rules[i].list, &measure_default_rules); - ima_measure = &measure_default_rules; + measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0; + appraise_entries = ima_use_appraise_tcb ? + ARRAY_SIZE(default_appraise_rules) : 0; + + for (i = 0; i < measure_entries + appraise_entries; i++) { + if (i < measure_entries) + list_add_tail(&default_rules[i].list, + &ima_default_rules); + else { + int j = i - measure_entries; + + list_add_tail(&default_appraise_rules[j].list, + &ima_default_rules); + } + } + + ima_rules = &ima_default_rules; } /** @@ -212,8 +265,8 @@ void ima_update_policy(void) int result = 1; int audit_info = 0; - if (ima_measure == &measure_default_rules) { - ima_measure = &measure_policy_rules; + if (ima_rules == &ima_default_rules) { + ima_rules = &ima_policy_rules; cause = "complete"; result = 0; } @@ -224,14 +277,19 @@ void ima_update_policy(void) enum { Opt_err = -1, Opt_measure = 1, Opt_dont_measure, + Opt_appraise, Opt_dont_appraise, + Opt_audit, Opt_obj_user, Opt_obj_role, Opt_obj_type, Opt_subj_user, Opt_subj_role, Opt_subj_type, - Opt_func, Opt_mask, Opt_fsmagic, Opt_uid + Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner }; static match_table_t policy_tokens = { {Opt_measure, "measure"}, {Opt_dont_measure, "dont_measure"}, + {Opt_appraise, "appraise"}, + {Opt_dont_appraise, "dont_appraise"}, + {Opt_audit, "audit"}, {Opt_obj_user, "obj_user=%s"}, {Opt_obj_role, "obj_role=%s"}, {Opt_obj_type, "obj_type=%s"}, @@ -242,10 +300,11 @@ static match_table_t policy_tokens = { {Opt_mask, "mask=%s"}, {Opt_fsmagic, "fsmagic=%s"}, {Opt_uid, "uid=%s"}, + {Opt_fowner, "fowner=%s"}, {Opt_err, NULL} }; -static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry, +static int ima_lsm_rule_init(struct ima_rule_entry *entry, char *args, int lsm_rule, int audit_type) { int result; @@ -269,7 +328,7 @@ static void ima_log_string(struct audit_buffer *ab, char *key, char *value) audit_log_format(ab, " "); } -static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) +static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) { struct audit_buffer *ab; char *p; @@ -278,6 +337,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); entry->uid = INVALID_UID; + entry->fowner = INVALID_UID; entry->action = UNKNOWN; while ((p = strsep(&rule, " \t")) != NULL) { substring_t args[MAX_OPT_ARGS]; @@ -306,11 +366,35 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) entry->action = DONT_MEASURE; break; + case Opt_appraise: + ima_log_string(ab, "action", "appraise"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = APPRAISE; + break; + case Opt_dont_appraise: + ima_log_string(ab, "action", "dont_appraise"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = DONT_APPRAISE; + break; + case Opt_audit: + ima_log_string(ab, "action", "audit"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = AUDIT; + break; case Opt_func: ima_log_string(ab, "func", args[0].from); if (entry->func) - result = -EINVAL; + result = -EINVAL; if (strcmp(args[0].from, "FILE_CHECK") == 0) entry->func = FILE_CHECK; @@ -375,6 +459,23 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) entry->flags |= IMA_UID; } break; + case Opt_fowner: + ima_log_string(ab, "fowner", args[0].from); + + if (uid_valid(entry->fowner)) { + result = -EINVAL; + break; + } + + result = strict_strtoul(args[0].from, 10, &lnum); + if (!result) { + entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); + if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) + result = -EINVAL; + else + entry->flags |= IMA_FOWNER; + } + break; case Opt_obj_user: ima_log_string(ab, "obj_user", args[0].from); result = ima_lsm_rule_init(entry, args[0].from, @@ -426,7 +527,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) } /** - * ima_parse_add_rule - add a rule to measure_policy_rules + * ima_parse_add_rule - add a rule to ima_policy_rules * @rule - ima measurement policy rule * * Uses a mutex to protect the policy list from multiple concurrent writers. @@ -436,12 +537,12 @@ ssize_t ima_parse_add_rule(char *rule) { const char *op = "update_policy"; char *p; - struct ima_measure_rule_entry *entry; + struct ima_rule_entry *entry; ssize_t result, len; int audit_info = 0; /* Prevent installed policy from changing */ - if (ima_measure != &measure_default_rules) { + if (ima_rules != &ima_default_rules) { integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, op, "already exists", -EACCES, audit_info); @@ -474,9 +575,9 @@ ssize_t ima_parse_add_rule(char *rule) return result; } - mutex_lock(&ima_measure_mutex); - list_add_tail(&entry->list, &measure_policy_rules); - mutex_unlock(&ima_measure_mutex); + mutex_lock(&ima_rules_mutex); + list_add_tail(&entry->list, &ima_policy_rules); + mutex_unlock(&ima_rules_mutex); return len; } @@ -484,12 +585,12 @@ ssize_t ima_parse_add_rule(char *rule) /* ima_delete_rules called to cleanup invalid policy */ void ima_delete_rules(void) { - struct ima_measure_rule_entry *entry, *tmp; + struct ima_rule_entry *entry, *tmp; - mutex_lock(&ima_measure_mutex); - list_for_each_entry_safe(entry, tmp, &measure_policy_rules, list) { + mutex_lock(&ima_rules_mutex); + list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { list_del(&entry->list); kfree(entry); } - mutex_unlock(&ima_measure_mutex); + mutex_unlock(&ima_rules_mutex); } |