From cb1aa3823c9280f2bb8218cdb5cb05721e0376b1 Mon Sep 17 00:00:00 2001 From: Lakshmi Ramasubramanian Date: Wed, 11 Dec 2019 08:47:05 -0800 Subject: KEYS: Call the IMA hook to measure keys Call the IMA hook from key_create_or_update() function to measure the payload when a new key is created or an existing key is updated. This patch adds the call to the IMA hook from key_create_or_update() function to measure the key on key create or update. Signed-off-by: Lakshmi Ramasubramanian Cc: David Howells Cc: Jarkko Sakkinen Signed-off-by: Mimi Zohar --- include/linux/ima.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include/linux/ima.h') diff --git a/include/linux/ima.h b/include/linux/ima.h index 6d904754d858..3b89136bc218 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -101,6 +101,20 @@ static inline void ima_add_kexec_buffer(struct kimage *image) {} #endif +#if defined(CONFIG_IMA) && defined(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) +extern void ima_post_key_create_or_update(struct key *keyring, + struct key *key, + const void *payload, size_t plen, + unsigned long flags, bool create); +#else +static inline void ima_post_key_create_or_update(struct key *keyring, + struct key *key, + const void *payload, + size_t plen, + unsigned long flags, + bool create) {} +#endif /* CONFIG_IMA && CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE */ + #ifdef CONFIG_IMA_APPRAISE extern bool is_ima_appraise_enabled(void); extern void ima_inode_post_setattr(struct dentry *dentry); -- cgit v1.2.3 From ea78979d302f7de9bbd59f9dafdb070ecb05ec39 Mon Sep 17 00:00:00 2001 From: Lakshmi Ramasubramanian Date: Wed, 8 Jan 2020 08:05:08 -0800 Subject: IMA: fix measuring asymmetric keys Kconfig As a result of the asymmetric public keys subtype Kconfig option being defined as tristate, with the existing IMA Makefile, ima_asymmetric_keys.c could be built as a kernel module. To prevent this from happening, this patch defines and uses an intermediate Kconfig boolean option named IMA_MEASURE_ASYMMETRIC_KEYS. Signed-off-by: Lakshmi Ramasubramanian Suggested-by: James.Bottomley Cc: David Howells Cc: Jarkko Sakkinen Reported-by: kbuild test robot # ima_asymmetric_keys.c is built as a kernel module. Fixes: 88e70da170e8 ("IMA: Define an IMA hook to measure keys") Fixes: cb1aa3823c92 ("KEYS: Call the IMA hook to measure keys") [zohar@linux.ibm.com: updated patch description] Signed-off-by: Mimi Zohar --- include/linux/ima.h | 4 ++-- security/integrity/ima/Kconfig | 6 ++++++ security/integrity/ima/Makefile | 2 +- 3 files changed, 9 insertions(+), 3 deletions(-) (limited to 'include/linux/ima.h') diff --git a/include/linux/ima.h b/include/linux/ima.h index 3b89136bc218..f4644c54f648 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -101,7 +101,7 @@ static inline void ima_add_kexec_buffer(struct kimage *image) {} #endif -#if defined(CONFIG_IMA) && defined(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) +#ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS extern void ima_post_key_create_or_update(struct key *keyring, struct key *key, const void *payload, size_t plen, @@ -113,7 +113,7 @@ static inline void ima_post_key_create_or_update(struct key *keyring, size_t plen, unsigned long flags, bool create) {} -#endif /* CONFIG_IMA && CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE */ +#endif /* CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS */ #ifdef CONFIG_IMA_APPRAISE extern bool is_ima_appraise_enabled(void); diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 838476d780e5..355754a6b6ca 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -310,3 +310,9 @@ config IMA_APPRAISE_SIGNED_INIT default n help This option requires user-space init to be signed. + +config IMA_MEASURE_ASYMMETRIC_KEYS + bool + depends on IMA + depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE=y + default y diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index 207a0a9eb72c..3e9d0ad68c7b 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -12,4 +12,4 @@ ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o -obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += ima_asymmetric_keys.o +obj-$(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) += ima_asymmetric_keys.o -- cgit v1.2.3 From 6beea7afcc72b86986080ea1d228a42f2000f2a9 Mon Sep 17 00:00:00 2001 From: Florent Revest Date: Mon, 13 Jan 2020 10:42:44 +0100 Subject: ima: add the ability to query the cached hash of a given file This allows other parts of the kernel (perhaps a stacked LSM allowing system monitoring, eg. the proposed KRSI LSM [1]) to retrieve the hash of a given file from IMA if it's present in the iint cache. It's true that the existence of the hash means that it's also in the audit logs or in /sys/kernel/security/ima/ascii_runtime_measurements, but it can be difficult to pull that information out for every subsequent exec. This is especially true if a given host has been up for a long time and the file was first measured a long time ago. It should be kept in mind that this function gives access to cached entries which can be removed, for instance on security_inode_free(). This is based on Peter Moody's patch: https://sourceforge.net/p/linux-ima/mailman/message/33036180/ [1] https://lkml.org/lkml/2019/9/10/393 Signed-off-by: Florent Revest Reviewed-by: KP Singh Signed-off-by: Mimi Zohar --- include/linux/ima.h | 6 +++++ security/integrity/ima/ima_main.c | 49 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) (limited to 'include/linux/ima.h') diff --git a/include/linux/ima.h b/include/linux/ima.h index f4644c54f648..1659217e9b60 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -23,6 +23,7 @@ extern int ima_read_file(struct file *file, enum kernel_read_file_id id); extern int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id id); extern void ima_post_path_mknod(struct dentry *dentry); +extern int ima_file_hash(struct file *file, char *buf, size_t buf_size); extern void ima_kexec_cmdline(const void *buf, int size); #ifdef CONFIG_IMA_KEXEC @@ -91,6 +92,11 @@ static inline void ima_post_path_mknod(struct dentry *dentry) return; } +static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size) +{ + return -EOPNOTSUPP; +} + static inline void ima_kexec_cmdline(const void *buf, int size) {} #endif /* CONFIG_IMA */ diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 2272c3255c7d..9fe949c6a530 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -445,6 +445,55 @@ int ima_file_check(struct file *file, int mask) } EXPORT_SYMBOL_GPL(ima_file_check); +/** + * ima_file_hash - return the stored measurement if a file has been hashed and + * is in the iint cache. + * @file: pointer to the file + * @buf: buffer in which to store the hash + * @buf_size: length of the buffer + * + * On success, return the hash algorithm (as defined in the enum hash_algo). + * If buf is not NULL, this function also outputs the hash into buf. + * If the hash is larger than buf_size, then only buf_size bytes will be copied. + * It generally just makes sense to pass a buffer capable of holding the largest + * possible hash: IMA_MAX_DIGEST_SIZE. + * The file hash returned is based on the entire file, including the appended + * signature. + * + * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. + * If the parameters are incorrect, return -EINVAL. + */ +int ima_file_hash(struct file *file, char *buf, size_t buf_size) +{ + struct inode *inode; + struct integrity_iint_cache *iint; + int hash_algo; + + if (!file) + return -EINVAL; + + if (!ima_policy_flag) + return -EOPNOTSUPP; + + inode = file_inode(file); + iint = integrity_iint_find(inode); + if (!iint) + return -EOPNOTSUPP; + + mutex_lock(&iint->mutex); + if (buf) { + size_t copied_size; + + copied_size = min_t(size_t, iint->ima_hash->length, buf_size); + memcpy(buf, iint->ima_hash->digest, copied_size); + } + hash_algo = iint->ima_hash->algo; + mutex_unlock(&iint->mutex); + + return hash_algo; +} +EXPORT_SYMBOL_GPL(ima_file_hash); + /** * ima_post_create_tmpfile - mark newly created tmpfile as new * @file : newly created tmpfile -- cgit v1.2.3