From: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> Subject: ima: maintain memory size needed for serializing the measurement list In preparation for serializing the binary_runtime_measurements, this patch maintains the amount of memory required. Link: http://lkml.kernel.org/r/1480554346-29071-5-git-send-email-zohar@xxxxxxxxxxxxxxxxxx Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> Acked-by: Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx> Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Andreas Steffen <andreas.steffen@xxxxxxxxxxxxxx> Cc: Josh Sklar <sklar@xxxxxxxxxxxxxxxxxx> Cc: Dave Young <dyoung@xxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Stewart Smith <stewart@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- security/integrity/ima/Kconfig | 12 ++++++ security/integrity/ima/ima.h | 1 security/integrity/ima/ima_queue.c | 53 +++++++++++++++++++++++++-- 3 files changed, 64 insertions(+), 2 deletions(-) diff -puN security/integrity/ima/Kconfig~ima-maintain-memory-size-needed-for-serializing-the-measurement-list security/integrity/ima/Kconfig --- a/security/integrity/ima/Kconfig~ima-maintain-memory-size-needed-for-serializing-the-measurement-list +++ a/security/integrity/ima/Kconfig @@ -27,6 +27,18 @@ config IMA to learn more about IMA. If unsure, say N. +config IMA_KEXEC + bool "Enable carrying the IMA measurement list across a soft boot" + depends on IMA && TCG_TPM && HAVE_IMA_KEXEC + default n + help + TPM PCRs are only reset on a hard reboot. In order to validate + a TPM's quote after a soft boot, the IMA measurement list of the + running kernel must be saved and restored on boot. + + Depending on the IMA policy, the measurement list can grow to + be very large. + config IMA_MEASURE_PCR_IDX int depends on IMA diff -puN security/integrity/ima/ima.h~ima-maintain-memory-size-needed-for-serializing-the-measurement-list security/integrity/ima/ima.h --- a/security/integrity/ima/ima.h~ima-maintain-memory-size-needed-for-serializing-the-measurement-list +++ a/security/integrity/ima/ima.h @@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m struct ima_template_desc *ima_template_desc_current(void); int ima_restore_measurement_entry(struct ima_template_entry *entry); int ima_restore_measurement_list(loff_t bufsize, void *buf); +unsigned long ima_get_binary_runtime_size(void); int ima_init_template(void); /* diff -puN security/integrity/ima/ima_queue.c~ima-maintain-memory-size-needed-for-serializing-the-measurement-list security/integrity/ima/ima_queue.c --- a/security/integrity/ima/ima_queue.c~ima-maintain-memory-size-needed-for-serializing-the-measurement-list +++ a/security/integrity/ima/ima_queue.c @@ -29,6 +29,11 @@ #define AUDIT_CAUSE_LEN_MAX 32 LIST_HEAD(ima_measurements); /* list of all measurements */ +#ifdef CONFIG_IMA_KEXEC +static unsigned long binary_runtime_size; +#else +static unsigned long binary_runtime_size = ULONG_MAX; +#endif /* key: inode (before secure-hashing a file) */ struct ima_h_table ima_htable = { @@ -64,6 +69,24 @@ static struct ima_queue_entry *ima_looku return ret; } +/* + * Calculate the memory required for serializing a single + * binary_runtime_measurement list entry, which contains a + * couple of variable length fields (e.g template name and data). + */ +static int get_binary_runtime_size(struct ima_template_entry *entry) +{ + int size = 0; + + size += sizeof(u32); /* pcr */ + size += sizeof(entry->digest); + size += sizeof(int); /* template name size field */ + size += strlen(entry->template_desc->name) + 1; + size += sizeof(entry->template_data_len); + size += entry->template_data_len; + return size; +} + /* ima_add_template_entry helper function: * - Add template entry to the measurement list and hash table, for * all entries except those carried across kexec. @@ -91,9 +114,30 @@ static int ima_add_digest_entry(struct i key = ima_hash_key(entry->digest); hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]); } + + if (binary_runtime_size != ULONG_MAX) { + int size; + + size = get_binary_runtime_size(entry); + binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ? + binary_runtime_size + size : ULONG_MAX; + } return 0; } +/* + * Return the amount of memory required for serializing the + * entire binary_runtime_measurement list, including the ima_kexec_hdr + * structure. + */ +unsigned long ima_get_binary_runtime_size(void) +{ + if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr))) + return ULONG_MAX; + else + return binary_runtime_size + sizeof(struct ima_kexec_hdr); +}; + static int ima_pcr_extend(const u8 *hash, int pcr) { int result = 0; @@ -107,8 +151,13 @@ static int ima_pcr_extend(const u8 *hash return result; } -/* Add template entry to the measurement list and hash table, - * and extend the pcr. +/* + * Add template entry to the measurement list and hash table, and + * extend the pcr. + * + * On systems which support carrying the IMA measurement list across + * kexec, maintain the total memory size required for serializing the + * binary_runtime_measurements. */ int ima_add_template_entry(struct ima_template_entry *entry, int violation, const char *op, struct inode *inode, _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
