This is preparatory patch to use tsm measurement registers in IMA. Introduce tsm_default_tm() and tsm_mr_read()/write() APIs to read and extend the tsm measurement registers in IMA.
Since IMA is supported only when it's built as built-in, export those symbols only tsm-mr is built as built-in. Signed-off-by: Yeoreum Yun <[email protected]> --- drivers/virt/coco/guest/tsm-mr.c | 159 +++++++++++++++++++++++++++++++++------ include/linux/tsm-mr.h | 26 +++++++ 2 files changed, 161 insertions(+), 24 deletions(-) diff --git a/drivers/virt/coco/guest/tsm-mr.c b/drivers/virt/coco/guest/tsm-mr.c index 657b9c5739d0..9e721348be8d 100644 --- a/drivers/virt/coco/guest/tsm-mr.c +++ b/drivers/virt/coco/guest/tsm-mr.c @@ -7,9 +7,15 @@ #include <linux/slab.h> #include <linux/sysfs.h> + #define CREATE_TRACE_POINTS #include <trace/events/tsm_mr.h> +#define TM_NUM_CTX (64 * HASH_ALGO__LAST) + +DEFINE_IDR(tm_ctx_idr); +static DEFINE_MUTEX(idr_lock); + /* * struct tm_context - contains everything necessary to implement sysfs * attributes for MRs. @@ -42,21 +48,16 @@ struct tm_context { struct bin_attribute mrs[]; }; -static ssize_t tm_digest_read(struct file *filp, struct kobject *kobj, - const struct bin_attribute *attr, char *buffer, - loff_t off, size_t count) +static ssize_t __tsm_mr_read(struct tm_context *ctx, + const struct tsm_measurement_register *mr, + char *buffer, loff_t off, size_t count) { - struct tm_context *ctx; - const struct tsm_measurement_register *mr; int rc; - ctx = attr->private; rc = down_read_interruptible(&ctx->rwsem); if (rc) return rc; - mr = &ctx->tm->mrs[attr - ctx->mrs]; - /* * @ctx->in_sync indicates if the MR cache is stale. It is a global * instead of a per-MR flag for simplicity, as most (if not all) archs @@ -88,20 +89,11 @@ static ssize_t tm_digest_read(struct file *filp, struct kobject *kobj, return rc ?: count; } -static ssize_t tm_digest_write(struct file *filp, struct kobject *kobj, - const struct bin_attribute *attr, char *buffer, - loff_t off, size_t count) +static ssize_t __tsm_mr_write(struct tm_context *ctx, + const struct tsm_measurement_register *mr, + char *buffer, size_t count) { - struct tm_context *ctx; - const struct tsm_measurement_register *mr; - ssize_t rc; - - /* partial writes are not supported */ - if (off != 0 || count != attr->size) - return -EINVAL; - - ctx = attr->private; - mr = &ctx->tm->mrs[attr - ctx->mrs]; + int rc; rc = down_write_killable(&ctx->rwsem); if (rc) @@ -119,6 +111,36 @@ static ssize_t tm_digest_write(struct file *filp, struct kobject *kobj, return rc ?: count; } +static ssize_t tm_digest_read(struct file *filp, struct kobject *kobj, + const struct bin_attribute *attr, char *buffer, + loff_t off, size_t count) +{ + struct tm_context *ctx; + const struct tsm_measurement_register *mr; + + ctx = attr->private; + mr = &ctx->tm->mrs[attr - ctx->mrs]; + + return __tsm_mr_read(ctx, mr, buffer, off, count); +} + +static ssize_t tm_digest_write(struct file *filp, struct kobject *kobj, + const struct bin_attribute *attr, char *buffer, + loff_t off, size_t count) +{ + struct tm_context *ctx; + const struct tsm_measurement_register *mr; + + /* partial writes are not supported */ + if (off != 0 || count != attr->size) + return -EINVAL; + + ctx = attr->private; + mr = &ctx->tm->mrs[attr - ctx->mrs]; + + return __tsm_mr_write(ctx, mr, buffer, count); +} + /** * tsm_mr_create_attribute_group() - creates an attribute group for measurement * registers (MRs) @@ -138,8 +160,7 @@ static ssize_t tm_digest_write(struct file *filp, struct kobject *kobj, * * %-ENOMEM - Out of memory. */ const struct attribute_group * -tsm_mr_create_attribute_group(const struct tsm_measurements *tm) -{ +tsm_mr_create_attribute_group(const struct tsm_measurements *tm) { size_t nlen; if (!tm || !tm->mrs) @@ -230,6 +251,15 @@ tsm_mr_create_attribute_group(const struct tsm_measurements *tm) ctx->agrp.name = "measurements"; ctx->agrp.bin_attrs = no_free_ptr(attrs); ctx->tm = tm; + + guard(mutex)(&idr_lock); + ((struct tsm_measurements *)tm)->ctx_id = idr_alloc(&tm_ctx_idr, ctx, 0, + TM_NUM_CTX, GFP_KERNEL); + if (tm->ctx_id < 0) { + kfree(ctx->agrp.bin_attrs); + return ERR_PTR(tm->ctx_id); + } + return &no_free_ptr(ctx)->agrp; } EXPORT_SYMBOL_GPL(tsm_mr_create_attribute_group); @@ -243,9 +273,90 @@ EXPORT_SYMBOL_GPL(tsm_mr_create_attribute_group); */ void tsm_mr_free_attribute_group(const struct attribute_group *attr_grp) { + struct tm_context *ctx; + if (!IS_ERR_OR_NULL(attr_grp)) { + ctx = container_of(attr_grp, struct tm_context, agrp); + scoped_guard(mutex, &idr_lock) + idr_remove(&tm_ctx_idr, ctx->tm->ctx_id); kfree(attr_grp->bin_attrs); - kfree(container_of(attr_grp, struct tm_context, agrp)); + kfree(ctx); } } EXPORT_SYMBOL_GPL(tsm_mr_free_attribute_group); + +#if defined(CONFIG_TSM_MEASUREMENTS) +const struct tsm_measurements *tsm_default_tm(void) +{ + struct tm_context *ctx; + int next_id = 0; + + guard(mutex)(&idr_lock); + + ctx = idr_get_next(&tm_ctx_idr, &next_id); + if (!ctx) + return NULL; + + return ctx->tm; +} +EXPORT_SYMBOL_GPL(tsm_default_tm); + +int tsm_mr_read(const struct tsm_measurements *tm, int idx, + u8 *digest, u32 digest_size) +{ + struct tm_context *ctx; + const struct tsm_measurement_register *mr; + int rc; + + scoped_guard(mutex, &idr_lock) + ctx = idr_find(&tm_ctx_idr, tm->ctx_id); + + if (IS_ERR_OR_NULL(ctx)) + return -ENODEV; + + if (!digest || (idx >= ctx->tm->nr_mrs) || + (ctx->tm->mrs[idx].mr_size > digest_size) || + !(ctx->tm->mrs[idx].mr_flags & TSM_MR_F_READABLE)) + return -EINVAL; + + mr = &ctx->tm->mrs[idx]; + + rc = __tsm_mr_read(ctx, mr, (char *)digest, 0, mr->mr_size); + if (rc < 0) + return rc; + + return 0; +} +EXPORT_SYMBOL_GPL(tsm_mr_read); + +int tsm_mr_write(const struct tsm_measurements *tm, int idx, + u8 *digest, u32 digest_size) +{ + struct tm_context *ctx; + const struct tsm_measurement_register *mr; + int rc; + + scoped_guard(mutex, &idr_lock) + ctx = idr_find(&tm_ctx_idr, tm->ctx_id); + + if (IS_ERR_OR_NULL(ctx)) + return -ENODEV; + + if (!digest || (idx >= ctx->tm->nr_mrs) || + !(ctx->tm->mrs[idx].mr_flags & TSM_MR_F_WRITABLE)) + return -EINVAL; + + /* partial writes are not supported */ + if (ctx->tm->mrs[idx].mr_size != digest_size) + return -EINVAL; + + mr = &ctx->tm->mrs[idx]; + + rc = __tsm_mr_write(ctx, mr, (char *)digest, mr->mr_size); + if (rc < 0) + return rc; + + return 0; +} +EXPORT_SYMBOL_GPL(tsm_mr_write); +#endif diff --git a/include/linux/tsm-mr.h b/include/linux/tsm-mr.h index 50a521f4ac97..43a0f761cd96 100644 --- a/include/linux/tsm-mr.h +++ b/include/linux/tsm-mr.h @@ -80,10 +80,36 @@ struct tsm_measurements { int (*refresh)(const struct tsm_measurements *tm); int (*write)(const struct tsm_measurements *tm, const struct tsm_measurement_register *mr, const u8 *data); + int ctx_id; }; const struct attribute_group * tsm_mr_create_attribute_group(const struct tsm_measurements *tm); void tsm_mr_free_attribute_group(const struct attribute_group *attr_grp); +#if defined(CONFIG_TSM_MEASUREMENTS) +const struct tsm_measurements *tsm_default_tm(void); +int tsm_mr_read(const struct tsm_measurements *tm, int idx, + u8 *digest, u32 digest_size); +int tsm_mr_write(const struct tsm_measurements *tm, int idx, + u8 *digest, u32 digest_size); +#else +static inline const struct tsm_measurements *tsm_default_tm(void) +{ + return NULL; +} + +static inline int tsm_mr_read(const struct tsm_measurements *tm, int idx, + u8 *digest, u32 digest_size) +{ + return 0; +} + +static inline int tsm_mr_write(const struct tsm_measurements *tm, int idx, + u8 *digest, u32 digest_size) +{ + return 0; +} +#endif + #endif -- 2.43.0
