Re: [Linux-ima-devel] [PATCH v6 04/10] ima: maintain memory size needed for serializing the measurement list

[Mimi Zohar]

On Tue, 2016-11-08 at 22:05 +0200, Dmitry Kasatkin wrote:
> On Fri, Oct 21, 2016 at 5:44 AM, Thiago Jung Bauermann
>  wrote:
> > From: Mimi Zohar 
> >
> > In preparation for serializing the binary_runtime_measurements, this patch
> > maintains the amount of memory required.
> >
> > Changelog v5:
> > - replace CONFIG_KEXEC_FILE with architecture CONFIG_HAVE_IMA_KEXEC (Thiago)
> >
> > Changelog v3:
> > - include the ima_kexec_hdr size in the binary_runtime_measurement size.
> >
> > Signed-off-by: Mimi Zohar 
> > ---
> >  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 --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> > index 5487827fa86c..370eb2f4dd37 100644
> > --- a/security/integrity/ima/Kconfig
> > +++ b/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 --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> > index 51dc8d57d64d..ea1dcc452911 100644
> > --- a/security/integrity/ima/ima.h
> > +++ b/security/integrity/ima/ima.h
> > @@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m, u8 *digest, 
> > u32 size);
> >  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 --git a/security/integrity/ima/ima_queue.c 
> > b/security/integrity/ima/ima_queue.c
> > index 12d1b040bca9..3a3cc2a45645 100644
> > --- a/security/integrity/ima/ima_queue.c
> > +++ b/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_lookup_digest_entry(u8 *digest_value,
> > 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);
> > +   size += sizeof(entry->template_data_len);
> > +   size += entry->template_data_len;
> > +   return size;
> > +}
> > +
> 
> strlen returns len without '\0'. I cannot see how you would know how
> to read it back?

This function is used to keep a running memory size needed for
allocating the buffer to carry the measurement list across kexec.

Right, the memory need for the template name is +1.

Mimi

> 
> >  /* ima_add_template_entry helper function:
> >   * - Add template entry to the measurement list and hash table, for
> >   *   all entries except those carried across kexec.
> > @@ -90,9 +113,30 @@ static int ima_add_digest_entry(struct 
> > ima_template_entry *entry, int flags)
> > key = ima_hash_key(entry->digest);
> > hlist_add_head_rcu(>hnext, _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 

Re: [Linux-ima-devel] [PATCH v6 04/10] ima: maintain memory size needed for serializing the measurement list

[Mimi Zohar]

On Tue, 2016-11-08 at 22:05 +0200, Dmitry Kasatkin wrote:
> On Fri, Oct 21, 2016 at 5:44 AM, Thiago Jung Bauermann
>  wrote:
> > From: Mimi Zohar 
> >
> > In preparation for serializing the binary_runtime_measurements, this patch
> > maintains the amount of memory required.
> >
> > Changelog v5:
> > - replace CONFIG_KEXEC_FILE with architecture CONFIG_HAVE_IMA_KEXEC (Thiago)
> >
> > Changelog v3:
> > - include the ima_kexec_hdr size in the binary_runtime_measurement size.
> >
> > Signed-off-by: Mimi Zohar 
> > ---
> >  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 --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> > index 5487827fa86c..370eb2f4dd37 100644
> > --- a/security/integrity/ima/Kconfig
> > +++ b/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 --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> > index 51dc8d57d64d..ea1dcc452911 100644
> > --- a/security/integrity/ima/ima.h
> > +++ b/security/integrity/ima/ima.h
> > @@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m, u8 *digest, 
> > u32 size);
> >  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 --git a/security/integrity/ima/ima_queue.c 
> > b/security/integrity/ima/ima_queue.c
> > index 12d1b040bca9..3a3cc2a45645 100644
> > --- a/security/integrity/ima/ima_queue.c
> > +++ b/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_lookup_digest_entry(u8 *digest_value,
> > 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);
> > +   size += sizeof(entry->template_data_len);
> > +   size += entry->template_data_len;
> > +   return size;
> > +}
> > +
> 
> strlen returns len without '\0'. I cannot see how you would know how
> to read it back?

This function is used to keep a running memory size needed for
allocating the buffer to carry the measurement list across kexec.

Right, the memory need for the template name is +1.

Mimi

> 
> >  /* ima_add_template_entry helper function:
> >   * - Add template entry to the measurement list and hash table, for
> >   *   all entries except those carried across kexec.
> > @@ -90,9 +113,30 @@ static int ima_add_digest_entry(struct 
> > ima_template_entry *entry, int flags)
> > key = ima_hash_key(entry->digest);
> > hlist_add_head_rcu(>hnext, _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 

Re: [Linux-ima-devel] [PATCH v6 04/10] ima: maintain memory size needed for serializing the measurement list

[Dmitry Kasatkin]

On Fri, Oct 21, 2016 at 5:44 AM, Thiago Jung Bauermann
 wrote:
> From: Mimi Zohar 
>
> In preparation for serializing the binary_runtime_measurements, this patch
> maintains the amount of memory required.
>
> Changelog v5:
> - replace CONFIG_KEXEC_FILE with architecture CONFIG_HAVE_IMA_KEXEC (Thiago)
>
> Changelog v3:
> - include the ima_kexec_hdr size in the binary_runtime_measurement size.
>
> Signed-off-by: Mimi Zohar 
> ---
>  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 --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> index 5487827fa86c..370eb2f4dd37 100644
> --- a/security/integrity/ima/Kconfig
> +++ b/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 --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 51dc8d57d64d..ea1dcc452911 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m, u8 *digest, u32 
> size);
>  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 --git a/security/integrity/ima/ima_queue.c 
> b/security/integrity/ima/ima_queue.c
> index 12d1b040bca9..3a3cc2a45645 100644
> --- a/security/integrity/ima/ima_queue.c
> +++ b/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_lookup_digest_entry(u8 
> *digest_value,
> 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);
> +   size += sizeof(entry->template_data_len);
> +   size += entry->template_data_len;
> +   return size;
> +}
> +

strlen returns len without '\0'. I cannot see how you would know how
to read it back?


>  /* ima_add_template_entry helper function:
>   * - Add template entry to the measurement list and hash table, for
>   *   all entries except those carried across kexec.
> @@ -90,9 +113,30 @@ static int ima_add_digest_entry(struct ima_template_entry 
> *entry, int flags)
> key = ima_hash_key(entry->digest);
> hlist_add_head_rcu(>hnext, _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;
> @@ -106,8 +150,13 @@ static int ima_pcr_extend(const u8 *hash, int pcr)
> return 

Re: [Linux-ima-devel] [PATCH v6 04/10] ima: maintain memory size needed for serializing the measurement list

[Dmitry Kasatkin]

On Fri, Oct 21, 2016 at 5:44 AM, Thiago Jung Bauermann
 wrote:
> From: Mimi Zohar 
>
> In preparation for serializing the binary_runtime_measurements, this patch
> maintains the amount of memory required.
>
> Changelog v5:
> - replace CONFIG_KEXEC_FILE with architecture CONFIG_HAVE_IMA_KEXEC (Thiago)
>
> Changelog v3:
> - include the ima_kexec_hdr size in the binary_runtime_measurement size.
>
> Signed-off-by: Mimi Zohar 
> ---
>  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 --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> index 5487827fa86c..370eb2f4dd37 100644
> --- a/security/integrity/ima/Kconfig
> +++ b/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 --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 51dc8d57d64d..ea1dcc452911 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m, u8 *digest, u32 
> size);
>  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 --git a/security/integrity/ima/ima_queue.c 
> b/security/integrity/ima/ima_queue.c
> index 12d1b040bca9..3a3cc2a45645 100644
> --- a/security/integrity/ima/ima_queue.c
> +++ b/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_lookup_digest_entry(u8 
> *digest_value,
> 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);
> +   size += sizeof(entry->template_data_len);
> +   size += entry->template_data_len;
> +   return size;
> +}
> +

strlen returns len without '\0'. I cannot see how you would know how
to read it back?


>  /* ima_add_template_entry helper function:
>   * - Add template entry to the measurement list and hash table, for
>   *   all entries except those carried across kexec.
> @@ -90,9 +113,30 @@ static int ima_add_digest_entry(struct ima_template_entry 
> *entry, int flags)
> key = ima_hash_key(entry->digest);
> hlist_add_head_rcu(>hnext, _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;
> @@ -106,8 +150,13 @@ static int ima_pcr_extend(const u8 *hash, int pcr)
> return result;
>  }
>
> -/* Add template entry to the measurement list and hash table,
> -