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SubjectRe: [PATCH v2 2/5 RFC] use event name instead of enum to make the call generic
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On 2019-04-25 4:48 a.m., Nayna wrote:
>
>
> On 04/23/2019 08:15 PM, Prakhar Srivastava wrote:
>> From: Prakhar Srivastava <prsriva02@gmail.com>
>>
>> Signed-off-by: Prakhar Srivastava <prsriva@microsoft.com>
>> ---
>>
>> Currently for soft reboot(kexec_file_load) the kernel file and
>> signature is measured by IMA. The cmdline args used to load the kernel
>> is not measured.
>> The boot aggregate that gets calculated will have no change since the
>> EFI loader has not been triggered.
>> Adding the kexec cmdline args measure and kernel version will add some
>> attestable criteria.
>>
>
> Any reason for including the whole commit message after "---"
>
> Anything after "---" is not included in the patch description when patch
> is applied.
>
> This comment applies to all the patches in this patchset.
I will fix the comments and send out the patchset with a cover letter.
Thankyou for pointing this out.
>
>> remove enums to control type of buffers entries, instead pass the
>> event name to be used.
>
> Is the last statement meant to be a Changelog from v1-> v2 ? Only the
> changelog has to be after "---"
>
> Also, If posting more than one patch, it is preferrable to add a
> cover-letter.
I will add a cover letter alongside fixing the comments. Thankyou!
>
>
>>   include/linux/ima.h               | 10 ++--------
>>   kernel/kexec_file.c               |  3 +++
>>   security/integrity/ima/ima.h      |  2 +-
>>   security/integrity/ima/ima_main.c | 30 ++++++++++--------------------
>>   4 files changed, 16 insertions(+), 29 deletions(-)
>>
>> diff --git a/include/linux/ima.h b/include/linux/ima.h
>> index 733d0cb9dedc..5e41507c57e5 100644
>> --- a/include/linux/ima.h
>> +++ b/include/linux/ima.h
>> @@ -14,12 +14,6 @@
>>   #include <linux/kexec.h>
>>   struct linux_binprm;
>>
>> -enum __buffer_id {
>> -    KERNEL_VERSION,
>> -    KEXEC_CMDLINE,
>> -    MAX_BUFFER_ID = KEXEC_CMDLINE
>> -} buffer_id;
>> -
>
> Is the v2 version created on top of the v1 version that was posted ?
>
v2 is based off the HEAD of the repo.
> The v2 version has to be on top of the HEAD of the repository itself,
> and not on the v1 version. Only the final reviewed and tested version
> makes to the upstream.
>
> Btw, which repository and its branch are you using ?
>
I am basing my changes off IMA branch:
git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
> Thanks & Regards,
>       - Nayna
>
>
>
>
>>   #ifdef CONFIG_IMA
>>   extern int ima_bprm_check(struct linux_binprm *bprm);
>>   extern int ima_file_check(struct file *file, int mask, int opened);
>> @@ -29,7 +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 void ima_buffer_check(const void *buff, int size, enum
>> buffer_id id);
>> +extern void ima_buffer_check(const void *buff, int size, char
>> *eventname);
>>   #ifdef CONFIG_IMA_KEXEC
>>   extern void ima_add_kexec_buffer(struct kimage *image);
>>   #endif
>> @@ -72,7 +66,7 @@ static inline void ima_post_path_mknod(struct dentry
>> *dentry)
>>   }
>>
>>   static inline void ima_buffer_check(const void *buff, int size,
>> -            enum buffer_id id)
>> +            char *eventname)
>>   {
>>       return;
>>   }
>> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
>> index b118735fea9d..2a5234eb4b28 100644
>> --- a/kernel/kexec_file.c
>> +++ b/kernel/kexec_file.c
>> @@ -182,6 +182,9 @@ kimage_file_prepare_segments(struct kimage *image,
>> int kernel_fd, int initrd_fd,
>>               ret = -EINVAL;
>>               goto out;
>>           }
>> +
>> +        ima_buffer_check(image->cmdline_buf, cmdline_len - 1,
>> +                "kexec_cmdline");
>>       }
>>
>>       /* Call arch image load handlers */
>> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
>> index b71f2f6f7421..fcade3c103ed 100644
>> --- a/security/integrity/ima/ima.h
>> +++ b/security/integrity/ima/ima.h
>> @@ -181,8 +181,8 @@ enum ima_hooks {
>>       FIRMWARE_CHECK,
>>       KEXEC_KERNEL_CHECK,
>>       KEXEC_INITRAMFS_CHECK,
>> -    BUFFER_CHECK,
>>       POLICY_CHECK,
>> +    BUFFER_CHECK,
>>       MAX_CHECK
>>   };
>>
>> diff --git a/security/integrity/ima/ima_main.c
>> b/security/integrity/ima/ima_main.c
>> index 6408cadaadbb..da82c705a5ed 100644
>> --- a/security/integrity/ima/ima_main.c
>> +++ b/security/integrity/ima/ima_main.c
>> @@ -160,8 +160,7 @@ void ima_file_free(struct file *file)
>>    * (Instead of using the file hash the buffer hash is used).
>>    * @buff - The buffer that needs to be added to the log
>>    * @size - size of buffer(in bytes)
>> - * @id - buffer id, this is differentiator for the various buffers
>> - * that can be measured.
>> + * @id - eventname, event name to be used for buffer measurement.
>>    *
>>    * The buffer passed is added to the ima logs.
>>    * If the sig template is used, then the sig field contains the buffer.
>> @@ -170,7 +169,7 @@ void ima_file_free(struct file *file)
>>    * On error cases surface errors from ima calls.
>>    */
>>   static int process_buffer_measurement(const void *buff, int size,
>> -                enum buffer_id id)
>> +                char *eventname)
>>   {
>>       int ret = -EINVAL;
>>       struct ima_template_entry *entry = NULL;
>> @@ -185,23 +184,13 @@ static int process_buffer_measurement(const void
>> *buff, int size,
>>       int violation = 0;
>>       int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
>>
>> -    if (!buff || size ==  0)
>> +    if (!buff || size ==  0 || !eventname)
>>           goto err_out;
>>
>>       if (ima_get_action(NULL, 0, BUFFER_CHECK, &pcr) != IMA_MEASURE)
>>           goto err_out;
>>
>> -    switch (buffer_id) {
>> -    case KERNEL_VERSION:
>> -        name = "Kernel-version";
>> -        break;
>> -    case KEXEC_CMDLINE:
>> -        name = "Kexec-cmdline";
>> -        break;
>> -    default:
>> -        goto err_out;
>> -    }
>> -
>> +    name = eventname;
>>       memset(iint, 0, sizeof(*iint));
>>       memset(&hash, 0, sizeof(hash));
>>
>> @@ -452,15 +441,16 @@ int ima_read_file(struct file *file, enum
>> kernel_read_file_id read_id)
>>    * ima_buffer_check - based on policy, collect & store buffer
>> measurement
>>    * @buf: pointer to buffer
>>    * @size: size of buffer
>> - * @buffer_id: caller identifier
>> + * @eventname: caller identifier
>>    *
>>    * Buffers can only be measured, not appraised.  The buffer identifier
>> - * is used as the measurement list entry name (eg. boot_cmdline).
>> + * is used as the measurement list entry name (eg. boot_cmdline,
>> + * kernel_version).
>>    */
>> -void ima_buffer_check(const void *buf, int size, enum buffer_id id)
>> +void ima_buffer_check(const void *buf, int size, char *eventname)
>>   {
>> -    if (buf && size != 0)
>> -        process_buffer_measurement(buf, size, id);
>> +    if (buf && size != 0 && eventname)
>> +        process_buffer_measurement(buf, size, eventname);
>>
>>       return;
>>   }

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