| Message ID | 20190617183507.14160-3-prsriva02@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for measuring the boot command line during kexec_file_load | expand |
On Mon, 2019-06-17 at 11:35 -0700, Prakhar Srivastava wrote: > A buffer(kexec boot command line arguments) measured into IMA > measuremnt list cannot be appraised, without already being > aware of the buffer contents. Since hashes are non-reversible, > raw buffer is needed for validation or regenerating hash for > appraisal/attestation. > > Add support to store/read the buffer contents in HEX. > The kexec cmdline hash is stored in the "d-ng" field of the > template data,it can be verified using > sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements | > grep kexec-cmdline | cut -d' ' -f 6 | xxd -r -p | sha256sum > > - Add two new fields to ima_event_data to hold the buf and > buf_len [Suggested by Roberto] > - Add a new temaplte field 'buf' to be used to store/read > the buffer data.[Suggested by Mimi] > - Updated process_buffer_meaurement to add the buffer to > ima_event_data. process_buffer_measurement added in > "Define a new IMA hook to measure the boot command line > arguments" > - Add a new template policy name ima-buf to represent > 'd-ng|n-ng|buf' > > Signed-off-by: Prakhar Srivastava <prsriva02@gmail.com> > Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com> > Reviewed-by: James Morris <jamorris@linux.microsoft.com> Thanks, looking much better. > > /* IMA template field data definition */ > diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c > index ea7d8cbf712f..83ca99d65e4b 100644 > --- a/security/integrity/ima/ima_api.c > +++ b/security/integrity/ima/ima_api.c > @@ -140,7 +140,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, > struct ima_template_entry *entry; > struct inode *inode = file_inode(file); > struct ima_event_data event_data = {iint, file, filename, NULL, 0, > - cause}; > + cause, NULL, 0}; > int violation = 1; > int result; > > @@ -296,7 +296,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, > struct inode *inode = file_inode(file); > struct ima_template_entry *entry; > struct ima_event_data event_data = {iint, file, filename, xattr_value, > - xattr_len, NULL}; > + xattr_len, NULL, NULL, 0}; > int violation = 0; > > if (iint->measured_pcrs & (0x1 << pcr)) > diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c > index 993d0f1915ff..c8591406c0e2 100644 > --- a/security/integrity/ima/ima_init.c > +++ b/security/integrity/ima/ima_init.c > @@ -50,7 +50,7 @@ static int __init ima_add_boot_aggregate(void) > struct ima_template_entry *entry; > struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; > struct ima_event_data event_data = {iint, NULL, boot_aggregate_name, > - NULL, 0, NULL}; > + NULL, 0, NULL, NULL, 0}; > int result = -ENOMEM; > int violation = 0; > struct { > These changes shouldn't be necessary. Please rebase these patches on top of the latest next-queued-testing branch (git remote update). "IMA: support for per policy rule template formats" is still changing. Minor nit. When re-posting the patches please update the patch titles so that there is a space between the subsystem name and the patch title (eg. "ima: define ..."). Mimi
<snip> > > if (iint->measured_pcrs & (0x1 << pcr)) > > diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c > > index 993d0f1915ff..c8591406c0e2 100644 > > --- a/security/integrity/ima/ima_init.c > > +++ b/security/integrity/ima/ima_init.c > > @@ -50,7 +50,7 @@ static int __init ima_add_boot_aggregate(void) > > struct ima_template_entry *entry; > > struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; > > struct ima_event_data event_data = {iint, NULL, boot_aggregate_name, > > - NULL, 0, NULL}; > > + NULL, 0, NULL, NULL, 0}; > > int result = -ENOMEM; > > int violation = 0; > > struct { > > > > These changes shouldn't be necessary. Please rebase these patches on > top of the latest next-queued-testing branch (git remote update). "IMA: support for per > policy rule template formats" is still changing. > > Minor nit. When re-posting the patches please update the patch titles > so that there is a space between the subsystem name and the patch > title (eg. "ima: define ..."). > I believe the above event_data changes are needed, to store/read the buffer length and buffer itself. The only exception will be if needed will be to remove ima-buf as a template instead used a template_fmt in the policy with KEXEC_CMDLINE from the "IMA: support for per policy rule template formats" is still changing.". In my view even ima-buf is needed as it simplifies the usage. Please let me know if I misunderstood your comment. > Mimi >
On Wed, 2019-06-19 at 11:08 -0700, prakhar srivastava wrote: > <snip> > > > if (iint->measured_pcrs & (0x1 << pcr)) > > > diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c > > > index 993d0f1915ff..c8591406c0e2 100644 > > > --- a/security/integrity/ima/ima_init.c > > > +++ b/security/integrity/ima/ima_init.c > > > @@ -50,7 +50,7 @@ static int __init ima_add_boot_aggregate(void) > > > struct ima_template_entry *entry; > > > struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; > > > struct ima_event_data event_data = {iint, NULL, boot_aggregate_name, > > > - NULL, 0, NULL}; > > > + NULL, 0, NULL, NULL, 0}; > > > int result = -ENOMEM; > > > int violation = 0; > > > struct { > > > > > > > These changes shouldn't be necessary. Please rebase these patches on > > top of the latest next-queued-testing branch (git remote update). "IMA: support for per > > policy rule template formats" is still changing. > > > > Minor nit. When re-posting the patches please update the patch titles > > so that there is a space between the subsystem name and the patch > > title (eg. "ima: define ..."). > > > I believe the above event_data changes are needed, to store/read the > buffer length and buffer itself. The only exception will be if needed will be to > remove ima-buf as a template instead used a template_fmt in the policy > with KEXEC_CMDLINE from the "IMA: support for per > policy rule template formats" is still changing.". > In my view even ima-buf is needed as it simplifies the usage. > > Please let me know if I misunderstood your comment. The tip of next-queued-testing branch is commit 687d57f90461 ("IMA: support for per policy rule template formats"). The current code is: struct ima_event_data event_data = { .iint = iint, .filename = boot_aggregate_name }; Mimi
diff --git a/Documentation/security/IMA-templates.rst b/Documentation/security/IMA-templates.rst index 2cd0e273cc9a..fccdbbc984f5 100644 --- a/Documentation/security/IMA-templates.rst +++ b/Documentation/security/IMA-templates.rst @@ -69,14 +69,15 @@ descriptors by adding their identifier to the format string algorithm (field format: [<hash algo>:]digest, where the digest prefix is shown only if the hash algorithm is not SHA1 or MD5); - 'n-ng': the name of the event, without size limitations; - - 'sig': the file signature. - + - 'sig': the file signature; + - 'buf': the buffer data that was used to generate the hash without size limitations; Below, there is the list of defined template descriptors: - "ima": its format is ``d|n``; - "ima-ng" (default): its format is ``d-ng|n-ng``; - - "ima-sig": its format is ``d-ng|n-ng|sig``. + - "ima-sig": its format is ``d-ng|n-ng|sig``; + - "ima-buf": its format is ``d-ng|n-ng|buf``; diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index a4ad1270bffa..16110180545c 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -65,6 +65,8 @@ struct ima_event_data { struct evm_ima_xattr_data *xattr_value; int xattr_len; const char *violation; + const void *buf; + int buf_len; }; /* IMA template field data definition */ diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index ea7d8cbf712f..83ca99d65e4b 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -140,7 +140,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, struct ima_template_entry *entry; struct inode *inode = file_inode(file); struct ima_event_data event_data = {iint, file, filename, NULL, 0, - cause}; + cause, NULL, 0}; int violation = 1; int result; @@ -296,7 +296,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct inode *inode = file_inode(file); struct ima_template_entry *entry; struct ima_event_data event_data = {iint, file, filename, xattr_value, - xattr_len, NULL}; + xattr_len, NULL, NULL, 0}; int violation = 0; if (iint->measured_pcrs & (0x1 << pcr)) diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 993d0f1915ff..c8591406c0e2 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -50,7 +50,7 @@ static int __init ima_add_boot_aggregate(void) struct ima_template_entry *entry; struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; struct ima_event_data event_data = {iint, NULL, boot_aggregate_name, - NULL, 0, NULL}; + NULL, 0, NULL, NULL, 0}; int result = -ENOMEM; int violation = 0; struct { diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 1e233417a7af..84b321ac1ad3 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -638,6 +638,8 @@ static void process_buffer_measurement(const void *buf, int size, goto out; event_data.filename = eventname; + event_data.buf = buf; + event_data.buf_len = size; iint.ima_hash = &hash.hdr; iint.ima_hash->algo = ima_hash_algo; diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index e6e892f31cbd..632f314c0e5a 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -26,6 +26,7 @@ static struct ima_template_desc builtin_templates[] = { {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT}, {.name = "ima-ng", .fmt = "d-ng|n-ng"}, {.name = "ima-sig", .fmt = "d-ng|n-ng|sig"}, + {.name = "ima-buf", .fmt = "d-ng|n-ng|buf"}, {.name = "", .fmt = ""}, /* placeholder for a custom format */ }; @@ -43,6 +44,8 @@ static const struct ima_template_field supported_fields[] = { .field_show = ima_show_template_string}, {.field_id = "sig", .field_init = ima_eventsig_init, .field_show = ima_show_template_sig}, + {.field_id = "buf", .field_init = ima_eventbuf_init, + .field_show = ima_show_template_buf}, }; #define MAX_TEMPLATE_NAME_LEN 15 diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c index 513b457ae900..baf4de45c5aa 100644 --- a/security/integrity/ima/ima_template_lib.c +++ b/security/integrity/ima/ima_template_lib.c @@ -162,6 +162,12 @@ void ima_show_template_sig(struct seq_file *m, enum ima_show_type show, ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data); } +void ima_show_template_buf(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data) +{ + ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data); +} + /** * ima_parse_buf() - Parses lengths and data from an input buffer * @bufstartp: Buffer start address. @@ -389,3 +395,18 @@ int ima_eventsig_init(struct ima_event_data *event_data, return ima_write_template_field_data(xattr_value, event_data->xattr_len, DATA_FMT_HEX, field_data); } + +/* + * ima_eventbuf_init - include the buffer(kexec-cmldine) as part of the + * template data. + */ +int ima_eventbuf_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + if ((!event_data->buf) || (event_data->buf_len == 0)) + return 0; + + return ima_write_template_field_data(event_data->buf, + event_data->buf_len, DATA_FMT_HEX, + field_data); +} diff --git a/security/integrity/ima/ima_template_lib.h b/security/integrity/ima/ima_template_lib.h index 6a3d8b831deb..12f1a8578b31 100644 --- a/security/integrity/ima/ima_template_lib.h +++ b/security/integrity/ima/ima_template_lib.h @@ -29,6 +29,8 @@ void ima_show_template_string(struct seq_file *m, enum ima_show_type show, struct ima_field_data *field_data); void ima_show_template_sig(struct seq_file *m, enum ima_show_type show, struct ima_field_data *field_data); +void ima_show_template_buf(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data); int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp, int maxfields, struct ima_field_data *fields, int *curfields, unsigned long *len_mask, int enforce_mask, char *bufname); @@ -42,4 +44,6 @@ int ima_eventname_ng_init(struct ima_event_data *event_data, struct ima_field_data *field_data); int ima_eventsig_init(struct ima_event_data *event_data, struct ima_field_data *field_data); +int ima_eventbuf_init(struct ima_event_data *event_data, + struct ima_field_data *field_data); #endif /* __LINUX_IMA_TEMPLATE_LIB_H */