| Message ID | 20250124225547.22684-7-chenste@linux.microsoft.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ima: kexec: measure events between kexec load and excute | expand |
On 1/24/25 5:55 PM, steven chen wrote: > The extra memory allocated for carrying the IMA measurement list across > kexec is hard-coded as half a PAGE. Make it configurable. > > Define a Kconfig option, IMA_KEXEC_EXTRA_MEMORY_KB, to configure the > extra memory (in kb) to be allocated for IMA measurements added during > kexec soft reboot. Ensure the default value of the option is set such > that extra half a page of memory for additional measurements is allocated > for the additional measurements. > > Update ima_add_kexec_buffer() function to allocate memory based on the > Kconfig option value, rather than the currently hard-coded one. > > From: Tushar Sugandhi <tusharsu@linux.microsoft.com> > Author: Tushar Sugandhi <tusharsu@linux.microsoft.com> > Suggested-by: Stefan Berger <stefanb@linux.ibm.com> > Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> > Signed-off-by: steven chen <chenste@linux.microsoft.com> > --- > security/integrity/ima/Kconfig | 10 ++++++++++ > security/integrity/ima/ima_kexec.c | 16 ++++++++++------ > 2 files changed, 20 insertions(+), 6 deletions(-) > > diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig > index 475c32615006..7dd2ed8b2cdc 100644 > --- a/security/integrity/ima/Kconfig > +++ b/security/integrity/ima/Kconfig > @@ -321,4 +321,14 @@ config IMA_DISABLE_HTABLE > help > This option disables htable to allow measurement of duplicate records. > > +config IMA_KEXEC_EXTRA_MEMORY_KB > + int int "Extra memory for IMA measurements added during kexec soft reboot" Without the description I wasn't able to modify the value. > + depends on IMA_KEXEC > + default 0 > + help > + IMA_KEXEC_EXTRA_MEMORY_KB determines the extra memory to be > + allocated (in kb) for IMA measurements added during kexec soft reboot. > + If set to the default value, an extra half a page of memory for those > + additional measurements will be allocated. > + > endif > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c > index d5f004cfeaec..c9c916f69ca7 100644 > --- a/security/integrity/ima/ima_kexec.c > +++ b/security/integrity/ima/ima_kexec.c > @@ -128,22 +128,26 @@ void ima_add_kexec_buffer(struct kimage *image) > .buf_min = 0, .buf_max = ULONG_MAX, > .top_down = true }; > unsigned long binary_runtime_size; > - > + unsigned long extra_size; > /* use more understandable variable names than defined in kbuf */ > void *kexec_buffer = NULL; > size_t kexec_buffer_size = 0; > int ret; > > /* > - * Reserve an extra half page of memory for additional measurements > - * added during the kexec load. > + * Reserve extra memory for measurements added during kexec. > */ > - binary_runtime_size = ima_get_binary_runtime_size(); > + if (CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB <= 0) > + extra_size = PAGE_SIZE / 2; > + else > + extra_size = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024; > + binary_runtime_size = ima_get_binary_runtime_size() + extra_size; > + > if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) > kexec_segment_size = ULONG_MAX; > else > - kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + > - PAGE_SIZE / 2, PAGE_SIZE); > + kexec_segment_size = ALIGN(binary_runtime_size, PAGE_SIZE); > + > if ((kexec_segment_size == ULONG_MAX) || > ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) { > pr_err("Binary measurement list too large.\n"); With the changes to Kconfig: Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
On 1/28/2025 7:18 AM, Stefan Berger wrote: > > > On 1/24/25 5:55 PM, steven chen wrote: >> The extra memory allocated for carrying the IMA measurement list across >> kexec is hard-coded as half a PAGE. Make it configurable. >> >> Define a Kconfig option, IMA_KEXEC_EXTRA_MEMORY_KB, to configure the >> extra memory (in kb) to be allocated for IMA measurements added during >> kexec soft reboot. Ensure the default value of the option is set such >> that extra half a page of memory for additional measurements is >> allocated >> for the additional measurements. >> >> Update ima_add_kexec_buffer() function to allocate memory based on the >> Kconfig option value, rather than the currently hard-coded one. >> >> From: Tushar Sugandhi <tusharsu@linux.microsoft.com> >> Author: Tushar Sugandhi <tusharsu@linux.microsoft.com> >> Suggested-by: Stefan Berger <stefanb@linux.ibm.com> >> Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> >> Signed-off-by: steven chen <chenste@linux.microsoft.com> >> --- >> security/integrity/ima/Kconfig | 10 ++++++++++ >> security/integrity/ima/ima_kexec.c | 16 ++++++++++------ >> 2 files changed, 20 insertions(+), 6 deletions(-) >> >> diff --git a/security/integrity/ima/Kconfig >> b/security/integrity/ima/Kconfig >> index 475c32615006..7dd2ed8b2cdc 100644 >> --- a/security/integrity/ima/Kconfig >> +++ b/security/integrity/ima/Kconfig >> @@ -321,4 +321,14 @@ config IMA_DISABLE_HTABLE >> help >> This option disables htable to allow measurement of >> duplicate records. >> +config IMA_KEXEC_EXTRA_MEMORY_KB >> + int > > int "Extra memory for IMA measurements added during kexec soft reboot" > > Without the description I wasn't able to modify the value. > >> + depends on IMA_KEXEC >> + default 0 >> + help >> + IMA_KEXEC_EXTRA_MEMORY_KB determines the extra memory to be >> + allocated (in kb) for IMA measurements added during kexec soft >> reboot. >> + If set to the default value, an extra half a page of memory >> for those >> + additional measurements will be allocated. >> + >> endif >> diff --git a/security/integrity/ima/ima_kexec.c >> b/security/integrity/ima/ima_kexec.c >> index d5f004cfeaec..c9c916f69ca7 100644 >> --- a/security/integrity/ima/ima_kexec.c >> +++ b/security/integrity/ima/ima_kexec.c >> @@ -128,22 +128,26 @@ void ima_add_kexec_buffer(struct kimage *image) >> .buf_min = 0, .buf_max = ULONG_MAX, >> .top_down = true }; >> unsigned long binary_runtime_size; >> - >> + unsigned long extra_size; >> /* use more understandable variable names than defined in kbuf */ >> void *kexec_buffer = NULL; >> size_t kexec_buffer_size = 0; >> int ret; >> /* >> - * Reserve an extra half page of memory for additional measurements >> - * added during the kexec load. >> + * Reserve extra memory for measurements added during kexec. >> */ >> - binary_runtime_size = ima_get_binary_runtime_size(); >> + if (CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB <= 0) >> + extra_size = PAGE_SIZE / 2; >> + else >> + extra_size = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024; >> + binary_runtime_size = ima_get_binary_runtime_size() + extra_size; >> + >> if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) >> kexec_segment_size = ULONG_MAX; >> else >> - kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + >> - PAGE_SIZE / 2, PAGE_SIZE); >> + kexec_segment_size = ALIGN(binary_runtime_size, PAGE_SIZE); >> + >> if ((kexec_segment_size == ULONG_MAX) || >> ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) { >> pr_err("Binary measurement list too large.\n"); > > With the changes to Kconfig: > > > Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> > Thanks, will update in the next release
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 475c32615006..7dd2ed8b2cdc 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -321,4 +321,14 @@ config IMA_DISABLE_HTABLE help This option disables htable to allow measurement of duplicate records. +config IMA_KEXEC_EXTRA_MEMORY_KB + int + depends on IMA_KEXEC + default 0 + help + IMA_KEXEC_EXTRA_MEMORY_KB determines the extra memory to be + allocated (in kb) for IMA measurements added during kexec soft reboot. + If set to the default value, an extra half a page of memory for those + additional measurements will be allocated. + endif diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index d5f004cfeaec..c9c916f69ca7 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -128,22 +128,26 @@ void ima_add_kexec_buffer(struct kimage *image) .buf_min = 0, .buf_max = ULONG_MAX, .top_down = true }; unsigned long binary_runtime_size; - + unsigned long extra_size; /* use more understandable variable names than defined in kbuf */ void *kexec_buffer = NULL; size_t kexec_buffer_size = 0; int ret; /* - * Reserve an extra half page of memory for additional measurements - * added during the kexec load. + * Reserve extra memory for measurements added during kexec. */ - binary_runtime_size = ima_get_binary_runtime_size(); + if (CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB <= 0) + extra_size = PAGE_SIZE / 2; + else + extra_size = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024; + binary_runtime_size = ima_get_binary_runtime_size() + extra_size; + if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) kexec_segment_size = ULONG_MAX; else - kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + - PAGE_SIZE / 2, PAGE_SIZE); + kexec_segment_size = ALIGN(binary_runtime_size, PAGE_SIZE); + if ((kexec_segment_size == ULONG_MAX) || ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) { pr_err("Binary measurement list too large.\n");