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| author |   Steven Chen <chenste@linux.microsoft.com> | 2025-04-21 15:25:14 -0700 |
|---|---|---|
| committer |   Mimi Zohar <zohar@linux.ibm.com> | 2025-04-29 15:54:54 -0400 |
| commit | 0ad93987c9c10a3125a58da0f225241169f3271a (patch) | |
| tree | d8430e0cd66ecb646710c60fbf48c220552b133f /security | |
| parent | ima: verify if the segment size has changed (diff) | |
| download | linux-rng-0ad93987c9c10a3125a58da0f225241169f3271a.tar.xz linux-rng-0ad93987c9c10a3125a58da0f225241169f3271a.zip | |
ima: make the kexec extra memory configurable
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.
Suggested-by: Stefan Berger <stefanb@linux.ibm.com>
Co-developed-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Steven Chen <chenste@linux.microsoft.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com> # ppc64/kvm
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/ima/Kconfig | 11 | ||||
| -rw-r--r-- | security/integrity/ima/ima_kexec.c | 16 |
2 files changed, 22 insertions, 5 deletions
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 475c32615006..976e75f9b9ba 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -321,4 +321,15 @@ config IMA_DISABLE_HTABLE help This option disables htable to allow measurement of duplicate records. +config IMA_KEXEC_EXTRA_MEMORY_KB + int "Extra memory for IMA measurements added during kexec soft reboot" + range 0 40 + 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 of 0, an extra half 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 ed867734ee70..d1c9d369ba08 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -118,6 +118,7 @@ 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_memory; /* use more understandable variable names than defined in kbuf */ size_t kexec_buffer_size = 0; @@ -125,15 +126,20 @@ void ima_add_kexec_buffer(struct kimage *image) 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_memory = PAGE_SIZE / 2; + else + extra_memory = CONFIG_IMA_KEXEC_EXTRA_MEMORY_KB * 1024; + + binary_runtime_size = ima_get_binary_runtime_size() + extra_memory; + 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"); |