From: Tushar Sugandhi <tusharsu@linux.microsoft.com>
To: Stefan Berger <stefanb@linux.ibm.com>,
zohar@linux.ibm.com, roberto.sassu@huaweicloud.com,
roberto.sassu@huawei.com, eric.snowberg@oracle.com,
ebiederm@xmission.com, noodles@fb.com, bauermann@kolabnow.com,
linux-integrity@vger.kernel.org, kexec@lists.infradead.org
Cc: code@tyhicks.com, nramas@linux.microsoft.com, paul@paul-moore.com
Subject: Re: [PATCH v4 2/7] kexec: define functions to map and unmap segments
Date: Tue, 23 Jan 2024 12:39:41 -0800 [thread overview]
Message-ID: <9c71454b-ba41-4725-9fb7-0602b1a656c1@linux.microsoft.com> (raw)
In-Reply-To: <e375cd83-f424-4b0e-96e3-7a47a4f70715@linux.ibm.com>
Thanks Stefan for taking a look.
On 1/23/24 09:03, Stefan Berger wrote:
>
>
> On 1/22/24 13:37, Tushar Sugandhi wrote:
>> Implement kimage_map_segment() to enable mapping of IMA buffer source
>> pages to the kimage structure post kexec 'load'. This function,
>> accepting a kimage pointer, an address, and a size, will gather the
>> source pages within the specified address range, create an array of page
>> pointers, and map these to a contiguous virtual address range. The
>> function returns the start of this range if successful, or NULL if
>> unsuccessful.
>>
>> Implement kimage_unmap_segment() for unmapping segments
>> using vunmap(). Relocate 'for_each_kimage_entry()' macro from
>> kexec_core.c to kexec.h for broader accessibility.
>>
>> Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
>> ---
>> include/linux/kexec.h | 13 +++++++
>> kernel/kexec_core.c | 59 +++++++++++++++++++++++++++---
>> security/integrity/ima/ima_kexec.c | 1 +
>> 3 files changed, 68 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>> index 22b5cd24f581..e00b8101b53b 100644
>> --- a/include/linux/kexec.h
>> +++ b/include/linux/kexec.h
>> @@ -490,6 +490,15 @@ static inline int
>> arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, g
>> static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned
>> int pages) { }
>> #endif
>> +#define for_each_kimage_entry(image, ptr, entry) \
>> + for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
>> + ptr = (entry & IND_INDIRECTION) ? \
>> + boot_phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
>> +
>> +extern void *kimage_map_segment(struct kimage *image,
>> + unsigned long addr, unsigned long size);
>> +extern void kimage_unmap_segment(void *buffer);
>> +
>
> This series applies to v6.5. You may want to rebase to 6.7.
>
Will rebase. Thanks for catching this.
>> #else /* !CONFIG_KEXEC_CORE */
>> struct pt_regs;
>> struct task_struct;
>> @@ -497,6 +506,10 @@ static inline void __crash_kexec(struct pt_regs
>> *regs) { }
>> static inline void crash_kexec(struct pt_regs *regs) { }
>> static inline int kexec_should_crash(struct task_struct *p) { return
>> 0; }
>> static inline int kexec_crash_loaded(void) { return 0; }
>> +static inline void *kimage_map_segment(struct kimage *image,
>> + unsigned long addr, unsigned long size)
>> +{ return NULL; }
>> +static inline void kimage_unmap_segment(void *buffer) { }
>> #define kexec_in_progress false
>> #endif /* CONFIG_KEXEC_CORE */
>> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
>> index 3d578c6fefee..26978ad02676 100644
>> --- a/kernel/kexec_core.c
>> +++ b/kernel/kexec_core.c
>> @@ -594,11 +594,6 @@ void kimage_terminate(struct kimage *image)
>> *image->entry = IND_DONE;
>> }
>> -#define for_each_kimage_entry(image, ptr, entry) \
>> - for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
>> - ptr = (entry & IND_INDIRECTION) ? \
>> - boot_phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
>> -
>> static void kimage_free_entry(kimage_entry_t entry)
>> {
>> struct page *page;
>> @@ -921,6 +916,60 @@ int kimage_load_segment(struct kimage *image,
>> return result;
>> }
>> +void *kimage_map_segment(struct kimage *image,
>> + unsigned long addr, unsigned long size)
>> +{
>> + unsigned long eaddr = addr + size;
>> + unsigned long src_page_addr, dest_page_addr;
>> + unsigned int npages;
>> + struct page **src_pages;
>> + int i;
>> + kimage_entry_t *ptr, entry;
>> + void *vaddr = NULL;
>> +
>> + /*
>> + * Collect the source pages and map them in a contiguous VA range.
>> + */
>> + npages = PFN_UP(eaddr) - PFN_DOWN(addr);
>> + src_pages = kmalloc_array(npages, sizeof(*src_pages), GFP_KERNEL);
>> + if (!src_pages) {
>> + pr_err("%s: Could not allocate ima pages array.\n", __func__);
>> + return NULL;
>> + }
>> +
>> + i = 0;
>> + for_each_kimage_entry(image, ptr, entry) {
>> + if (entry & IND_DESTINATION)
>> + dest_page_addr = entry & PAGE_MASK;
>> + else if (entry & IND_SOURCE) {
>> + if (dest_page_addr >= addr && dest_page_addr < eaddr) {
>> + src_page_addr = entry & PAGE_MASK;
>> + src_pages[i++] =
>> + virt_to_page(__va(src_page_addr));
>> + if (i == npages)
>> + break;
>> + dest_page_addr += PAGE_SIZE;
>> + }
>> + }
>> + }
>> +
>> + /* Sanity check. */
>> + WARN_ON(i < npages);
>> +
>> + vaddr = vmap(src_pages, npages, VM_MAP, PAGE_KERNEL);
>> + kfree(src_pages);
>> +
>> + if (!vaddr)
>> + pr_err("%s: Could not map imap buffer.\n", __func__);
>
> imap -> ima
>
Good eye catching this.
Will fix.
>> +
>> + return vaddr;
>> +}
>> +
>> +void kimage_unmap_segment(void *segment_buffer)
>> +{
>> + vunmap(segment_buffer);
>> +}
>> +
>> struct kexec_load_limit {
>> /* Mutex protects the limit count. */
>> struct mutex mutex;
>> diff --git a/security/integrity/ima/ima_kexec.c
>> b/security/integrity/ima/ima_kexec.c
>> index 99daac355c70..4f944c9b4168 100644
>> --- a/security/integrity/ima/ima_kexec.c
>> +++ b/security/integrity/ima/ima_kexec.c
>> @@ -170,6 +170,7 @@ void ima_add_kexec_buffer(struct kimage *image)
>> pr_debug("kexec measurement buffer for the loaded kernel at
>> 0x%lx.\n",
>> kbuf.mem);
>> }
>> +
>
> remove
>
Will do.
~Tushar
>> #endif /* IMA_KEXEC */
>> /*
next prev parent reply other threads:[~2024-01-23 20:39 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-22 18:37 [PATCH v4 0/7] ima: kexec: measure events between kexec load and execute Tushar Sugandhi
2024-01-22 18:37 ` [PATCH v4 1/7] ima: define and call ima_alloc_kexec_file_buf Tushar Sugandhi
2024-01-24 2:54 ` Stefan Berger
2024-01-24 3:38 ` Stefan Berger
2024-01-26 22:14 ` Tushar Sugandhi
2024-01-24 13:33 ` Mimi Zohar
2024-01-25 19:03 ` Tushar Sugandhi
2024-01-22 18:37 ` [PATCH v4 2/7] kexec: define functions to map and unmap segments Tushar Sugandhi
2024-01-23 17:03 ` Stefan Berger
2024-01-23 20:39 ` Tushar Sugandhi [this message]
2024-01-22 18:38 ` [PATCH v4 3/7] ima: kexec: skip IMA segment validation after kexec soft reboot Tushar Sugandhi
2024-01-22 18:38 ` [PATCH v4 4/7] ima: kexec: move ima log copy from kexec load to execute Tushar Sugandhi
2024-01-24 16:11 ` Mimi Zohar
2024-01-25 19:06 ` Tushar Sugandhi
2024-01-22 18:38 ` [PATCH v4 5/7] ima: suspend measurements during buffer copy at kexec execute Tushar Sugandhi
2024-01-23 18:18 ` Stefan Berger
2024-01-23 20:55 ` Tushar Sugandhi
2024-01-22 18:38 ` [PATCH v4 6/7] ima: make the kexec extra memory configurable Tushar Sugandhi
2024-01-23 19:02 ` Stefan Berger
2024-01-23 21:19 ` Tushar Sugandhi
2024-01-24 1:48 ` Stefan Berger
2024-01-24 14:07 ` Mimi Zohar
2024-01-25 19:14 ` Tushar Sugandhi
2024-01-22 18:38 ` [PATCH v4 7/7] ima: measure kexec load and exec events as critical data Tushar Sugandhi
2024-01-24 14:35 ` Mimi Zohar
2024-01-25 19:16 ` Tushar Sugandhi
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