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SubjectRe: [PATCH] x86, kdump: Fix efi=noruntime NULL pointer dereference
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On Fri, 2018-08-10 at 18:28 +0800, Dave Young wrote:
>
> > @@ -250,8 +253,10 @@ setup_boot_parameters(struct kimage *image, struct boot_params *params,
> >
> > #ifdef CONFIG_EFI
> > /* Setup EFI state */
> > - setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
> > + ret = setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
> > efi_setup_data_offset);
> > + if (ret)
>
> Here should check efi_enabled(EFI_BOOT) && ret

Patch with that works for me.

> In case efi boot we need the efi info set correctly, or one need pass
> acpi_rsdp= in kernel cmdline param.
>
> Still not sure how to allow one to workaround it by using acpi_rsdp=
> param with kexec_file_load..

Does this improve things, and plug the no boot hole?

x86, kdump: cleanup efi setup data handling a bit

1. Remove efi specific variables from bzImage64_load() other than the
one it needs, efi_map_sz, passing it and params_cmdline_sz on to efi
setup functions, giving them all they need without duplication.

2. Only allocate space for efi setup data when a 1:1 mapping is available.
Bail early with -ENODEV if not available, but is required to boot, and
acpi_rsdp= was not passed on the command line.

3. Use the proper config dependency to isolate efi setup functions,
adding a !EFI_RUNTIME_MAP stub for setup_efi_state().

4. Change efi functions that cannot fail to void.

Signed-off-by: Mike Galbraith <efault@gmx.de>
---
arch/x86/kernel/kexec-bzimage64.c | 99 +++++++++++++++++---------------------
1 file changed, 45 insertions(+), 54 deletions(-)

--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -112,35 +112,32 @@ static int setup_e820_entries(struct boo
return 0;
}

-#ifdef CONFIG_EFI
-static int setup_efi_info_memmap(struct boot_params *params,
+#ifdef CONFIG_EFI_RUNTIME_MAP
+static void setup_efi_info_memmap(struct boot_params *params,
unsigned long params_load_addr,
- unsigned int efi_map_offset,
+ unsigned int params_cmdline_sz,
unsigned int efi_map_sz)
{
- void *efi_map = (void *)params + efi_map_offset;
- unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
+ void *efi_map = (void *)params + params_cmdline_sz;
+ unsigned long efi_map_phys_addr = params_load_addr + params_cmdline_sz;
struct efi_info *ei = &params->efi_info;

- if (!efi_map_sz)
- return -EINVAL;
-
efi_runtime_map_copy(efi_map, efi_map_sz);

ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
ei->efi_memmap_hi = efi_map_phys_addr >> 32;
ei->efi_memmap_size = efi_map_sz;
-
- return 0;
}

-static int
+static void
prepare_add_efi_setup_data(struct boot_params *params,
- unsigned long params_load_addr,
- unsigned int efi_setup_data_offset)
+ unsigned long params_load_addr,
+ unsigned int params_cmdline_sz,
+ unsigned int efi_map_sz)
{
+ unsigned int data_offset = params_cmdline_sz + ALIGN(efi_map_sz, 16);
unsigned long setup_data_phys;
- struct setup_data *sd = (void *)params + efi_setup_data_offset;
+ struct setup_data *sd = (void *)params + data_offset;
struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);

esd->fw_vendor = efi.fw_vendor;
@@ -152,33 +149,20 @@ prepare_add_efi_setup_data(struct boot_p
sd->len = sizeof(struct efi_setup_data);

/* Add setup data */
- setup_data_phys = params_load_addr + efi_setup_data_offset;
+ setup_data_phys = params_load_addr + data_offset;
sd->next = params->hdr.setup_data;
params->hdr.setup_data = setup_data_phys;
-
- return 0;
}

static int
setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
- unsigned int efi_map_offset, unsigned int efi_map_sz,
- unsigned int efi_setup_data_offset)
+ unsigned int params_cmdline_sz, unsigned int efi_map_sz)
{
struct efi_info *current_ei = &boot_params.efi_info;
struct efi_info *ei = &params->efi_info;
- int ret;
-
- if (!current_ei->efi_memmap_size)
- return -EINVAL;

- /*
- * If 1:1 mapping is not enabled, second kernel can not setup EFI
- * and use EFI run time services. User space will have to pass
- * acpi_rsdp=<addr> on kernel command line to make second kernel boot
- * without efi.
- */
- if (efi_enabled(EFI_OLD_MEMMAP) || !efi_enabled(EFI_RUNTIME_SERVICES))
- return -ENODEV;
+ if (!efi_map_sz || !current_ei->efi_memmap_size)
+ return efi_map_sz ? -EINVAL : 0;

ei->efi_loader_signature = current_ei->efi_loader_signature;
ei->efi_systab = current_ei->efi_systab;
@@ -187,21 +171,24 @@ setup_efi_state(struct boot_params *para
ei->efi_memdesc_version = current_ei->efi_memdesc_version;
ei->efi_memdesc_size = efi_get_runtime_map_desc_size();

- ret = setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
+ setup_efi_info_memmap(params, params_load_addr, params_cmdline_sz,
efi_map_sz);
- if (ret)
- return ret;
- prepare_add_efi_setup_data(params, params_load_addr,
- efi_setup_data_offset);
+ prepare_add_efi_setup_data(params, params_load_addr, params_cmdline_sz,
+ efi_map_sz);
return 0;
}
-#endif /* CONFIG_EFI */
+#else /* !CONFIG_EFI_RUNTIME_MAP */
+static int
+setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
+ unsigned int params_cmdline_sz, unsigned int efi_map_sz)
+{ return 0; }
+#endif /* CONFIG_EFI_RUNTIME_MAP */

static int
setup_boot_parameters(struct kimage *image, struct boot_params *params,
unsigned long params_load_addr,
- unsigned int efi_map_offset, unsigned int efi_map_sz,
- unsigned int efi_setup_data_offset)
+ unsigned int params_cmdline_sz,
+ unsigned int efi_map_sz)
{
unsigned int nr_e820_entries;
unsigned long long mem_k, start, end;
@@ -251,13 +238,9 @@ setup_boot_parameters(struct kimage *ima
}
}

-#ifdef CONFIG_EFI
- /* Setup EFI state */
- ret = setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
- efi_setup_data_offset);
- if (efi_enabled(EFI_BOOT) && ret)
+ ret = setup_efi_state(params, params_load_addr, params_cmdline_sz, efi_map_sz);
+ if (ret)
return ret;
-#endif

/* Setup EDD info */
memcpy(params->eddbuf, boot_params.eddbuf,
@@ -343,7 +326,7 @@ static void *bzImage64_load(struct kimag
struct kexec_entry64_regs regs64;
void *stack;
unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
- unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
+ unsigned int efi_map_sz = 0;
struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
.top_down = true };
struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
@@ -402,19 +385,28 @@ static void *bzImage64_load(struct kimag
* have to create separate segment for each. Keeps things
* little bit simple
*/
- efi_map_sz = efi_get_runtime_map_size();
params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
MAX_ELFCOREHDR_STR_LEN;
params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
- kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
- sizeof(struct setup_data) +
- sizeof(struct efi_setup_data);
+ kbuf.bufsz = params_cmdline_sz + sizeof(struct setup_data);
+
+ /*
+ * If a 1:1 mapping does not exist, the second kernel cannot setup
+ * and use EFI run time services, user space will have to pass
+ * acpi_rsdp=<addr> on the kernel command line to make the second
+ * kernel boot without efi. Allocate space for efi setup data if
+ * this constraint is met, bail if not, but is required to boot,
+ * and acpi_rsdp=<addr> was not passed on the command line.
+ */
+ if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_OLD_MEMMAP)) {
+ efi_map_sz = efi_get_runtime_map_size();
+ kbuf.bufsz += ALIGN(efi_map_sz, 16) + sizeof(struct efi_setup_data);
+ } else if (efi_enabled(EFI_BOOT) && !strstr(cmdline, "acpi_rsdp="))
+ return ERR_PTR(-ENODEV);

params = kzalloc(kbuf.bufsz, GFP_KERNEL);
if (!params)
return ERR_PTR(-ENOMEM);
- efi_map_offset = params_cmdline_sz;
- efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);

/* Copy setup header onto bootparams. Documentation/x86/boot.txt */
setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
@@ -494,8 +486,7 @@ static void *bzImage64_load(struct kimag
goto out_free_params;

ret = setup_boot_parameters(image, params, bootparam_load_addr,
- efi_map_offset, efi_map_sz,
- efi_setup_data_offset);
+ params_cmdline_sz, efi_map_sz);
if (ret)
goto out_free_params;

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