| Message ID | 9D0C961D-9999-4C41-A44B-22FEAF0DAB7F@live.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | efi: Do not import certificates from UEFI Secure Boot for T2 Macs | expand |
From: Aditya Garg > Sent: 09 February 2022 14:28 > > On T2 Macs, the secure boot is handled by the T2 Chip. If enabled, only > macOS and Windows are allowed to boot on these machines. Thus we need to > disable secure boot for Linux. If we boot into Linux after disabling > secure boot, if CONFIG_LOAD_UEFI_KEYS is enabled, EFI Runtime services > fail to start, with the following logs in dmesg > .. > +static const struct dmi_system_id uefi_apple_ignore[] = { > + { > + .matches = { > + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), > + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,1"), > + }, I think I'd use: #define xxx(vendor, product) \ .matches = { DMI_MATCH(DMI_BOARD_VENDOR, vendor), \ DMI_MATCH(DMI_PRODUCT_NAME, product), \ } somewhere with a suitable name (bikeshed blue) to reduce the code size of this table. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Wed, Feb 09, 2022 at 02:27:51PM +0000, Aditya Garg wrote: > From: Aditya Garg <gargaditya08@live.com> > > On T2 Macs, the secure boot is handled by the T2 Chip. If enabled, only > macOS and Windows are allowed to boot on these machines. Thus we need to > disable secure boot for Linux. If we boot into Linux after disabling > secure boot, if CONFIG_LOAD_UEFI_KEYS is enabled, EFI Runtime services > fail to start, with the following logs in dmesg Which specific variable request is triggering the failure? Do any runtime variable accesses work on these machines?
> On 09-Feb-2022, at 10:19 PM, Matthew Garrett <mjg59@srcf.ucam.org> wrote: > > On Wed, Feb 09, 2022 at 02:27:51PM +0000, Aditya Garg wrote: >> From: Aditya Garg <gargaditya08@live.com> >> >> On T2 Macs, the secure boot is handled by the T2 Chip. If enabled, only >> macOS and Windows are allowed to boot on these machines. Thus we need to >> disable secure boot for Linux. If we boot into Linux after disabling >> secure boot, if CONFIG_LOAD_UEFI_KEYS is enabled, EFI Runtime services >> fail to start, with the following logs in dmesg > > Which specific variable request is triggering the failure? Do any > runtime variable accesses work on these machines? Commit f5390cd0b43c2e54c7cf5506c7da4a37c5cef746 in Linus’ tree was also added to force EFI v1.1 on these machines, since v2.4, reported by them was causing kernel panics. So, EFI 1.1 without import certificates seems to work and have been able to modify the variables, thus the remaining EFI variable accesses seem to work.
On Wed, Feb 09, 2022 at 06:02:34PM +0000, Aditya Garg wrote: > > > > On 09-Feb-2022, at 10:19 PM, Matthew Garrett <mjg59@srcf.ucam.org> wrote: > > > > On Wed, Feb 09, 2022 at 02:27:51PM +0000, Aditya Garg wrote: > >> From: Aditya Garg <gargaditya08@live.com> > >> > >> On T2 Macs, the secure boot is handled by the T2 Chip. If enabled, only > >> macOS and Windows are allowed to boot on these machines. Thus we need to > >> disable secure boot for Linux. If we boot into Linux after disabling > >> secure boot, if CONFIG_LOAD_UEFI_KEYS is enabled, EFI Runtime services > >> fail to start, with the following logs in dmesg > > > > Which specific variable request is triggering the failure? Do any > > runtime variable accesses work on these machines? > Commit f5390cd0b43c2e54c7cf5506c7da4a37c5cef746 in Linus’ tree was also added to force EFI v1.1 on these machines, since v2.4, reported by them was causing kernel panics. > > So, EFI 1.1 without import certificates seems to work and have been able to modify the variables, thus the remaining EFI variable accesses seem to work. The LOAD_UEFI_KEYS code isn't doing anything special here - it's just trying to read some variables. If we simply disable that then the expectation would be that reading the same variables from userland would trigger the same failure. So the question is which of the variables that LOAD_UEFI_KEYS accesses is triggering the failure, and what's special about that? If it's a specific variable GUID or name that's failing, we should block that on Apple hardware in order to avoid issues caused by userland performing equivalent accesses.
On Wed, Feb 09, 2022 at 06:35:45PM +0000, Matthew Garrett wrote: > The LOAD_UEFI_KEYS code isn't doing anything special here - it's just > trying to read some variables. If we simply disable that then the > expectation would be that reading the same variables from userland would > trigger the same failure. So the question is which of the variables that > LOAD_UEFI_KEYS accesses is triggering the failure, and what's special > about that? If it's a specific variable GUID or name that's failing, we > should block that on Apple hardware in order to avoid issues caused by > userland performing equivalent accesses. ie, can you try something like this? diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c index f3e54f6616f0..01cbd4811d1e 100644 --- a/drivers/firmware/efi/runtime-wrappers.c +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -32,6 +32,8 @@ #include <linux/stringify.h> #include <linux/workqueue.h> #include <linux/completion.h> +#include <linux/ucs2_string.h> +#include <linux/slab.h> #include <asm/efi.h> @@ -203,6 +205,21 @@ static void efi_call_rts(struct work_struct *work) (efi_time_t *)arg2); break; case EFI_GET_VARIABLE: + unsigned long utf8_name_size; + char *utf8_name; + char guid_str[sizeof(efi_guid_t)+1]; + + utf8_name_size = ucs2_utf8size((efi_char16_t *)arg1); + utf8_name = kmalloc(utf8_name_size+1, GFP_KERNEL); + if (!utf8_name) { + printk(KERN_INFO "failed to allocate UTF8 buffer\n"); + break; + } + + ucs2_as_utf8(utf8_name, (efi_char16_t *)arg1, utf8_name_size + 1); + efi_guid_to_str((efi_guid_t *)arg2, guid_str); + + printk(KERN_INFO "Reading EFI variable %s-%s\n", utf8_name, guid_str); status = efi_call_virt(get_variable, (efi_char16_t *)arg1, (efi_guid_t *)arg2, (u32 *)arg3, (unsigned long *)arg4, (void *)arg5);
> ie, can you try something like this? > > diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c > index f3e54f6616f0..01cbd4811d1e 100644 > --- a/drivers/firmware/efi/runtime-wrappers.c > +++ b/drivers/firmware/efi/runtime-wrappers.c > @@ -32,6 +32,8 @@ > #include <linux/stringify.h> > #include <linux/workqueue.h> > #include <linux/completion.h> > +#include <linux/ucs2_string.h> > +#include <linux/slab.h> > > #include <asm/efi.h> > > @@ -203,6 +205,21 @@ static void efi_call_rts(struct work_struct *work) > (efi_time_t *)arg2); > break; > case EFI_GET_VARIABLE: > + unsigned long utf8_name_size; > + char *utf8_name; > + char guid_str[sizeof(efi_guid_t)+1]; > + > + utf8_name_size = ucs2_utf8size((efi_char16_t *)arg1); > + utf8_name = kmalloc(utf8_name_size+1, GFP_KERNEL); > + if (!utf8_name) { > + printk(KERN_INFO "failed to allocate UTF8 buffer\n"); > + break; > + } > + > + ucs2_as_utf8(utf8_name, (efi_char16_t *)arg1, utf8_name_size + 1); > + efi_guid_to_str((efi_guid_t *)arg2, guid_str); > + > + printk(KERN_INFO "Reading EFI variable %s-%s\n", utf8_name, guid_str); > status = efi_call_virt(get_variable, (efi_char16_t *)arg1, > (efi_guid_t *)arg2, (u32 *)arg3, > (unsigned long *)arg4, (void *)arg5); > Hi Matthew I haven't tested this yet (Kernel is compiling) but I have found out that this part of the code is causing a crash static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid, unsigned long *size, efi_status_t *status) { unsigned long lsize = 4; unsigned long tmpdb[4]; void *db; *status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb); if (*status == EFI_NOT_FOUND) return NULL; if (*status != EFI_BUFFER_TOO_SMALL) { pr_err("Couldn't get size: 0x%lx\n", *status); return NULL; } db = kmalloc(lsize, GFP_KERNEL); if (!db) return NULL; *status = efi.get_variable(name, guid, NULL, &lsize, db); if (*status != EFI_SUCCESS) { kfree(db); pr_err("Error reading db var: 0x%lx\n", *status); return NULL; } *size = lsize; return db; } If I remove the return 0 I had added from other 3 left functions, crash doesn't occur. When the kernel compiles with your patch, I’ll send whatever I get. Regards Aditya
> ie, can you try something like this? > > diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c > index f3e54f6616f0..01cbd4811d1e 100644 > --- a/drivers/firmware/efi/runtime-wrappers.c > +++ b/drivers/firmware/efi/runtime-wrappers.c > @@ -32,6 +32,8 @@ > #include <linux/stringify.h> > #include <linux/workqueue.h> > #include <linux/completion.h> > +#include <linux/ucs2_string.h> > +#include <linux/slab.h> > > #include <asm/efi.h> > > @@ -203,6 +205,21 @@ static void efi_call_rts(struct work_struct *work) > (efi_time_t *)arg2); > break; > case EFI_GET_VARIABLE: > + unsigned long utf8_name_size; > + char *utf8_name; > + char guid_str[sizeof(efi_guid_t)+1]; > + > + utf8_name_size = ucs2_utf8size((efi_char16_t *)arg1); > + utf8_name = kmalloc(utf8_name_size+1, GFP_KERNEL); > + if (!utf8_name) { > + printk(KERN_INFO "failed to allocate UTF8 buffer\n"); > + break; > + } > + > + ucs2_as_utf8(utf8_name, (efi_char16_t *)arg1, utf8_name_size + 1); > + efi_guid_to_str((efi_guid_t *)arg2, guid_str); > + > + printk(KERN_INFO "Reading EFI variable %s-%s\n", utf8_name, guid_str); > status = efi_call_virt(get_variable, (efi_char16_t *)arg1, > (efi_guid_t *)arg2, (u32 *)arg3, > (unsigned long *)arg4, (void *)arg5); Looks like there is some error in this patch drivers/firmware/efi/runtime-wrappers.c:208:3: error: a label can only be part of a statement and a declaration is not a statement 208 | unsigned long utf8_name_size; | ^~~~~~~~ drivers/firmware/efi/runtime-wrappers.c:209:3: error: expected expression before ‘char’ 209 | char *utf8_name; | ^~~~ drivers/firmware/efi/runtime-wrappers.c:210:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] 210 | char guid_str[sizeof(efi_guid_t)+1]; | ^~~~ drivers/firmware/efi/runtime-wrappers.c:213:3: error: ‘utf8_name’ undeclared (first use in this function) 213 | utf8_name = kmalloc(utf8_name_size+1, GFP_KERNEL); | ^~~~~~~~~ drivers/firmware/efi/runtime-wrappers.c:213:3: note: each undeclared identifier is reported only once for each function it appears in make[6]: *** [scripts/Makefile.build:287: drivers/firmware/efi/runtime-wrappers.o] Error 1 make[5]: *** [scripts/Makefile.build:549: drivers/firmware/efi] Error 2 make[4]: *** [scripts/Makefile.build:549: drivers/firmware] Error 2 make[4]: *** Waiting for unfinished jobs....
> > The LOAD_UEFI_KEYS code isn't doing anything special here - it's just > trying to read some variables. If we simply disable that then the > expectation would be that reading the same variables from userland would > trigger the same failure. So the question is which of the variables that > LOAD_UEFI_KEYS accesses is triggering the failure, and what's special > about that? If it's a specific variable GUID or name that's failing, we > should block that on Apple hardware in order to avoid issues caused by > userland performing equivalent accesses. The size log seems to be extra when crash occurs integrity: Couldn't get size: 0x8000000000000015 integrity: MODSIGN: Couldn't get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get UEFI dbx list integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get mokx list integrity: Couldn't get size: 0x80000000
> On 09-Feb-2022, at 9:09 PM, David Laight <David.Laight@ACULAB.COM> wrote: > > From: Aditya Garg >> Sent: 09 February 2022 14:28 >> >> On T2 Macs, the secure boot is handled by the T2 Chip. If enabled, only >> macOS and Windows are allowed to boot on these machines. Thus we need to >> disable secure boot for Linux. If we boot into Linux after disabling >> secure boot, if CONFIG_LOAD_UEFI_KEYS is enabled, EFI Runtime services >> fail to start, with the following logs in dmesg >> > .. >> +static const struct dmi_system_id uefi_apple_ignore[] = { >> + { >> + .matches = { >> + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), >> + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,1"), >> + }, > > I think I'd use: > #define xxx(vendor, product) \ > .matches = { > DMI_MATCH(DMI_BOARD_VENDOR, vendor), \ > DMI_MATCH(DMI_PRODUCT_NAME, product), \ > } > somewhere with a suitable name (bikeshed blue) to reduce > the code size of this table. > Alright, I’ll send a v2 with this addressed. > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) >
On Thu, Feb 10, 2022 at 05:49:50AM +0000, Aditya Garg wrote:
> Looks like there is some error in this patch
I'm sorry, I'd build tested it here but clearly screwed that up. Try
this one?
diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index f3e54f6616f0..18b2ab40bee5 100644
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -32,6 +32,8 @@
#include <linux/stringify.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
+#include <linux/ucs2_string.h>
+#include <linux/slab.h>
#include <asm/efi.h>
@@ -179,6 +181,9 @@ static void efi_call_rts(struct work_struct *work)
{
void *arg1, *arg2, *arg3, *arg4, *arg5;
efi_status_t status = EFI_NOT_FOUND;
+ unsigned long utf8_name_size;
+ char *utf8_name;
+ char guid_str[sizeof(efi_guid_t)+1];
arg1 = efi_rts_work.arg1;
arg2 = efi_rts_work.arg2;
@@ -203,6 +208,17 @@ static void efi_call_rts(struct work_struct *work)
(efi_time_t *)arg2);
break;
case EFI_GET_VARIABLE:
+ utf8_name_size = ucs2_utf8size((efi_char16_t *)arg1);
+ utf8_name = kmalloc(utf8_name_size+1, GFP_KERNEL);
+ if (!utf8_name) {
+ printk(KERN_INFO "failed to allocate UTF8 buffer\n");
+ break;
+ }
+
+ ucs2_as_utf8(utf8_name, (efi_char16_t *)arg1, utf8_name_size + 1);
+ efi_guid_to_str((efi_guid_t *)arg2, guid_str);
+
+ printk(KERN_INFO "Reading EFI variable %s-%s\n", utf8_name, guid_str);
status = efi_call_virt(get_variable, (efi_char16_t *)arg1,
(efi_guid_t *)arg2, (u32 *)arg3,
(unsigned long *)arg4, (void *)arg5);
> > I'm sorry, I'd build tested it here but clearly screwed that up. Try > this one? > > With this patch, I built 2 kernels, one with CONFIG_LOAD_UEFI_KEYS=y and other with CONFIG_LOAD_UEFI_KEYS=n. I have got different variables causing panics in both cases. The logs couldn't get saved in journalctl so, I clicked a picture of the same. The kernel anyways was refusing to boot after these logs. With CONFIG_LOAD_UEFI_KEYS=y, this variable seems to be causing panics MokIgnoreDB-605dab50-e046-4300-abb6-3dd810dd8b23 The link of the logs :- https://gist.githubusercontent.com/AdityaGarg8/8e820c2724a65fb4bbb5deae2b358dc8/raw/2d3ef24c2b5025d500c5bebd418db5c185a47328/CONFIG_LOAD_UEFI_KEYS=y.jpeg With CONFIG_LOAD_UEFI_KEYS=n, this variable seems to be causing panics AppleSecureBootPolicy-94b73556-2197-4702-82a8-3e1337dafbfb The link of the logs :- https://gist.githubusercontent.com/AdityaGarg8/8e820c2724a65fb4bbb5deae2b358dc8/raw/2d3ef24c2b5025d500c5bebd418db5c185a47328/CONFIG_LOAD_UEFI_KEYS=n.jpeg
On Fri, Feb 11, 2022 at 04:51:22AM +0000, Aditya Garg wrote:
> With this patch, I built 2 kernels, one with CONFIG_LOAD_UEFI_KEYS=y and other with CONFIG_LOAD_UEFI_KEYS=n. I have got different variables causing panics in both cases. The logs couldn't get saved in journalctl so, I clicked a picture of the same. The kernel anyways was refusing to boot after these logs.
Oh gosh I'm an idiot. Please try this one instead.
diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index f3e54f6616f0..79a003c2f7b6 100644
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -32,6 +32,8 @@
#include <linux/stringify.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
+#include <linux/ucs2_string.h>
+#include <linux/slab.h>
#include <asm/efi.h>
@@ -179,6 +181,9 @@ static void efi_call_rts(struct work_struct *work)
{
void *arg1, *arg2, *arg3, *arg4, *arg5;
efi_status_t status = EFI_NOT_FOUND;
+ unsigned long utf8_name_size;
+ char *utf8_name;
+ char guid_str[UUID_STRING_LEN + 1];
arg1 = efi_rts_work.arg1;
arg2 = efi_rts_work.arg2;
@@ -203,6 +208,17 @@ static void efi_call_rts(struct work_struct *work)
(efi_time_t *)arg2);
break;
case EFI_GET_VARIABLE:
+ utf8_name_size = ucs2_utf8size((efi_char16_t *)arg1);
+ utf8_name = kmalloc(utf8_name_size+1, GFP_KERNEL);
+ if (!utf8_name) {
+ printk(KERN_INFO "failed to allocate UTF8 buffer\n");
+ break;
+ }
+
+ ucs2_as_utf8(utf8_name, (efi_char16_t *)arg1, utf8_name_size + 1);
+ efi_guid_to_str((efi_guid_t *)arg2, guid_str);
+
+ printk(KERN_INFO "Reading EFI variable %s-%s\n", utf8_name, guid_str);
status = efi_call_virt(get_variable, (efi_char16_t *)arg1,
(efi_guid_t *)arg2, (u32 *)arg3,
(unsigned long *)arg4, (void *)arg5);
> > Oh gosh I'm an idiot. Please try this one instead. > Looks like EFI variable MokIgnoreDB-605dab50-e046-4300-abb6-3dd810dd8b23 and EFI variable db-d719b2cb-3d3a-4596-a3bc-dad00e67656f are causing issues Feb 12 11:01:52 MacBook kernel: Reading EFI variable MokIgnoreDB-605dab50-e046-4300-abb6-3dd810dd8b23 Feb 12 11:01:52 MacBook kernel: Reading EFI variable db-d719b2cb-3d3a-4596-a3bc-dad00e67656f Feb 12 11:01:52 MacBook kernel: ------------[ cut here ]------------ Feb 12 11:01:52 MacBook kernel: [Firmware Bug]: Page fault caused by firmware at PA: 0xffffbc34c0068000 Feb 12 11:01:52 MacBook kernel: WARNING: CPU: 7 PID: 98 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0 Feb 12 11:01:52 MacBook kernel: Modules linked in: Feb 12 11:01:52 MacBook kernel: CPU: 7 PID: 98 Comm: kworker/u24:1 Not tainted 5.16.8-t2 #2 Feb 12 11:01:52 MacBook kernel: Hardware name: Apple Inc. MacBookPro16,1/Mac-E1008331FDC96864, BIOS 1715.81.2.0.0 (iBridge: 19.16.10744.0.0,0) 01/06/2022 Feb 12 11:01:52 MacBook kernel: Workqueue: efi_rts_wq efi_call_rts Feb 12 11:01:52 MacBook kernel: RIP: 0010:efi_crash_gracefully_on_page_fault+0x50/0xf0 Feb 12 11:01:52 MacBook kernel: Code: fc e8 44 30 03 00 49 81 fc ff 0f 00 00 76 08 48 3d 50 04 3c 9b 74 04 41 5c 5d c3 4c 89 e6 48 c7 c7 c0 00 7c 9a e8 69 71 be 00 <0f> 0b 83 3d 87 62 11 02 0a 0f 84 0a 62 be 00 e8 bc 1b 00 00 48 8b Feb 12 11:01:52 MacBook kernel: RSP: 0000:ffffbc34c03f29d8 EFLAGS: 00010086 Feb 12 11:01:52 MacBook kernel: RAX: 0000000000000000 RBX: ffffbc34c03f2a18 RCX: 0000000000000000 Feb 12 11:01:52 MacBook kernel: RDX: 0000000000000003 RSI: ffffbc34c03f2820 RDI: 00000000ffffffff Feb 12 11:01:52 MacBook kernel: RBP: ffffbc34c03f29e0 R08: 0000000000000003 R09: 0000000000000001 Feb 12 11:01:52 MacBook kernel: R10: ffff9f6801685640 R11: 0000000000000001 R12: ffffbc34c0068000 Feb 12 11:01:52 MacBook kernel: R13: 0000000000000000 R14: ffffbc34c03f2b68 R15: ffff9f6801233380 Feb 12 11:01:52 MacBook kernel: FS: 0000000000000000(0000) GS:ffff9f6b6ebc0000(0000) knlGS:0000000000000000 Feb 12 11:01:52 MacBook kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Feb 12 11:01:52 MacBook kernel: CR2: ffffbc34c0068000 CR3: 00000001001ec002 CR4: 00000000003706e0 Feb 12 11:01:52 MacBook kernel: Call Trace: Feb 12 11:01:52 MacBook kernel: <TASK> Feb 12 11:01:52 MacBook kernel: page_fault_oops+0x4f/0x2c0 Feb 12 11:01:52 MacBook kernel: ? search_bpf_extables+0x6b/0x80 Feb 12 11:01:52 MacBook kernel: ? search_module_extables+0x50/0x80 Feb 12 11:01:52 MacBook kernel: ? search_exception_tables+0x5b/0x60 Feb 12 11:01:52 MacBook kernel: kernelmode_fixup_or_oops+0x9e/0x110 Feb 12 11:01:52 MacBook kernel: __bad_area_nosemaphore+0x155/0x190 Feb 12 11:01:52 MacBook kernel: bad_area_nosemaphore+0x16/0x20 Feb 12 11:01:52 MacBook kernel: do_kern_addr_fault+0x8c/0xa0 Feb 12 11:01:52 MacBook kernel: exc_page_fault+0xd8/0x180 Feb 12 11:01:52 MacBook kernel: asm_exc_page_fault+0x1e/0x30 Feb 12 11:01:52 MacBook kernel: RIP: 0010:0xfffffffeefc440c5 Feb 12 11:01:52 MacBook kernel: Code: 31 c9 48 29 f9 48 83 e1 0f 74 0c 4c 39 c1 49 0f 47 c8 49 29 c8 f3 a4 4c 89 c1 49 83 e0 0f 48 c1 e9 04 74 2c f3 0f 7f 44 24 18 <f3> 0f 6f 06 66 0f e7 07 48 83 c6 10 48 83 c7 10 e2 ee 0f ae f0 66 Feb 12 11:01:52 MacBook kernel: RSP: 0000:ffffbc34c03f2c18 EFLAGS: 00010286 Feb 12 11:01:52 MacBook kernel: RAX: fffffffeefc9205a RBX: ffffffff9a81787a RCX: 0000000000000033 Feb 12 11:01:52 MacBook kernel: RDX: ffffbc34c0067d20 RSI: ffffbc34c0067ff6 RDI: fffffffeefc92330 Feb 12 11:01:52 MacBook kernel: RBP: ffffbc34c03f2ca0 R08: 0000000000000001 R09: ffffbc34c0068326 Feb 12 11:01:52 MacBook kernel: R10: fffffffeefc8e018 R11: 000000000019f2a5 R12: 0000000000000000 Feb 12 11:01:52 MacBook kernel: R13: ffffbc34c0067db0 R14: ffffbc34c0067d01 R15: 0000000000000607 Feb 12 11:01:52 MacBook kernel: ? __efi_call+0x28/0x30 Feb 12 11:01:52 MacBook kernel: ? switch_mm+0x20/0x30 Feb 12 11:01:52 MacBook kernel: ? efi_call_rts+0x20d/0x970 Feb 12 11:01:52 MacBook kernel: ? process_one_work+0x222/0x3f0 Feb 12 11:01:52 MacBook kernel: ? worker_thread+0x4a/0x3d0 Feb 12 11:01:52 MacBook kernel: ? kthread+0x17a/0x1a0 Feb 12 11:01:52 MacBook kernel: ? process_one_work+0x3f0/0x3f0 Feb 12 11:01:52 MacBook kernel: ? set_kthread_struct+0x40/0x40 Feb 12 11:01:52 MacBook kernel: ? ret_from_fork+0x22/0x30 Feb 12 11:01:52 MacBook kernel: </TASK> Feb 12 11:01:52 MacBook kernel: ---[ end trace c81d89c8fdfe87c4 ]--- Feb 12 11:01:52 MacBook kernel: efi: Froze efi_rts_wq and disabled EFI Runtime Services Feb 12 11:01:52 MacBook kernel: integrity: Couldn't get size: 0x8000000000000015 Feb 12 11:01:52 MacBook kernel: integrity: MODSIGN: Couldn't get UEFI db list Feb 12 11:01:52 MacBook kernel: efi: EFI Runtime Services are disabled! Feb 12 11:01:52 MacBook kernel: integrity: Couldn't get size: 0x8000000000000015 Feb 12 11:01:52 MacBook kernel: integrity: Couldn't get UEFI dbx list Feb 12 11:01:52 MacBook kernel: integrity: Couldn't get size: 0x8000000000000015 Feb 12 11:01:52 MacBook kernel: integrity: Couldn't get mokx list Feb 12 11:01:52 MacBook kernel: integrity: Couldn't get size: 0x8000000000000015 Feb 12 11:01:52 MacBook kernel: integrity: Couldn't get UEFI MokListRT The full journalctl log is here on https://gist.githubusercontent.com/AdityaGarg8/8e820c2724a65fb4bbb5deae2b358dc8/raw/c71e13036426211cbd590fdfabe5f88531bac645/log.log With CONFIG_LOAD_UEFI_KEYS=n, these variables are not seen and EFI Runtime Services work.
On Sat, Feb 12, 2022 at 05:53:47AM +0000, Aditya Garg wrote:
> Feb 12 11:01:52 MacBook kernel: Reading EFI variable db-d719b2cb-3d3a-4596-a3bc-dad00e67656f
Ok. With CONFIG_LOAD_UEFI_KEYS=n, can you run:
cat /sys/firmware/efi/efivars/db-d719b2cb-3d3a-4596-a3bc-dad00e67656f
and see whether it generates the same failure? If so then my (handwavy)
guess is that something's going wrong with a firmware codepath for the
d719b2cb-3d3a-4596-a3bc-dad00e67656f GUID. Someone could potentially
then figure out whether the same happens under Windows, but the easiest
thing is probably to just return a failure on Apple hardware when
someone tries to access anything with that GUID.
> > Ok. With CONFIG_LOAD_UEFI_KEYS=n, can you run: > > cat /sys/firmware/efi/efivars/db-d719b2cb-3d3a-4596-a3bc-dad00e67656f > > and see whether it generates the same failure? If so then my (handwavy) > guess is that something's going wrong with a firmware codepath for the > d719b2cb-3d3a-4596-a3bc-dad00e67656f GUID. Someone could potentially > then figure out whether the same happens under Windows, but the easiest > thing is probably to just return a failure on Apple hardware when > someone tries to access anything with that GUID. Surprisingly it didn’t cause a crash. The logs are at https://gist.githubusercontent.com/AdityaGarg8/8e820c2724a65fb4bbb5deae2b358dc8/raw/2a003ef43ae06dbe2bcc22b34ba7ccbb03898a21/log2.log I also tried cat /sys/firmware/efi/efivars/MokIgnoreDB-605dab50-e046-4300-abb6-3dd810dd8b23, but it doesn’t exist aditya@MacBook:~$ cat /sys/firmware/efi/efivars/MokIgnoreDB-605dab50-e046-4300-abb6-3dd810dd8b23 cat: /sys/firmware/efi/efivars/MokIgnoreDB-605dab50-e046-4300-abb6-3dd810dd8b23: No such file or directory
On Sun, Feb 13, 2022 at 08:22:32AM +0000, Aditya Garg wrote:
> Surprisingly it didn’t cause a crash. The logs are at https://gist.githubusercontent.com/AdityaGarg8/8e820c2724a65fb4bbb5deae2b358dc8/raw/2a003ef43ae06dbe2bcc22b34ba7ccbb03898a21/log2.log
Interesting. Ok, so there's something else going on here. I'll have
access to a T2 system next week, so I'll take a look then. Is this
something that started happening recently, or has it always happened if
this config option is set on these platforms?
> > Interesting. Ok, so there's something else going on here. I'll have > access to a T2 system next week, so I'll take a look then. Is this > something that started happening recently, or has it always happened if > this config option is set on these platforms? Before https://github.com/torvalds/linux/commit/f5390cd0b43c2e54c7cf5506c7da4a37c5cef746, we had to add efi=noruntime to get Linux working on these machines. Now, its this config option only which is the issue. You may want to follow https://wiki.t2linux.org/ to test on a T2 Mac, since many T2 patches haven't been upstreamed yet.
diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c index 08b6d12f9..668b2a713 100644 --- a/security/integrity/platform_certs/load_uefi.c +++ b/security/integrity/platform_certs/load_uefi.c @@ -3,6 +3,7 @@ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/cred.h> +#include <linux/dmi.h> #include <linux/err.h> #include <linux/efi.h> #include <linux/slab.h> @@ -12,6 +13,106 @@ #include "../integrity.h" #include "keyring_handler.h" +/* Apple Macs with T2 Security chip don't support these UEFI variables. + * The T2 chip manages the Secure Boot and does not allow Linux to boot + * if it is turned on. If turned off, an attempt to get certificates + * causes a crash, so we simply return 0 for them in each function. + */ + +static const struct dmi_system_id uefi_apple_ignore[] = { + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,1"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,2"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,3"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro15,4"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,1"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,2"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,3"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro16,4"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir8,1"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir8,2"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookAir9,1"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacMini8,1"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacPro7,1"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "iMac20,1"), + }, + }, + { + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "iMac20,2"), + }, + }, + { } +}; + /* * Look to see if a UEFI variable called MokIgnoreDB exists and return true if * it does. @@ -21,12 +122,18 @@ * is set, we should ignore the db variable also and the true return indicates * this. */ + static __init bool uefi_check_ignore_db(void) { efi_status_t status; unsigned int db = 0; unsigned long size = sizeof(db); efi_guid_t guid = EFI_SHIM_LOCK_GUID; + const struct dmi_system_id *dmi_id; + + dmi_id = dmi_first_match(uefi_apple_ignore); + if (dmi_id) + return 0; status = efi.get_variable(L"MokIgnoreDB", &guid, NULL, &size, &db); return status == EFI_SUCCESS; @@ -41,6 +148,11 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid, unsigned long lsize = 4; unsigned long tmpdb[4]; void *db; + const struct dmi_system_id *dmi_id; + + dmi_id = dmi_first_match(uefi_apple_ignore); + if (dmi_id) + return 0; *status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb); if (*status == EFI_NOT_FOUND) @@ -85,6 +197,11 @@ static int __init load_moklist_certs(void) unsigned long moksize; efi_status_t status; int rc; + const struct dmi_system_id *dmi_id; + + dmi_id = dmi_first_match(uefi_apple_ignore); + if (dmi_id) + return 0; /* First try to load certs from the EFI MOKvar config table. * It's not an error if the MOKvar config table doesn't exist @@ -138,6 +255,11 @@ static int __init load_uefi_certs(void) unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0; efi_status_t status; int rc = 0; + const struct dmi_system_id *dmi_id; + + dmi_id = dmi_first_match(uefi_apple_ignore); + if (dmi_id) + return 0; if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE)) return false;