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Fri, 15 Apr 2022 17:02:46 +0000 From: Aditya Garg To: "jarkko@kernel.org" , "zohar@linux.ibm.com" , "dmitry.kasatkin@gmail.com" , "jmorris@namei.org" , "serge@hallyn.com" , "ast@kernel.org" , "daniel@iogearbox.net" , "andrii@kernel.org" , "kafai@fb.com" , "songliubraving@fb.com" , "yhs@fb.com" , "john.fastabend@gmail.com" , "kpsingh@kernel.org" CC: "linux-integrity@vger.kernel.org" , "keyrings@vger.kernel.org" , "linux-security-module@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" , "bpf@vger.kernel.org" , Orlando Chamberlain , "admin@kodeit.net" , "stable@vger.kernel.org" Subject: [PATCH v7] efi: Do not import certificates from UEFI Secure Boot for T2 Macs Thread-Topic: [PATCH v7] efi: Do not import certificates from UEFI Secure Boot for T2 Macs Thread-Index: AQHYUOqhkcZ1390yh0eyOvPJZusvzg== Date: Fri, 15 Apr 2022 17:02:46 +0000 Message-ID: <958B8D22-F11E-4B5D-9F44-6F0626DBCB63@live.com> References: <652C3E9E-CB97-4C70-A961-74AF8AEF9E39@live.com> <94DD0D83-8FDE-4A61-AAF0-09A0175A0D0D@live.com> <590ED76A-EE91-4ED1-B524-BC23419C051E@live.com> <02125722-91FC-43D3-B63C-1B789C2DA8C3@live.com> In-Reply-To: <02125722-91FC-43D3-B63C-1B789C2DA8C3@live.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-tmn: [bQR+8ou+FdCN2ZYuxbZ6XBTpy89aIxWw4iWsDekM7fJhY4Bt6P3imwm7h67S/osJSXE6YlpYLcg=] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 60399964-4885-4391-1c5f-08da1f01c3de x-ms-traffictypediagnostic: BM1PR01MB2881:EE_ x-microsoft-antispam: BCL:0; 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Cc: stable@vger.kernel.org Signed-off-by: Aditya Garg Reviewed-by: Mimi Zohar --- v2 :- Reduce code size of the table. v3 :- Close the brackets which were left open by mistake. v4 :- Fix comment style issues, remove blank spaces and limit use of dmi_first_match() v4 RESEND :- Add stable to cc v5 :- Rewrite the description v6 :- Make description more clear v7 :- Minor changes and add reviewed by .../platform_certs/keyring_handler.h | 8 +++++ security/integrity/platform_certs/load_uefi.c | 33 +++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h index 284558f30..212d894a8 100644 --- a/security/integrity/platform_certs/keyring_handler.h +++ b/security/integrity/platform_certs/keyring_handler.h @@ -35,3 +35,11 @@ efi_element_handler_t get_handler_for_mok(const efi_guid_t *sig_type); efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type); #endif + +#ifndef UEFI_QUIRK_SKIP_CERT +#define UEFI_QUIRK_SKIP_CERT(vendor, product) \ + .matches = { \ + DMI_MATCH(DMI_BOARD_VENDOR, vendor), \ + DMI_MATCH(DMI_PRODUCT_NAME, product), \ + }, +#endif diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c index 5f45c3c07..1a7e7d597 100644 --- a/security/integrity/platform_certs/load_uefi.c +++ b/security/integrity/platform_certs/load_uefi.c @@ -3,6 +3,7 @@ #include #include #include +#include #include #include #include @@ -12,6 +13,31 @@ #include "../integrity.h" #include "keyring_handler.h" +/* + * On T2 Macs reading the db and dbx efi variables to load UEFI Secure Boot + * certificates causes occurrence of a page fault in Apple's firmware and + * a crash disabling EFI runtime services. The following quirk skips reading + * these variables. + */ +static const struct dmi_system_id uefi_skip_cert[] = { + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,2") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,3") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,4") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,2") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,3") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,4") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,2") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir9,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacMini8,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacPro7,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,2") }, + { } +}; + /* * Look to see if a UEFI variable called MokIgnoreDB exists and return true if * it does. @@ -138,6 +164,13 @@ 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_skip_cert); + if (dmi_id) { + pr_err("Reading UEFI Secure Boot Certs is not supported on T2 Macs.\n"); + return false; + } if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE)) return false;