[v10,12/15] platform/x86: dell-smbios: Add filtering support

Message ID	2dfbb122aa11fa9ff73cbfc6a403b82d1bb2e7c8.1508434514.git.mario.limonciello@dell.com (mailing list archive)
State	Superseded, archived
Delegated to:	Darren Hart
Headers	show Return-Path: <platform-driver-x86-owner@kernel.org> From: Mario Limonciello <mario.limonciello@dell.com> To: dvhart@infradead.org, Andy Shevchenko <andy.shevchenko@gmail.com> Cc: LKML <linux-kernel@vger.kernel.org>, platform-driver-x86@vger.kernel.org, Andy Lutomirski <luto@kernel.org>, quasisec@google.com, pali.rohar@gmail.com, rjw@rjwysocki.net, mjg59@google.com, hch@lst.de, Greg KH <greg@kroah.com>, Alan Cox <gnomes@lxorguk.ukuu.org.uk>, Mario Limonciello <mario.limonciello@dell.com> Subject: [PATCH v10 12/15] platform/x86: dell-smbios: Add filtering support Date: Thu, 19 Oct 2017 12:50:15 -0500 Message-Id: <2dfbb122aa11fa9ff73cbfc6a403b82d1bb2e7c8.1508434514.git.mario.limonciello@dell.com> In-Reply-To: <cover.1508434513.git.mario.limonciello@dell.com> References: <cover.1508434513.git.mario.limonciello@dell.com> In-Reply-To: <cover.1508434513.git.mario.limonciello@dell.com> References: <cover.1508434513.git.mario.limonciello@dell.com> Sender: platform-driver-x86-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/platform/x86/dell-smbios.c b/drivers/platform/x86/dell-smbios.c index b540cd4605f7..b2aeb740c04b 100644 --- a/drivers/platform/x86/dell-smbios.c +++ b/drivers/platform/x86/dell-smbios.c @@ -24,6 +24,7 @@ #include <linux/slab.h> #include "dell-smbios.h" +static u32 da_supported_commands; static int da_num_tokens; static struct platform_device *platform_device; static struct calling_interface_token *da_tokens; @@ -38,6 +39,91 @@ struct smbios_device { int (*call_fn)(struct calling_interface_buffer *); }; +struct smbios_call { + u32 need_capability; + int class; + int select; +}; + +/* calls that are whitelisted for given capabilities */ +static struct smbios_call call_whitelist[] = { + /* generally tokens are allowed, but may be further filtered or + * restricted by token blacklist or whitelist + */ + {CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_STD}, + {CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_AC}, + {CAP_SYS_ADMIN, CLASS_TOKEN_READ, SELECT_TOKEN_BAT}, + {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_STD}, + {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_AC}, + {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE, SELECT_TOKEN_BAT}, + /* used by userspace: fwupdate */ + {CAP_SYS_ADMIN, CLASS_ADMIN_PROP, SELECT_ADMIN_PROP}, + /* used by userspace: fwupd */ + {CAP_SYS_ADMIN, CLASS_INFO, SELECT_DOCK}, + {CAP_SYS_ADMIN, CLASS_FLASH_INTERFACE, SELECT_FLASH_INTERFACE}, +}; + +/* calls that are explicitly blacklisted */ +static struct smbios_call call_blacklist[] = { + {0x0000, 01, 07}, /* manufacturing use */ + {0x0000, 06, 05}, /* manufacturing use */ + {0x0000, 11, 03}, /* write once */ + {0x0000, 11, 07}, /* write once */ + {0x0000, 11, 11}, /* write once */ + {0x0000, 19, -1}, /* diagnostics */ + /* handled by kernel: dell-laptop */ + {0x0000, CLASS_INFO, SELECT_RFKILL}, + {0x0000, CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT}, +}; + +struct token_range { + u32 need_capability; + u16 min; + u16 max; +}; + +/* tokens that are whitelisted for given capabilities */ +static struct token_range token_whitelist[] = { + /* used by userspace: fwupdate */ + {CAP_SYS_ADMIN, CAPSULE_EN_TOKEN, CAPSULE_DIS_TOKEN}, + /* can indicate to userspace that WMI is needed */ + {0x0000, WSMT_EN_TOKEN, WSMT_DIS_TOKEN} +}; + +/* tokens that are explicitly blacklisted */ +static struct token_range token_blacklist[] = { + {0x0000, 0x0058, 0x0059}, /* ME use */ + {0x0000, 0x00CD, 0x00D0}, /* raid shadow copy */ + {0x0000, 0x013A, 0x01FF}, /* sata shadow copy */ + {0x0000, 0x0175, 0x0176}, /* write once */ + {0x0000, 0x0195, 0x0197}, /* diagnostics */ + {0x0000, 0x01DC, 0x01DD}, /* manufacturing use */ + {0x0000, 0x027D, 0x0284}, /* diagnostics */ + {0x0000, 0x02E3, 0x02E3}, /* manufacturing use */ + {0x0000, 0x02FF, 0x02FF}, /* manufacturing use */ + {0x0000, 0x0300, 0x0302}, /* manufacturing use */ + {0x0000, 0x0325, 0x0326}, /* manufacturing use */ + {0x0000, 0x0332, 0x0335}, /* fan control */ + {0x0000, 0x0350, 0x0350}, /* manufacturing use */ + {0x0000, 0x0363, 0x0363}, /* manufacturing use */ + {0x0000, 0x0368, 0x0368}, /* manufacturing use */ + {0x0000, 0x03F6, 0x03F7}, /* manufacturing use */ + {0x0000, 0x049E, 0x049F}, /* manufacturing use */ + {0x0000, 0x04A0, 0x04A3}, /* disagnostics */ + {0x0000, 0x04E6, 0x04E7}, /* manufacturing use */ + {0x0000, 0x4000, 0x7FFF}, /* internal BIOS use */ + {0x0000, 0x9000, 0x9001}, /* internal BIOS use */ + {0x0000, 0xA000, 0xBFFF}, /* write only */ + {0x0000, 0xEFF0, 0xEFFF}, /* internal BIOS use */ + /* handled by kernel: dell-laptop */ + {0x0000, BRIGHTNESS_TOKEN, BRIGHTNESS_TOKEN}, + {0x0000, KBD_LED_OFF_TOKEN, KBD_LED_AUTO_TOKEN}, + {0x0000, KBD_LED_AC_TOKEN, KBD_LED_AC_TOKEN}, + {0x0000, KBD_LED_AUTO_25_TOKEN, KBD_LED_AUTO_75_TOKEN}, + {0x0000, KBD_LED_AUTO_100_TOKEN, KBD_LED_AUTO_100_TOKEN}, + {0x0000, GLOBAL_MIC_MUTE_ENABLE, GLOBAL_MIC_MUTE_DISABLE}, +}; + static LIST_HEAD(smbios_device_list); int dell_smbios_error(int value) @@ -90,6 +176,108 @@ void dell_smbios_unregister_device(struct device *d) } EXPORT_SYMBOL_GPL(dell_smbios_unregister_device); +int dell_smbios_call_filter(struct device *d, + struct calling_interface_buffer *buffer) +{ + u16 t = 0; + int i; + + /* can't make calls over 30 */ + if (buffer->class > 30) { + dev_dbg(d, "class too big: %u\n", buffer->class); + return -EINVAL; + } + + /* supported calls on the particular system */ + if (!(da_supported_commands & (1 << buffer->class))) { + dev_dbg(d, "invalid command, supported commands: 0x%8x\n", + da_supported_commands); + return -EINVAL; + } + + /* match against call blacklist */ + for (i = 0; i < ARRAY_SIZE(call_blacklist); i++) { + if (buffer->class != call_blacklist[i].class) + continue; + if (buffer->select != call_blacklist[i].select && + call_blacklist[i].select != -1) + continue; + dev_dbg(d, "blacklisted command: %u/%u\n", + buffer->class, buffer->select); + return -EINVAL; + } + + /* if a token call, find token ID */ + if ((buffer->class == CLASS_TOKEN_READ && buffer->select < 3) || + (buffer->class == CLASS_TOKEN_WRITE && buffer->select < 3)) { + /* find the matching token ID */ + for (i = 0; i < da_num_tokens; i++) { + if (da_tokens[i].location != buffer->input[0]) + continue; + t = da_tokens[i].tokenID; + break; + } + + /* token call; but token didn't exist */ + if (!t) { + dev_dbg(d, "token at location %04x doesn't exist\n", + buffer->input[0]); + return -EINVAL; + } + + /* match against token blacklist */ + for (i = 0; i < ARRAY_SIZE(token_blacklist); i++) { + if (!token_blacklist[i].min || !token_blacklist[i].max) + continue; + if (t >= token_blacklist[i].min && + t <= token_blacklist[i].max) + return -EINVAL; + } + + /* match against token whitelist */ + for (i = 0; i < ARRAY_SIZE(token_whitelist); i++) { + if (!token_whitelist[i].min || !token_whitelist[i].max) + continue; + if (t < token_whitelist[i].min || + t > token_whitelist[i].max) + continue; + if (!token_whitelist[i].need_capability || + capable(token_whitelist[i].need_capability)) { + dev_dbg(d, "whitelisted token: %x\n", t); + return 0; + } + + } + } + /* match against call whitelist */ + for (i = 0; i < ARRAY_SIZE(call_whitelist); i++) { + if (buffer->class != call_whitelist[i].class) + continue; + if (buffer->select != call_whitelist[i].select) + continue; + if (!call_whitelist[i].need_capability || + capable(call_whitelist[i].need_capability)) { + dev_dbg(d, "whitelisted capable command: %u/%u\n", + buffer->class, buffer->select); + return 0; + } + dev_dbg(d, "missing capability %d for %u/%u\n", + call_whitelist[i].need_capability, + buffer->class, buffer->select); + + } + + /* not in a whitelist, only allow processes with capabilities */ + if (capable(CAP_SYS_RAWIO)) { + dev_dbg(d, "Allowing %u/%u due to CAP_SYS_RAWIO\n", + buffer->class, buffer->select); + return 0; + } + + return -EACCES; +} +EXPORT_SYMBOL_GPL(dell_smbios_call_filter); + int dell_smbios_call(struct calling_interface_buffer *buffer) { int (*call_fn)(struct calling_interface_buffer *) = NULL; @@ -168,6 +356,8 @@ static void __init parse_da_table(const struct dmi_header *dm) if (dm->length < 17) return; + da_supported_commands = table->supportedCmds; + new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) * sizeof(struct calling_interface_token), GFP_KERNEL); diff --git a/drivers/platform/x86/dell-smbios.h b/drivers/platform/x86/dell-smbios.h index 956fe9304ed7..23256f79a4b8 100644 --- a/drivers/platform/x86/dell-smbios.h +++ b/drivers/platform/x86/dell-smbios.h @@ -26,9 +26,14 @@ #define SELECT_TOKEN_AC 2 #define CLASS_KBD_BACKLIGHT 4 #define SELECT_KBD_BACKLIGHT 11 +#define CLASS_FLASH_INTERFACE 7 +#define SELECT_FLASH_INTERFACE 3 +#define CLASS_ADMIN_PROP 10 +#define SELECT_ADMIN_PROP 3 #define CLASS_INFO 17 #define SELECT_RFKILL 11 #define SELECT_APP_REGISTRATION 3 +#define SELECT_DOCK 22 /* Tokens used in kernel drivers, any of these * should be filtered from userspace access @@ -44,6 +49,10 @@ #define KBD_LED_AUTO_100_TOKEN 0x02F6 #define GLOBAL_MIC_MUTE_ENABLE 0x0364 #define GLOBAL_MIC_MUTE_DISABLE 0x0365 + +/* tokens whitelisted to userspace use */ +#define CAPSULE_EN_TOKEN 0x0461 +#define CAPSULE_DIS_TOKEN 0x0462 #define WSMT_EN_TOKEN 0x04EC #define WSMT_DIS_TOKEN 0x04ED @@ -80,6 +89,8 @@ int dell_smbios_register_device(struct device *d, void *call_fn); void dell_smbios_unregister_device(struct device *d); int dell_smbios_error(int value); +int dell_smbios_call_filter(struct device *d, + struct calling_interface_buffer *buffer); int dell_smbios_call(struct calling_interface_buffer *buffer); struct calling_interface_token *dell_smbios_find_token(int tokenid);

[v10,12/15] platform/x86: dell-smbios: Add filtering support

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