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SMM: Validate more user-provided pointers

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Mitigate issues presented in "Digging Into The Core of Boot" found by
"Yuriy Bulygin" and "Oleksandr Bazhaniuk" at RECON-MTL-2017.

Validate user-provided pointers using the newly-added functions.
This protects SMM from ring0 attacks.

Change-Id: I8a347ccdd20816924bf1bceb3b24bf7b22309312
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Christian Walter <christian.walter@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41086
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
This commit is contained in:
Patrick Rudolph
2020-05-06 11:58:45 +02:00
committed by Patrick Georgi
parent 37ac368c78
commit 9f8f11513a
8 changed files with 58 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
src/mainboard/lenovo/t60/smihandler.c
View File

@ -2,6 +2,7 @@
#include <arch/io.h>
#include <device/pci_ops.h>
#include <device/pci_def.h>
#include <console/console.h>
#include <cpu/x86/smm.h>
#include <southbridge/intel/i82801gx/nvs.h>
@ -16,25 +17,33 @@
static void mainboard_smi_brightness_down(void)
{
u8 *bar;
if ((bar = (u8 *)pci_read_config32(PCI_DEV(1, 0, 0), 0x18))) {
printk(BIOS_DEBUG, "bar: %08X, level %02X\n", (unsigned int)bar, *(bar+LVTMA_BL_MOD_LEVEL));
uint32_t reg32 = pci_read_config32(PCI_DEV(1, 0, 0), PCI_BASE_ADDRESS_2) & ~0xf;
u8 *bar = (void *)(uintptr_t)reg32;
/* Validate pointer before using it */
if (!bar || smm_points_to_smram(bar, LVTMA_BL_MOD_LEVEL + sizeof(uint8_t)))
return;
printk(BIOS_DEBUG, "bar: %p, level %02X\n", bar, *(bar+LVTMA_BL_MOD_LEVEL));
*(bar+LVTMA_BL_MOD_LEVEL) &= 0xf0;
if (*(bar+LVTMA_BL_MOD_LEVEL) > 0x10)
*(bar+LVTMA_BL_MOD_LEVEL) -= 0x10;
}
}
static void mainboard_smi_brightness_up(void)
{
u8 *bar;
if ((bar = (u8 *)pci_read_config32(PCI_DEV(1, 0, 0), 0x18))) {
printk(BIOS_DEBUG, "bar: %08X, level %02X\n", (unsigned int)bar, *(bar+LVTMA_BL_MOD_LEVEL));
uint32_t reg32 = pci_read_config32(PCI_DEV(1, 0, 0), PCI_BASE_ADDRESS_2) & ~0xf;
u8 *bar = (void *)(uintptr_t)reg32;
/* Validate pointer before using it */
if (!bar || smm_points_to_smram(bar, LVTMA_BL_MOD_LEVEL + sizeof(uint8_t)))
return;
printk(BIOS_DEBUG, "bar: %p, level %02X\n", bar, *(bar+LVTMA_BL_MOD_LEVEL));
*(bar+LVTMA_BL_MOD_LEVEL) |= 0x0f;
if (*(bar+LVTMA_BL_MOD_LEVEL) < 0xf0)
*(bar+LVTMA_BL_MOD_LEVEL) += 0x10;
}
}
int mainboard_io_trap_handler(int smif)
{

4
src/soc/intel/baytrail/smihandler.c
View File

@ -321,6 +321,10 @@ static void southbridge_smi_apmc(void)
if (state) {
/* EBX in the state save contains the GNVS pointer */
gnvs = (struct global_nvs *)((uint32_t)state->rbx);
if (smm_points_to_smram(gnvs, sizeof(*gnvs))) {
printk(BIOS_ERR, "SMI#: ERROR: GNVS overlaps SMM\n");
return;
}
smm_initialized = 1;
printk(BIOS_DEBUG, "SMI#: Setting GNVS to %p\n", gnvs);
}

4
src/soc/intel/braswell/smihandler.c
View File

@ -301,6 +301,10 @@ static void southbridge_smi_apmc(void)
if (state) {
/* EBX in the state save contains the GNVS pointer */
gnvs = (struct global_nvs *)((uint32_t)state->rbx);
if (smm_points_to_smram(gnvs, sizeof(*gnvs))) {
printk(BIOS_ERR, "SMI#: ERROR: GNVS overlaps SMM\n");
return;
}
smm_initialized = 1;
printk(BIOS_DEBUG, "SMI#: Setting GNVS to %p\n", gnvs);
}

8
src/soc/intel/broadwell/smihandler.c
View File

@ -100,6 +100,10 @@ static void backlight_off(void)
reg_base = (void *)((uintptr_t)pci_read_config32(SA_DEV_IGD,
PCI_BASE_ADDRESS_0) & ~0xf);
/* Validate pointer before using it */
if (smm_points_to_smram(reg_base, PCH_PP_OFF_DELAYS + sizeof(uint32_t)))
return;
/* Check if backlight is enabled */
pp_ctrl = read32(reg_base + PCH_PP_CONTROL);
if (!(pp_ctrl & EDP_BLC_ENABLE))
@ -341,6 +345,10 @@ static void southbridge_smi_apmc(void)
if (state) {
/* EBX in the state save contains the GNVS pointer */
gnvs = (struct global_nvs *)((u32)state->rbx);
if (smm_points_to_smram(gnvs, sizeof(*gnvs))) {
printk(BIOS_ERR, "SMI#: ERROR: GNVS overlaps SMM\n");
return;
}
smm_initialized = 1;
printk(BIOS_DEBUG, "SMI#: Setting GNVS to %p\n", gnvs);
}

4
src/soc/intel/common/block/smm/smihandler.c
View File

@ -373,6 +373,10 @@ void smihandler_southbridge_apmc(
/* EBX in the state save contains the GNVS pointer */
uint32_t reg_ebx = save_state_ops->get_reg(state, RBX);
gnvs = (struct global_nvs *)(uintptr_t)reg_ebx;
if (smm_points_to_smram(gnvs, sizeof(*gnvs))) {
printk(BIOS_ERR, "SMI#: ERROR: GNVS overlaps SMM\n");
return;
}
smm_initialized = 1;
printk(BIOS_DEBUG, "SMI#: Setting GNVS to %p\n", gnvs);
}

7
src/southbridge/intel/bd82x6x/smihandler.c
View File

@ -4,6 +4,7 @@
#include <arch/io.h>
#include <device/pci_ops.h>
#include <console/console.h>
#include <commonlib/region.h>
#include <device/pci_def.h>
#include <cpu/x86/smm.h>
#include <cpu/intel/em64t101_save_state.h>
@ -103,6 +104,7 @@ static void xhci_sleep(u8 slp_typ)
xhci_bar = pci_read_config32(PCH_XHCI_DEV, PCI_BASE_ADDRESS_0) & ~0xFUL;
/* FIXME: This looks broken (conditions are always false) */
if ((xhci_bar + 0x4C0) & 1)
pch_iobp_update(0xEC000082, ~0UL, (3 << 2));
if ((xhci_bar + 0x4D0) & 1)
@ -191,6 +193,11 @@ void southbridge_update_gnvs(u8 apm_cnt, int *smm_done)
if (state) {
/* EBX in the state save contains the GNVS pointer */
gnvs = (struct global_nvs *)((u32)state->rbx);
struct region r = {(uintptr_t)gnvs, sizeof(struct global_nvs)};
if (smm_region_overlaps_handler(&r)) {
printk(BIOS_ERR, "SMI#: ERROR: GNVS overlaps SMM\n");
return;
}
*smm_done = 1;
printk(BIOS_DEBUG, "SMI#: Setting GNVS to %p\n", gnvs);
}

4
src/southbridge/intel/ibexpeak/smihandler.c
View File

@ -152,6 +152,10 @@ void southbridge_update_gnvs(u8 apm_cnt, int *smm_done)
if (state) {
/* EBX in the state save contains the GNVS pointer */
gnvs = (struct global_nvs *)((u32)state->rbx);
if (smm_points_to_smram(gnvs, sizeof(*gnvs))) {
printk(BIOS_ERR, "SMI#: ERROR: GNVS overlaps SMM\n");
return;
}
*smm_done = 1;
printk(BIOS_DEBUG, "SMI#: Setting GNVS to %p\n", gnvs);
}

4
src/southbridge/intel/lynxpoint/smihandler.c
View File

@ -314,6 +314,10 @@ static void southbridge_smi_apmc(void)
if (state) {
/* EBX in the state save contains the GNVS pointer */
gnvs = (struct global_nvs *)((u32)state->rbx);
if (smm_points_to_smram(gnvs, sizeof(*gnvs))) {
printk(BIOS_ERR, "SMI#: ERROR: GNVS overlaps SMM\n");
return;
}
smm_initialized = 1;
printk(BIOS_DEBUG, "SMI#: Setting GNVS to %p\n", gnvs);
}