diff options
| author | Patrick Rudolph <patrick.rudolph@9elements.com> | 2020-05-06 11:58:45 +0200 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2020-08-21 07:51:07 +0000 |
| commit | 9f8f11513a5db45b224f764525eae9c64fcfe360 (patch) | |
| tree | be1b5a603cc8d19e96ef0bf31037e9975c6a6c8b /src/soc/intel/broadwell | |
| parent | 37ac368c780568628e45c6fa93aaa55a2030c06b (diff) | |
SMM: Validate more user-provided pointers
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>
Diffstat (limited to 'src/soc/intel/broadwell')
| -rw-r--r-- | src/soc/intel/broadwell/smihandler.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/soc/intel/broadwell/smihandler.c b/src/soc/intel/broadwell/smihandler.c index 86be400e71..8dbb40f2b7 100644 --- a/src/soc/intel/broadwell/smihandler.c +++ b/src/soc/intel/broadwell/smihandler.c @@ -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); } |