From 9ef82e29478c76f17b536f8f289fd0406067ab01 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Wed, 25 Aug 2021 19:13:24 +0200 Subject: efi_loader: don't load signature database from file The UEFI specification requires that the signature database may only be stored in tamper-resistant storage. So these variable may not be read from an unsigned file. Signed-off-by: Heinrich Schuchardt --- lib/efi_loader/efi_var_file.c | 41 +++++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 16 deletions(-) (limited to 'lib/efi_loader/efi_var_file.c') diff --git a/lib/efi_loader/efi_var_file.c b/lib/efi_loader/efi_var_file.c index de076b8cbc..c7c6805ed0 100644 --- a/lib/efi_loader/efi_var_file.c +++ b/lib/efi_loader/efi_var_file.c @@ -148,9 +148,10 @@ error: #endif } -efi_status_t efi_var_restore(struct efi_var_file *buf) +efi_status_t efi_var_restore(struct efi_var_file *buf, bool safe) { struct efi_var_entry *var, *last_var; + u16 *data; efi_status_t ret; if (buf->reserved || buf->magic != EFI_VAR_FILE_MAGIC || @@ -160,21 +161,29 @@ efi_status_t efi_var_restore(struct efi_var_file *buf) return EFI_INVALID_PARAMETER; } - var = buf->var; last_var = (struct efi_var_entry *)((u8 *)buf + buf->length); - while (var < last_var) { - u16 *data = var->name + u16_strlen(var->name) + 1; - - if (var->attr & EFI_VARIABLE_NON_VOLATILE && var->length) { - ret = efi_var_mem_ins(var->name, &var->guid, var->attr, - var->length, data, 0, NULL, - var->time); - if (ret != EFI_SUCCESS) - log_err("Failed to set EFI variable %ls\n", - var->name); - } - var = (struct efi_var_entry *) - ALIGN((uintptr_t)data + var->length, 8); + for (var = buf->var; var < last_var; + var = (struct efi_var_entry *) + ALIGN((uintptr_t)data + var->length, 8)) { + + data = var->name + u16_strlen(var->name) + 1; + + /* + * Secure boot related and non-volatile variables shall only be + * restored from U-Boot's preseed. + */ + if (!safe && + (efi_auth_var_get_type(var->name, &var->guid) != + EFI_AUTH_VAR_NONE || + !(var->attr & EFI_VARIABLE_NON_VOLATILE))) + continue; + if (!var->length) + continue; + ret = efi_var_mem_ins(var->name, &var->guid, var->attr, + var->length, data, 0, NULL, + var->time); + if (ret != EFI_SUCCESS) + log_err("Failed to set EFI variable %ls\n", var->name); } return EFI_SUCCESS; } @@ -213,7 +222,7 @@ efi_status_t efi_var_from_file(void) log_err("Failed to load EFI variables\n"); goto error; } - if (buf->length != len || efi_var_restore(buf) != EFI_SUCCESS) + if (buf->length != len || efi_var_restore(buf, false) != EFI_SUCCESS) log_err("Invalid EFI variables file\n"); error: free(buf); -- cgit v1.2.3