Re: [PATCH 1/1] efi_loader: improve error handling in try_load_entry()

Hi Heinrich,

On Sat, 20 Apr 2024 at 17:01, Heinrich Schuchardt heinrich.schuchardt@canonical.com wrote:

The image is not unloaded if a security violation occurs.

If efi_set_load_options() fails, we do not free the memory allocated for the optional data. We do not unload the image.

If a load option is not active, we use a random value from the stack to allocate memory for the optional data of the load option.

• Unload the image if a security violation occurs.
• Free load_options if efi_set_load_options() fails.
• Unload the image if efi_set_load_options() fails.
• Do not allocate load_options with a random size from the stack if the boot entry is not active.

Where is that happening? Don't we always init the size in efi_get_var() & efi_deserialize_load_option()_ which are called early? efi_get_var() especially sets size = 0 even on failures

Fixes: 53f6a5aa8626 ("efi_loader: Replace config option for initrd loading")

I think we also need a fix tag for 0ad64007feb93 as well?

Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com

lib/efi_loader/efi_bootmgr.c | 97 +++++++++---------- test/py/tests/test_efi_secboot/test_signed.py | 28 +++--- .../test_efi_secboot/test_signed_intca.py | 10 +- .../tests/test_efi_secboot/test_unsigned.py | 6 +- 4 files changed, 70 insertions(+), 71 deletions(-)

diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c index 4ac519228a6..ca2ebdaa32f 100644 --- a/lib/efi_loader/efi_bootmgr.c +++ b/lib/efi_loader/efi_bootmgr.c @@ -613,9 +613,12 @@ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle, void *load_option; efi_uintn_t size; efi_status_t ret;

•   u32 attributes;
  
  

•   efi_create_indexed_name(varname, sizeof(varname), "Boot", n);
  

•   *handle = NULL;
  

•   *load_options = NULL;
  
  

•   efi_create_indexed_name(varname, sizeof(varname), "Boot", n);
  

    load_option = efi_get_var(varname, &efi_global_variable_guid, &size);
    if (!load_option)
            return EFI_LOAD_ERROR;

@@ -626,55 +629,54 @@ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle, goto error; }

•   if (lo.attributes & LOAD_OPTION_ACTIVE) {
  

•           u32 attributes;
  

•           log_debug("trying to load \"%ls\" from %pD\n", lo.label,
  

•                     lo.file_path);
  

•           if (EFI_DP_TYPE(lo.file_path, MEDIA_DEVICE, FILE_PATH)) {
  

•                   /* file_path doesn't contain a device path */
  

•                   ret = try_load_from_short_path(lo.file_path, handle);
  

•           } else if (EFI_DP_TYPE(lo.file_path, MESSAGING_DEVICE, MSG_URI)) {
  

•                   if (IS_ENABLED(CONFIG_EFI_HTTP_BOOT))
  

•                           ret = try_load_from_uri_path(
  

•                                   (struct efi_device_path_uri *)lo.file_path,
  

•                                   lo.label, handle);
  

•                   else
  

•                           ret = EFI_LOAD_ERROR;
  

•           } else {
  

•                   ret = try_load_from_media(lo.file_path, handle);
  

•           }
  

•           if (ret != EFI_SUCCESS) {
  

•                   log_warning("Loading %ls '%ls' failed\n",
  

•                               varname, lo.label);
  

•                   goto error;
  

•           }
  

•   if (!(lo.attributes & LOAD_OPTION_ACTIVE)) {
  

•           ret = EFI_LOAD_ERROR;
  

•           goto error;
  

•   }
  
  

•           attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
  

•                        EFI_VARIABLE_RUNTIME_ACCESS;
  

•           ret = efi_set_variable_int(u"BootCurrent",
  

•                                      &efi_global_variable_guid,
  

•                                      attributes, sizeof(n), &n, false);
  

•           if (ret != EFI_SUCCESS)
  

•                   goto unload;
  

•           /* try to register load file2 for initrd's */
  

•           if (IS_ENABLED(CONFIG_EFI_LOAD_FILE2_INITRD)) {
  

•                   ret = efi_initrd_register();
  

•                   if (ret != EFI_SUCCESS)
  

•                           goto unload;
  

•           }
  

•   log_debug("trying to load \"%ls\" from %pD\n", lo.label, lo.file_path);
  
  

•           log_info("Booting: %ls\n", lo.label);
  

•   if (EFI_DP_TYPE(lo.file_path, MEDIA_DEVICE, FILE_PATH)) {
  

•           /* file_path doesn't contain a device path */
  

•           ret = try_load_from_short_path(lo.file_path, handle);
  

•   } else if (EFI_DP_TYPE(lo.file_path, MESSAGING_DEVICE, MSG_URI)) {
  

•           if (IS_ENABLED(CONFIG_EFI_HTTP_BOOT))
  

•                   ret = try_load_from_uri_path(
  

•                           (struct efi_device_path_uri *)lo.file_path,
  

•                           lo.label, handle);
  

•           else
  

•                   ret = EFI_LOAD_ERROR;
    } else {
  

•           ret = EFI_LOAD_ERROR;
  

•           ret = try_load_from_media(lo.file_path, handle);
  

•   }
  

•   if (ret != EFI_SUCCESS) {
  

•           log_warning("Loading %ls '%ls' failed\n",
  

•                       varname, lo.label);
  

•           goto error;
  

•   }
  

•   attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
  

•                EFI_VARIABLE_RUNTIME_ACCESS;
  

•   ret = efi_set_variable_int(u"BootCurrent", &efi_global_variable_guid,
  

•                              attributes, sizeof(n), &n, false);
  

•   if (ret != EFI_SUCCESS)
  

•           goto error;
  

•   /* try to register load file2 for initrd's */
  

•   if (IS_ENABLED(CONFIG_EFI_LOAD_FILE2_INITRD)) {
  

•           ret = efi_initrd_register();
  

•           if (ret != EFI_SUCCESS)
  

•                   goto error;
    }
  
  

•   /* Set load options */
  

•   log_info("Booting: %ls\n", lo.label);
  

•   /* Ignore the optional data in auto-generated boot options */
    if (size >= sizeof(efi_guid_t) &&
        !guidcmp(lo.optional_data, &efi_guid_bootmenu_auto_generated))
            size = 0;
  
  

•   /* Set optional data in loaded file protocol */
    if (size) {
            *load_options = malloc(size);
            if (!*load_options) {
  

@@ -683,18 +685,15 @@ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle, } memcpy(*load_options, lo.optional_data, size); ret = efi_set_load_options(*handle, size, *load_options);

•   } else {
  

•           *load_options = NULL;
  

•           if (ret != EFI_SUCCESS)
  

•                   free(load_options);
    }
  
  

error:

•   free(load_option);
  

•   return ret;
  

-unload:

•   if (EFI_CALL(efi_unload_image(*handle)) != EFI_SUCCESS)
  

•   if (ret != EFI_SUCCESS && *handle &&
  

•       EFI_CALL(efi_unload_image(*handle)) != EFI_SUCCESS)
            log_err("Unloading image failed\n");
  

•   free(load_option);
  
    return ret;
  

diff --git a/test/py/tests/test_efi_secboot/test_signed.py b/test/py/tests/test_efi_secboot/test_signed.py index 2f862a259ad..5000a4ab7b6 100644 --- a/test/py/tests/test_efi_secboot/test_signed.py +++ b/test/py/tests/test_efi_secboot/test_signed.py @@ -62,13 +62,13 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert(''HELLO1' failed' in ''.join(output))

•        assert('efi_start_image() returned: 26' in ''.join(output))
  

•        assert('efi_bootmgr_load() returned: 26' in ''.join(output))
         output = u_boot_console.run_command_list([
             'efidebug boot add -b 2 HELLO2 host 0:1 /helloworld.efi -s ""',
             'efidebug boot order 2',
             'efidebug test bootmgr'])
         assert '\'HELLO2\' failed' in ''.join(output)
  

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 2b'):
         # Test Case 2b, authenticated by db
  

@@ -80,7 +80,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 2', 'efidebug test bootmgr']) assert ''HELLO2' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
         output = u_boot_console.run_command_list([
             'efidebug boot order 1',
             'bootefi bootmgr'])
  

@@ -108,7 +108,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 3b'):
         # Test Case 3b, rejected by dbx even if db allows
  

@@ -120,7 +120,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
  

  def test_efi_signed_image_auth4(self, u_boot_console, efi_boot_env): """

@@ -146,7 +146,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
  

  def test_efi_signed_image_auth5(self, u_boot_console, efi_boot_env): """

@@ -196,7 +196,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 5d'):
         # Test Case 5d, rejected if both of signatures are revoked
  

@@ -208,7 +208,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     # Try rejection in reverse order.
     u_boot_console.restart_uboot()
  

@@ -233,7 +233,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
  

  def test_efi_signed_image_auth6(self, u_boot_console, efi_boot_env): """

@@ -268,7 +268,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 6c'):
         # Test Case 6c, rejected by image's digest in dbx
  

@@ -282,7 +282,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
  

  def test_efi_signed_image_auth7(self, u_boot_console, efi_boot_env): """

@@ -310,7 +310,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     # sha512 of an x509 cert in dbx
     u_boot_console.restart_uboot()
  

@@ -333,7 +333,7 @@ class TestEfiSignedImage(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
  

  def test_efi_signed_image_auth8(self, u_boot_console, efi_boot_env): """

@@ -368,4 +368,4 @@ class TestEfiSignedImage(object): 'efidebug test bootmgr']) assert(not 'hELLO, world!' in ''.join(output)) assert(''HELLO1' failed' in ''.join(output))

•        assert('efi_start_image() returned: 26' in ''.join(output))
  

•        assert('efi_bootmgr_load() returned: 26' in ''.join(output))
  

diff --git a/test/py/tests/test_efi_secboot/test_signed_intca.py b/test/py/tests/test_efi_secboot/test_signed_intca.py index 8d9a5f3e7fe..cf906205bc2 100644 --- a/test/py/tests/test_efi_secboot/test_signed_intca.py +++ b/test/py/tests/test_efi_secboot/test_signed_intca.py @@ -43,7 +43,7 @@ class TestEfiSignedImageIntca(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO_a' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 1b'):
         # Test Case 1b, signed and authenticated by root CA
  

@@ -74,7 +74,7 @@ class TestEfiSignedImageIntca(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO_abc' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 2b'):
         # Test Case 2b, signed and authenticated by root CA
  

@@ -84,7 +84,7 @@ class TestEfiSignedImageIntca(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO_abc' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 2c'):
         # Test Case 2c, signed and authenticated by root CA
  

@@ -122,7 +122,7 @@ class TestEfiSignedImageIntca(object): assert 'Hello, world!' in ''.join(output) # Or, # assert ''HELLO_abc' failed' in ''.join(output)

•        # assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        # assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  
     with u_boot_console.log.section('Test Case 3b'):
         # Test Case 3b, revoked by root CA in dbx
  

@@ -132,4 +132,4 @@ class TestEfiSignedImageIntca(object): 'efidebug boot order 1', 'efidebug test bootmgr']) assert ''HELLO_abc' failed' in ''.join(output)

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
  

diff --git a/test/py/tests/test_efi_secboot/test_unsigned.py b/test/py/tests/test_efi_secboot/test_unsigned.py index 7c078f220d0..b4320ae4054 100644 --- a/test/py/tests/test_efi_secboot/test_unsigned.py +++ b/test/py/tests/test_efi_secboot/test_unsigned.py @@ -42,7 +42,7 @@ class TestEfiUnsignedImage(object): output = u_boot_console.run_command_list([ 'efidebug boot order 1', 'efidebug test bootmgr'])

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
         assert 'Hello, world!' not in ''.join(output)
  
  

  def test_efi_unsigned_image_auth2(self, u_boot_console, efi_boot_env):

@@ -95,7 +95,7 @@ class TestEfiUnsignedImage(object): output = u_boot_console.run_command_list([ 'efidebug boot order 1', 'efidebug test bootmgr'])

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
         assert 'Hello, world!' not in ''.join(output)
  
     with u_boot_console.log.section('Test Case 3b'):
  

@@ -113,5 +113,5 @@ class TestEfiUnsignedImage(object): output = u_boot_console.run_command_list([ 'efidebug boot order 1', 'efidebug test bootmgr'])

•        assert 'efi_start_image() returned: 26' in ''.join(output)
  

•        assert 'efi_bootmgr_load() returned: 26' in ''.join(output)
         assert 'Hello, world!' not in ''.join(output)
  

-- 2.43.0

Please adjust the commit message either in a v2 or while merging. Other than that

Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org