Carve out a function to check that a buffer contains a PE-COFF image.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- include/efi_loader.h | 2 + lib/efi_loader/efi_image_loader.c | 80 ++++++++++++++++++------------- 2 files changed, 48 insertions(+), 34 deletions(-)
diff --git a/include/efi_loader.h b/include/efi_loader.h index 0fc2255f3f..63459ea649 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -453,6 +453,8 @@ efi_status_t efi_set_watchdog(unsigned long timeout);
/* Called from places to check whether a timer expired */ void efi_timer_check(void); +/* Check if a buffer contains a PE-COFF image */ +efi_status_t efi_check_pe(void *buffer, size_t size, void **nt_header); /* PE loader implementation */ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, size_t efi_size, diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c index 94f76ef6b8..d4dd9e9433 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -675,6 +675,46 @@ static bool efi_image_authenticate(void *efi, size_t efi_size) } #endif /* CONFIG_EFI_SECURE_BOOT */
+ +/** + * efi_check_pe() - check if a memory buffer contains a PE-COFF image + * + * @buffer: buffer to check + * @size: size of buffer + * @nt_header: on return pointer to NT header of PE-COFF image + * Return: EFI_SUCCESS if the buffer contains a PE-COFF image + */ +efi_status_t efi_check_pe(void *buffer, size_t size, void **nt_header) +{ + IMAGE_DOS_HEADER *dos = buffer; + IMAGE_NT_HEADERS32 *nt; + + if (size < sizeof(*dos)) + return EFI_INVALID_PARAMETER; + + /* Check for DOS magix */ + if (dos->e_magic != IMAGE_DOS_SIGNATURE) + return EFI_INVALID_PARAMETER; + + /* + * Check if the image section header fits into the file. Knowing that at + * least one section header follows we only need to check for the length + * of the 64bit header which is longer than the 32bit header. + */ + if (size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS32)) + return EFI_INVALID_PARAMETER; + nt = (IMAGE_NT_HEADERS32 *)((u8 *)buffer + dos->e_lfanew); + + /* Check for PE-COFF magic */ + if (nt->Signature != IMAGE_NT_SIGNATURE) + return EFI_INVALID_PARAMETER; + + if (nt_header) + *nt_header = nt; + + return EFI_SUCCESS; +} + /** * efi_load_pe() - relocate EFI binary * @@ -705,36 +745,10 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, int supported = 0; efi_status_t ret;
- /* Sanity check for a file header */ - if (efi_size < sizeof(*dos)) { - log_err("Truncated DOS Header\n"); - ret = EFI_LOAD_ERROR; - goto err; - } - - dos = efi; - if (dos->e_magic != IMAGE_DOS_SIGNATURE) { - log_err("Invalid DOS Signature\n"); - ret = EFI_LOAD_ERROR; - goto err; - } - - /* - * Check if the image section header fits into the file. Knowing that at - * least one section header follows we only need to check for the length - * of the 64bit header which is longer than the 32bit header. - */ - if (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS64)) { - log_err("Invalid offset for Extended Header\n"); - ret = EFI_LOAD_ERROR; - goto err; - } - - nt = (void *) ((char *)efi + dos->e_lfanew); - if (nt->Signature != IMAGE_NT_SIGNATURE) { - log_err("Invalid NT Signature\n"); - ret = EFI_LOAD_ERROR; - goto err; + ret = efi_check_pe(efi, efi_size, (void **)&nt); + if (ret != EFI_SUCCESS) { + log_err("Not a PE-COFF file\n"); + return EFI_LOAD_ERROR; }
for (i = 0; machines[i]; i++) @@ -746,8 +760,7 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, if (!supported) { log_err("Machine type 0x%04x is not supported\n", nt->FileHeader.Machine); - ret = EFI_LOAD_ERROR; - goto err; + return EFI_LOAD_ERROR; }
num_sections = nt->FileHeader.NumberOfSections; @@ -757,8 +770,7 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, if (efi_size < ((void *)sections + sizeof(sections[0]) * num_sections - efi)) { log_err("Invalid number of sections: %d\n", num_sections); - ret = EFI_LOAD_ERROR; - goto err; + return EFI_LOAD_ERROR; }
/* Authenticate an image */ -- 2.29.2