efi_loader: allow writing to FAT

fs_fat_write() is not able to write to subdirectories.

Currently if a filepath with a leading slash is passed, the slash is treated as part of the filename to be created in the root directory.

Strip leading (back-)slashes.

Check that the remaining filename does not contain any illegal characters (<>:"/\|?*). This way we will throw an error when trying to write to a subdirectory.

Signed-off-by Heinrich Schuchardt <[email protected]>

---
 fs/fat/fat_write.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

fs/fat/fat_write.c +17 -1

index 5ca8fcda73c..f32745febb4 100644
@@ -908,9 +908,11 @@ static int do_fat_write(const char *filename,
 void *buffer, loff_t size, volume_info volinfo;
 	fsdata datablock;
 	fsdata *mydata = &datablock;
-	int cursect;
+	int cursect, i;
 	int ret = -1, name_len;
 	char l_filename[VFAT_MAXLEN_BYTES];
+	char bad[2] = " ";
+	const char illegal[] = "<>:\"/\\|?*";
 
 	*actwrite = size;
 	dir_curclust = 0;

@@ -970,6 +972,20 @@ static int do_fat_write(const char *filename,
 void *buffer, loff_t size, }
 	dentptr = (dir_entry *) do_fat_read_at_block;
 
+	/* Strip leading (back-)slashes */
+	while (*filename == '/')
+		++filename;
+	while (*filename == '\\')
+		++filename;
+	/* Check that the filename is valid */
+	for (i = 0; i < strlen(illegal); ++i) {
+		*bad = illegal[i];
+		if (strstr(filename, bad)) {
+			printf("FAT: illegal filename (%s)\n",
 filename);
+			return -1;
+		}
+	}
+
 	name_len = strlen(filename);
 	if (name_len >= VFAT_MAXLEN_BYTES)

name_len = VFAT_MAXLEN_BYTES - 1;

Signed-off-by Heinrich Schuchardt <[email protected]>

---
 lib/efi_selftest/efi_selftest_block_device.c | 56 ++++++++++++++++++++
 1 file changed, 56 insertions(+)

lib/efi_selftest/efi_selftest_block_device.c +6 -0

index 4af8bd8cb28..9209ce678ee 100644
@@ -377,6 +377,7 @@ static int execute(void)
 			"Wrong volume label '%ps', expected 'U-BOOT TEST'\n",
 			system_info.info.volume_label);
 	}
+	/* Read file */
 	ret = root->open(root, &file, (s16 *)L"hello.txt", EFI_FILE_MODE_READ,
 			 0);
 	if (ret != EFI_SUCCESS) {

@@ -389,6 +390,11 @@ static int execute(void)
 		efi_st_error("Failed to read file\n");
 		return EFI_ST_FAILURE;
 	}
+	if (buf_size != 13) {
+		efi_st_error("Wrong number of bytes read: %u\n",
+			     (unsigned int)buf_size);
+		return EFI_ST_FAILURE;
+	}
 	if (efi_st_memcmp(buf, "Hello world!", 12)) {
 		efi_st_error("Unexpected file content\n");
 		return EFI_ST_FAILURE;

lib/efi_selftest/efi_selftest_block_device.c +8 -0

+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to open file\n");
+		return EFI_ST_FAILURE;
+	}
+	buf_size = 7;
+	boottime->set_mem(buf, sizeof(buf), 0);
+	boottime->copy_mem(buf, "U-Boot", buf_size);
+	ret = file->write(file, &buf_size, buf);

lib/efi_selftest/efi_selftest_block_device.c +29 -0

+	/* Verify file */
+	boottime->set_mem(buf, sizeof(buf), 0);
+	ret = root->open(root, &file, (s16 *)L"u-boot.txt", EFI_FILE_MODE_READ,
+			 0);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to open file\n");
+		return EFI_ST_FAILURE;
+	}
+	buf_size = sizeof(buf) - 1;
+	ret = file->read(file, &buf_size, buf);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to read file\n");
+		return EFI_ST_FAILURE;
+	}
+	if (buf_size != 7) {
+		efi_st_error("Wrong number of bytes read: %u\n",
+			     (unsigned int) buf_size);
+		return EFI_ST_FAILURE;
+	}
+	if (efi_st_memcmp(buf, "U-Boot", 7)) {
+		efi_st_error("Unexpected file content %s\n", buf);
+		return EFI_ST_FAILURE;
+	}
+	ret = file->close(file);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to close file\n");
+		return EFI_ST_FAILURE;
+	}
+	ret = root->close(root);
 	if (ret != EFI_SUCCESS) {
 		efi_st_error("Failed to close volume\n");
 		return EFI_ST_FAILURE;

Signature · 1 line

2.17.0

Heinrich,

Quoted 25 lines · Heinrich Schuchardt

Signed-off-by Heinrich Schuchardt <[email protected]>

---
 lib/efi_selftest/efi_selftest_block_device.c | 56 ++++++++++++++++++++
 1 file changed, 56 insertions(+)

lib/efi_selftest/efi_selftest_block_device.c +5 -0

index 4af8bd8cb28..9209ce678ee 100644
@@ -377,6 +377,7 @@ static int execute(void)
 			"Wrong volume label '%ps', expected 'U-BOOT TEST'\n",
 			system_info.info.volume_label);
 	}
+	/* Read file */
 	ret = root->open(root, &file, (s16 *)L"hello.txt", EFI_FILE_MODE_READ,
 			 0);
 	if (ret != EFI_SUCCESS) {

@@ -389,6 +390,11 @@ static int execute(void)
 		efi_st_error("Failed to read file\n");
 		return EFI_ST_FAILURE;
 	}
+	if (buf_size != 13) {
+		efi_st_error("Wrong number of bytes read: %u\n",
+			     (unsigned int)buf_size);
+		return EFI_ST_FAILURE;

lib/efi_selftest/efi_selftest_block_device.c static int execute(void) · line 407

Quoted 8 lines

lib/efi_selftest/efi_selftest_block_device.c +1 -0

+	}
 	if (efi_st_memcmp(buf, "Hello world!", 12)) {
 		efi_st_error("Unexpected file content\n");
 		return EFI_ST_FAILURE;

@@ -399,6 +405,56 @@ static int execute(void)
 		return EFI_ST_FAILURE;
 	}
 	ret = root->close(root);

We should not close 'root' here as

lib/efi_selftest/efi_selftest_block_device.c static int execute(void) · line 410

Quoted 3 lines

lib/efi_selftest/efi_selftest_block_device.c +3 -0

+	/* Write file */
+	ret = root->open(root, &file, (s16 *)L"u-boot.txt",
+			 EFI_FILE_MODE_WRITE | EFI_FILE_MODE_CREATE, 0);

we will use it here.

Quoted 8 lines

lib/efi_selftest/efi_selftest_block_device.c +8 -0

+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to open file\n");
+		return EFI_ST_FAILURE;
+	}
+	buf_size = 7;
+	boottime->set_mem(buf, sizeof(buf), 0);
+	boottime->copy_mem(buf, "U-Boot", buf_size);
+	ret = file->write(file, &buf_size, buf);

lib/efi_selftest/efi_selftest_block_device.c static int execute(void) · line 428

Quoted 10 lines

lib/efi_selftest/efi_selftest_block_device.c +10 -0

+	if (ret != EFI_SUCCESS || buf_size != 7) {
+		efi_st_error("Failed to write file\n");
+		return EFI_ST_FAILURE;
+	}
+	ret = file->close(file);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to close file\n");
+		return EFI_ST_FAILURE;
+	}
+	ret = root->close(root);

ditto

Thanks,
-Takahiro AKASHI

Quoted 35 lines

lib/efi_selftest/efi_selftest_block_device.c +29 -0

+	/* Verify file */
+	boottime->set_mem(buf, sizeof(buf), 0);
+	ret = root->open(root, &file, (s16 *)L"u-boot.txt", EFI_FILE_MODE_READ,
+			 0);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to open file\n");
+		return EFI_ST_FAILURE;
+	}
+	buf_size = sizeof(buf) - 1;
+	ret = file->read(file, &buf_size, buf);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to read file\n");
+		return EFI_ST_FAILURE;
+	}
+	if (buf_size != 7) {
+		efi_st_error("Wrong number of bytes read: %u\n",
+			     (unsigned int) buf_size);
+		return EFI_ST_FAILURE;
+	}
+	if (efi_st_memcmp(buf, "U-Boot", 7)) {
+		efi_st_error("Unexpected file content %s\n", buf);
+		return EFI_ST_FAILURE;
+	}
+	ret = file->close(file);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Failed to close file\n");
+		return EFI_ST_FAILURE;
+	}
+	ret = root->close(root);
 	if (ret != EFI_SUCCESS) {
 		efi_st_error("Failed to close volume\n");
 		return EFI_ST_FAILURE;

Signature · 1 line

2.17.0