From: Jan Luebbe <jlu@xxxxxxxxxxxxxx>
Signed-off-by: Jan Luebbe <jlu@xxxxxxxxxxxxxx>
Signed-off-by: Ulrich Ölmann <u.oelmann@xxxxxxxxxxxxxx>
---
common/Kconfig | 9 ++++++
common/Makefile | 1 +
common/barebox-image.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/common.h | 9 ++++++
4 files changed, 104 insertions(+)
create mode 100644 common/barebox-image.c
diff --git a/common/Kconfig b/common/Kconfig
index 928db0a159e1..bebbb614509d 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -580,6 +580,15 @@ config IMD_TARGET
depends on IMD
depends on !SANDBOX
+config VERIFY_EMBEDDED_CRC
+ prompt "Verify the CRC checksum embedded into barebox images"
+ bool
+ select CRC32
+ help
+ If you say Y here, the CRC checksum that is embedded into every
+ barebox image directly after the header can be verified to guarantee
+ the integrity of the image.
+
config KERNEL_INSTALL_TARGET
bool
depends on !SANDBOX
diff --git a/common/Makefile b/common/Makefile
index 99681e21215b..0106f0fe7bd9 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_STATE) += state.o
obj-$(CONFIG_RATP) += ratp.o
obj-$(CONFIG_UIMAGE) += image.o uimage.o
obj-$(CONFIG_FITIMAGE) += image-fit.o
+obj-$(CONFIG_VERIFY_EMBEDDED_CRC) += barebox-image.o
obj-$(CONFIG_MENUTREE) += menutree.o
obj-$(CONFIG_EFI_GUID) += efi-guid.o
obj-$(CONFIG_EFI_DEVICEPATH) += efi-devicepath.o
diff --git a/common/barebox-image.c b/common/barebox-image.c
new file mode 100644
index 000000000000..733d9ea2ecdf
--- /dev/null
+++ b/common/barebox-image.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2016 Pengutronix, Jan Luebbe <j.luebbe@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <common.h>
+#include <io.h>
+#include <filetype.h>
+
+static inline size_t get_barebox_head_size(const void *buf)
+{
+ if (is_barebox_arm_head(buf))
+ return ARM_HEAD_SIZE;
+ else if (is_barebox_mips_head(buf))
+ return MIPS_HEAD_SIZE;
+
+ return 0;
+}
+
+static inline size_t get_barebox_head_size_offset(const void *buf)
+{
+ if (is_barebox_arm_head(buf))
+ return ARM_HEAD_SIZE_OFFSET;
+ else if (is_barebox_mips_head(buf))
+ return MIPS_HEAD_SIZE_OFFSET;
+
+ return 0;
+}
+
+bool barebox_verify_image(void *buf, size_t bufsize)
+{
+ unsigned int *psize;
+ size_t head_size;
+ uint32_t crc = 0;
+ uint32_t *p;
+
+ if (bufsize < ARM_HEAD_SIZE) {
+ pr_err("buffer is smaller than ARM_HEAD_SIZE\n");
+ return false;
+ }
+
+ head_size = get_barebox_head_size(buf);
+ if (!head_size) {
+ pr_err("image does not contain a barebox header\n");
+ return false;
+ }
+
+ psize = buf + get_barebox_head_size_offset(buf);
+
+ if (bufsize < *psize) {
+ pr_err("buffer is too small for image\n");
+ return false;
+ }
+
+ if (*psize < head_size + 2 * sizeof(uint32_t)) {
+ pr_err("image is too small\n");
+ return false;
+ }
+
+ p = buf + head_size;
+
+ if (strcmp((const char*) p, BAREBOX_CRC_MAGIC_VALUE)) {
+ pr_debug("image does not contain a checksum\n");
+ return true;
+ }
+
+ crc = crc32(crc, buf, head_size + sizeof(uint32_t));
+ crc = crc32(crc, buf + head_size + 2 * sizeof(uint32_t),
+ *psize - (head_size + 2 * sizeof(uint32_t)));
+ crc = cpu_to_be32(crc);
+
+ if (crc != *(p + 1)) {
+ pr_err("embedded checksum is faulty\n");
+ return false;
+ }
+
+ return true;
+}
diff --git a/include/common.h b/include/common.h
index 680a0affb6bc..9200328c3e10 100644
--- a/include/common.h
+++ b/include/common.h
@@ -164,4 +164,13 @@ static inline bool region_overlap(unsigned long starta, unsigned long lena,
return 1;
}
+#ifdef CONFIG_VERIFY_EMBEDDED_CRC
+bool barebox_verify_image(void*, size_t);
+#else
+static inline bool barebox_verify_image(void *buf, size_t bufsize)
+{
+ return true;
+}
+#endif
+
#endif /* __COMMON_H_ */
--
2.8.1
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