Hi,
I've added checks to fdt_open_into to validate the version before reading into buffer, as well as maintaining the accurate
version information of the fdt when loaded into the buffer. Hopefully this would help stop any issues with reading a
fdt with a lower than compatible verison into a buffer and it being misrepresented as a current version.
Signed-off-by: Justin Covell <jujugoboom@xxxxxxxxx>
---
libfdt/fdt_rw.c | 10 ++++++----
libfdt/fdt_sw.c | 2 +-
libfdt/libfdt.h | 1 +
3 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index 68887b9..feab26c 100644
--- a/libfdt/fdt_rw.c
+++ b/libfdt/fdt_rw.c
@@ -428,12 +428,14 @@ int fdt_open_into(const void *fdt, void *buf, int bufsize)
if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
struct_size = fdt_size_dt_struct(fdt);
- } else {
+ } else if (fdt_version(fdt) == 16) {
struct_size = 0;
while (fdt_next_tag(fdt, struct_size, &struct_size) != FDT_END)
;
if (struct_size < 0)
return struct_size;
+ } else {
+ return -FDT_ERR_BADVERSION;
}
if (can_assume(LIBFDT_ORDER) ||
@@ -442,7 +444,7 @@ int fdt_open_into(const void *fdt, void *buf, int bufsize)
err = fdt_move(fdt, buf, bufsize);
if (err)
return err;
- fdt_set_version(buf, 17);
+ fdt_set_version(buf, fdt_version(fdt));
fdt_set_size_dt_struct(buf, struct_size);
fdt_set_totalsize(buf, bufsize);
return 0;
@@ -470,8 +472,8 @@ int fdt_open_into(const void *fdt, void *buf, int bufsize)
fdt_set_magic(buf, FDT_MAGIC);
fdt_set_totalsize(buf, bufsize);
- fdt_set_version(buf, 17);
- fdt_set_last_comp_version(buf, 16);
+ fdt_set_version(buf, fdt_version(fdt));
+ fdt_set_last_comp_version(buf, fdt_last_comp_version(fdt));
fdt_set_boot_cpuid_phys(buf, fdt_boot_cpuid_phys(fdt));
return 0;
diff --git a/libfdt/fdt_sw.c b/libfdt/fdt_sw.c
index 68b543c..4c569ee 100644
--- a/libfdt/fdt_sw.c
+++ b/libfdt/fdt_sw.c
@@ -377,7 +377,7 @@ int fdt_finish(void *fdt)
fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));
/* And fix up fields that were keeping intermediate state. */
- fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
+ fdt_set_last_comp_version(fdt, FDT_LAST_COMPATIBLE_VERSION);
fdt_set_magic(fdt, FDT_MAGIC);
return 0;
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 2bc16a8..73467f7 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -14,6 +14,7 @@ extern "C" {
#endif
#define FDT_FIRST_SUPPORTED_VERSION 0x02
+#define FDT_LAST_COMPATIBLE_VERSION 0x10
#define FDT_LAST_SUPPORTED_VERSION 0x11
/* Error codes: informative error codes */
--
2.25.1
