[PATCHv3] Set last_comp_version correctly in new dtb and fix potential version issues in fdt_open_into

[PATCHv3] Set last_comp_version correctly in new dtb and fix potential version issues in fdt_open_into

[Justin Covell]

Changes in v3: 
- Remove noop version sets 
- Set version correctly on loaded fdt in fdt_open_into

Fixes: f1879e1a50eb ("Add limited read-only support for older (V2 and V3) device tree to libfdt.")

Signed-off-by: Justin Covell <jujugoboom-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

---
 libfdt/fdt_rw.c | 4 +++-
 libfdt/fdt_sw.c | 2 +-
 libfdt/libfdt.h | 1 +
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index 68887b9..f13458d 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) ||
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

Re: [PATCHv3] Set last_comp_version correctly in new dtb and fix potential version issues in fdt_open_into

[David Gibson]

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On Mon, Dec 28, 2020 at 08:17:49PM -0800, Justin Covell wrote:
> Changes in v3: 
> - Remove noop version sets 
> - Set version correctly on loaded fdt in fdt_open_into
> 
> Fixes: f1879e1a50eb ("Add limited read-only support for older (V2 and V3) device tree to libfdt.")
> 
> Signed-off-by: Justin Covell <jujugoboom-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Applied, thanks.

> 
> ---
>  libfdt/fdt_rw.c | 4 +++-
>  libfdt/fdt_sw.c | 2 +-
>  libfdt/libfdt.h | 1 +
>  3 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
> index 68887b9..f13458d 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) ||
> 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 */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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