libfdt: upgrade to upstream dtc.git 243176c

Upgrade libfdt/ to github.com/dgibson/dtc.git 243176c ("Fix bogus
error on rebuild")

This copies dtc/libfdt/ to skiboot/libfdt/, with the only change in
that directory being the addition of README.skiboot and Makefile.inc.

This adds about 14kB text, 2.5kB compressed xz. This could be reduced
or mostly eliminated by cutting out fdt version checks and unused
code, but tracking upstream is a bigger benefit at the moment.

This loses commits:

  14ed2b842f61 ("libfdt: add basic sanity check to fdt_open_into")
  bc7bb3d12bc1 ("sparse: fix declaration of fdt_strerror")

As well as some prehistoric similar kinds of things, which is the
punishment for us not being good downstream citizens and sending
things upstream! Syncing to upstream will make that effort simpler
in future.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

1 files changed, 130 insertions, 12 deletions

diff --git a/libfdt/fdt.c b/libfdt/fdt.c
index b1130c2..ae03b11 100644
--- a/libfdt/fdt.c
+++ b/libfdt/fdt.c
@@ -55,7 +55,12 @@
 
 #include "libfdt_internal.h"
 
-int fdt_check_header(const void *fdt)
+/*
+ * Minimal sanity check for a read-only tree. fdt_ro_probe_() checks
+ * that the given buffer contains what appears to be a flattened
+ * device tree with sane information in its header.
+ */
+int fdt_ro_probe_(const void *fdt)
 {
 	if (fdt_magic(fdt) == FDT_MAGIC) {
 		/* Complete tree */
@@ -74,25 +79,98 @@ int fdt_check_header(const void *fdt)
 	return 0;
 }
 
+static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
+{
+	return (off >= hdrsize) && (off <= totalsize);
+}
+
+static int check_block_(uint32_t hdrsize, uint32_t totalsize,
+			uint32_t base, uint32_t size)
+{
+	if (!check_off_(hdrsize, totalsize, base))
+		return 0; /* block start out of bounds */
+	if ((base + size) < base)
+		return 0; /* overflow */
+	if (!check_off_(hdrsize, totalsize, base + size))
+		return 0; /* block end out of bounds */
+	return 1;
+}
+
+size_t fdt_header_size_(uint32_t version)
+{
+	if (version <= 1)
+		return FDT_V1_SIZE;
+	else if (version <= 2)
+		return FDT_V2_SIZE;
+	else if (version <= 3)
+		return FDT_V3_SIZE;
+	else if (version <= 16)
+		return FDT_V16_SIZE;
+	else
+		return FDT_V17_SIZE;
+}
+
+int fdt_check_header(const void *fdt)
+{
+	size_t hdrsize;
+
+	if (fdt_magic(fdt) != FDT_MAGIC)
+		return -FDT_ERR_BADMAGIC;
+	hdrsize = fdt_header_size(fdt);
+	if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
+	    || (fdt_last_comp_version(fdt) > FDT_LAST_SUPPORTED_VERSION))
+		return -FDT_ERR_BADVERSION;
+	if (fdt_version(fdt) < fdt_last_comp_version(fdt))
+		return -FDT_ERR_BADVERSION;
+
+	if ((fdt_totalsize(fdt) < hdrsize)
+	    || (fdt_totalsize(fdt) > INT_MAX))
+		return -FDT_ERR_TRUNCATED;
+
+	/* Bounds check memrsv block */
+	if (!check_off_(hdrsize, fdt_totalsize(fdt), fdt_off_mem_rsvmap(fdt)))
+		return -FDT_ERR_TRUNCATED;
+
+	/* Bounds check structure block */
+	if (fdt_version(fdt) < 17) {
+		if (!check_off_(hdrsize, fdt_totalsize(fdt),
+				fdt_off_dt_struct(fdt)))
+			return -FDT_ERR_TRUNCATED;
+	} else {
+		if (!check_block_(hdrsize, fdt_totalsize(fdt),
+				  fdt_off_dt_struct(fdt),
+				  fdt_size_dt_struct(fdt)))
+			return -FDT_ERR_TRUNCATED;
+	}
+
+	/* Bounds check strings block */
+	if (!check_block_(hdrsize, fdt_totalsize(fdt),
+			  fdt_off_dt_strings(fdt), fdt_size_dt_strings(fdt)))
+		return -FDT_ERR_TRUNCATED;
+
+	return 0;
+}
+
 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
 {
-	const char *p;
+	unsigned absoffset = offset + fdt_off_dt_struct(fdt);
+
+	if ((absoffset < offset)
+	    || ((absoffset + len) < absoffset)
+	    || (absoffset + len) > fdt_totalsize(fdt))
+		return NULL;
 
 	if (fdt_version(fdt) >= 0x11)
 		if (((offset + len) < offset)
 		    || ((offset + len) > fdt_size_dt_struct(fdt)))
 			return NULL;
 
-	p = _fdt_offset_ptr(fdt, offset);
-
-	if (p + len < p)
-		return NULL;
-	return p;
+	return fdt_offset_ptr_(fdt, offset);
 }
 
 uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 {
-	const uint32_t *tagp, *lenp;
+	const fdt32_t *tagp, *lenp;
 	uint32_t tag;
 	int offset = startoffset;
 	const char *p;
@@ -122,6 +200,9 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 		/* skip-name offset, length and value */
 		offset += sizeof(struct fdt_property) - FDT_TAGSIZE
 			+ fdt32_to_cpu(*lenp);
+		if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 &&
+		    ((offset - fdt32_to_cpu(*lenp)) % 8) != 0)
+			offset += 4;
 		break;
 
 	case FDT_END:
@@ -140,7 +221,7 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 	return tag;
 }
 
-int _fdt_check_node_offset(const void *fdt, int offset)
+int fdt_check_node_offset_(const void *fdt, int offset)
 {
 	if ((offset < 0) || (offset % FDT_TAGSIZE)
 	    || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
@@ -149,13 +230,22 @@ int _fdt_check_node_offset(const void *fdt, int offset)
 	return offset;
 }
 
+int fdt_check_prop_offset_(const void *fdt, int offset)
+{
+	if ((offset < 0) || (offset % FDT_TAGSIZE)
+	    || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
+		return -FDT_ERR_BADOFFSET;
+
+	return offset;
+}
+
 int fdt_next_node(const void *fdt, int offset, int *depth)
 {
 	int nextoffset = 0;
 	uint32_t tag;
 
 	if (offset >= 0)
-		if ((nextoffset = _fdt_check_node_offset(fdt, offset)) < 0)
+		if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
 			return nextoffset;
 
 	do {
@@ -189,7 +279,35 @@ int fdt_next_node(const void *fdt, int offset, int *depth)
 	return offset;
 }
 
-const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
+int fdt_first_subnode(const void *fdt, int offset)
+{
+	int depth = 0;
+
+	offset = fdt_next_node(fdt, offset, &depth);
+	if (offset < 0 || depth != 1)
+		return -FDT_ERR_NOTFOUND;
+
+	return offset;
+}
+
+int fdt_next_subnode(const void *fdt, int offset)
+{
+	int depth = 1;
+
+	/*
+	 * With respect to the parent, the depth of the next subnode will be
+	 * the same as the last.
+	 */
+	do {
+		offset = fdt_next_node(fdt, offset, &depth);
+		if (offset < 0 || depth < 1)
+			return -FDT_ERR_NOTFOUND;
+	} while (depth > 1);
+
+	return offset;
+}
+
+const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
 {
 	int len = strlen(s) + 1;
 	const char *last = strtab + tabsize - len;
@@ -203,7 +321,7 @@ const char *_fdt_find_string(const char *strtab, int tabsize, const char *s)
 
 int fdt_move(const void *fdt, void *buf, int bufsize)
 {
-	FDT_CHECK_HEADER(fdt);
+	FDT_RO_PROBE(fdt);
 
 	if (fdt_totalsize(fdt) > bufsize)
 		return -FDT_ERR_NOSPACE;