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authorDavid Gibson <david@gibson.dropbear.id.au>2018-04-10 17:06:18 +1000
committerSebastian Huber <sebastian.huber@embedded-brains.de>2018-07-19 07:01:11 +0200
commitc4267b1e5f6ef5eb90d7cfdccdec196c9a7d3fec (patch)
tree7cd0675493bca039b662f981e85638c87bde62a4 /cpukit/dtc
parent85d17691faa51925c5bf2316f80612ebb02f7c89 (diff)
downloadrtems-c4267b1e5f6ef5eb90d7cfdccdec196c9a7d3fec.tar.bz2
libfdt: Improve sequential write state checking
When creating a tree with the sequential write functions, certain things have to be done in a certain order. You must create the memory reserve map and only then can you create the actual tree structure. The -FDT_ERR_BADSTATE return code is for if you try to do things out of order. However, we weren't checking that very thoroughly, so it was possible to generate a corrupted blob if, for example, you started calling fdt_begin_node() etc. before calling fdt_finish_reservemap(). This makes the state checking more thorough disallow that. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'cpukit/dtc')
-rw-r--r--cpukit/dtc/libfdt/fdt_sw.c89
1 files changed, 75 insertions, 14 deletions
diff --git a/cpukit/dtc/libfdt/fdt_sw.c b/cpukit/dtc/libfdt/fdt_sw.c
index 9f6fe2085d..178b3657b0 100644
--- a/cpukit/dtc/libfdt/fdt_sw.c
+++ b/cpukit/dtc/libfdt/fdt_sw.c
@@ -57,9 +57,10 @@
static int fdt_sw_probe_(void *fdt)
{
- if (fdt_magic(fdt) != FDT_SW_MAGIC)
+ if (fdt_magic(fdt) == FDT_MAGIC)
+ return -FDT_ERR_BADSTATE;
+ else if (fdt_magic(fdt) != FDT_SW_MAGIC)
return -FDT_ERR_BADMAGIC;
- /* FIXME: should check more details about the header state */
return 0;
}
@@ -70,6 +71,61 @@ static int fdt_sw_probe_(void *fdt)
return err; \
}
+/* 'memrsv' state: Initial state after fdt_create()
+ *
+ * Allowed functions:
+ * fdt_add_reservmap_entry()
+ * fdt_finish_reservemap() [moves to 'struct' state]
+ */
+static int fdt_sw_probe_memrsv_(void *fdt)
+{
+ int err = fdt_sw_probe_(fdt);
+ if (err)
+ return err;
+
+ if (fdt_off_dt_strings(fdt) != 0)
+ return -FDT_ERR_BADSTATE;
+ return 0;
+}
+
+#define FDT_SW_PROBE_MEMRSV(fdt) \
+ { \
+ int err; \
+ if ((err = fdt_sw_probe_memrsv_(fdt)) != 0) \
+ return err; \
+ }
+
+/* 'struct' state: Enter this state after fdt_finish_reservemap()
+ *
+ * Allowed functions:
+ * fdt_begin_node()
+ * fdt_end_node()
+ * fdt_property*()
+ * fdt_finish() [moves to 'complete' state]
+ */
+static int fdt_sw_probe_struct_(void *fdt)
+{
+ int err = fdt_sw_probe_(fdt);
+ if (err)
+ return err;
+
+ if (fdt_off_dt_strings(fdt) != fdt_totalsize(fdt))
+ return -FDT_ERR_BADSTATE;
+ return 0;
+}
+
+#define FDT_SW_PROBE_STRUCT(fdt) \
+ { \
+ int err; \
+ if ((err = fdt_sw_probe_struct_(fdt)) != 0) \
+ return err; \
+ }
+
+/* 'complete' state: Enter this state after fdt_finish()
+ *
+ * Allowed functions: none
+ */
+
static void *fdt_grab_space_(void *fdt, size_t len)
{
int offset = fdt_size_dt_struct(fdt);
@@ -102,7 +158,7 @@ int fdt_create(void *buf, int bufsize)
fdt_set_off_mem_rsvmap(fdt, FDT_ALIGN(sizeof(struct fdt_header),
sizeof(struct fdt_reserve_entry)));
fdt_set_off_dt_struct(fdt, fdt_off_mem_rsvmap(fdt));
- fdt_set_off_dt_strings(fdt, bufsize);
+ fdt_set_off_dt_strings(fdt, 0);
return 0;
}
@@ -133,8 +189,9 @@ int fdt_resize(void *fdt, void *buf, int bufsize)
memmove(buf, fdt, headsize);
}
- fdt_set_off_dt_strings(buf, bufsize);
fdt_set_totalsize(buf, bufsize);
+ if (fdt_off_dt_strings(buf))
+ fdt_set_off_dt_strings(buf, bufsize);
return 0;
}
@@ -144,10 +201,7 @@ int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
struct fdt_reserve_entry *re;
int offset;
- FDT_SW_PROBE(fdt);
-
- if (fdt_size_dt_struct(fdt))
- return -FDT_ERR_BADSTATE;
+ FDT_SW_PROBE_MEMRSV(fdt);
offset = fdt_off_dt_struct(fdt);
if ((offset + sizeof(*re)) > fdt_totalsize(fdt))
@@ -164,16 +218,23 @@ int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
int fdt_finish_reservemap(void *fdt)
{
- return fdt_add_reservemap_entry(fdt, 0, 0);
+ int err = fdt_add_reservemap_entry(fdt, 0, 0);
+
+ if (err)
+ return err;
+
+ fdt_set_off_dt_strings(fdt, fdt_totalsize(fdt));
+ return 0;
}
int fdt_begin_node(void *fdt, const char *name)
{
struct fdt_node_header *nh;
- int namelen = strlen(name) + 1;
+ int namelen;
- FDT_SW_PROBE(fdt);
+ FDT_SW_PROBE_STRUCT(fdt);
+ namelen = strlen(name) + 1;
nh = fdt_grab_space_(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
if (! nh)
return -FDT_ERR_NOSPACE;
@@ -187,7 +248,7 @@ int fdt_end_node(void *fdt)
{
fdt32_t *en;
- FDT_SW_PROBE(fdt);
+ FDT_SW_PROBE_STRUCT(fdt);
en = fdt_grab_space_(fdt, FDT_TAGSIZE);
if (! en)
@@ -225,7 +286,7 @@ int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp)
struct fdt_property *prop;
int nameoff;
- FDT_SW_PROBE(fdt);
+ FDT_SW_PROBE_STRUCT(fdt);
nameoff = fdt_find_add_string_(fdt, name);
if (nameoff == 0)
@@ -262,7 +323,7 @@ int fdt_finish(void *fdt)
uint32_t tag;
int offset, nextoffset;
- FDT_SW_PROBE(fdt);
+ FDT_SW_PROBE_STRUCT(fdt);
/* Add terminator */
end = fdt_grab_space_(fdt, sizeof(*end));