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device_tree: Add version checks 

This patch adds a few more sanity checks to the FDT header parsing to
make sure that our code can support the version that is passed in.

This patch was adapted from depthcharge's http://crosreview.com/1536384

Change-Id: I06c112f540213c8db7c2455c2e8a4e8e4f337b78
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32862
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Julius Werner 2019-05-03 17:58:07 -07:00 committed by Patrick Georgi
parent 9636a106d4
commit 73eaec8168
3 changed files with 23 additions and 6 deletions
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3
src/include/device_tree.h
View File

@ -33,7 +33,7 @@ struct fdt_header {
uint32_t reserve_map_offset; uint32_t reserve_map_offset;
uint32_t version; uint32_t version;
uint32_t last_compatible_version; uint32_t last_comp_version;
uint32_t boot_cpuid_phys; uint32_t boot_cpuid_phys;
@ -42,6 +42,7 @@ struct fdt_header {
}; };
#define FDT_HEADER_MAGIC 0xd00dfeed #define FDT_HEADER_MAGIC 0xd00dfeed
#define FDT_SUPPORTED_VERSION 17
#define FDT_TOKEN_BEGIN_NODE 1 #define FDT_TOKEN_BEGIN_NODE 1
#define FDT_TOKEN_END_NODE 2 #define FDT_TOKEN_END_NODE 2
#define FDT_TOKEN_PROPERTY 3 #define FDT_TOKEN_PROPERTY 3

18
src/lib/device_tree.c
View File

@ -220,6 +220,24 @@ struct device_tree *fdt_unflatten(const void *blob)
const struct fdt_header *header = (const struct fdt_header *)blob; const struct fdt_header *header = (const struct fdt_header *)blob;
tree->header = header; tree->header = header;
uint32_t magic = be32toh(header->magic);
uint32_t version = be32toh(header->version);
uint32_t last_comp_version = be32toh(header->last_comp_version);
if (magic != FDT_HEADER_MAGIC) {
printk(BIOS_DEBUG, "Invalid device tree magic %#.8x!\n", magic);
return NULL;
}
if (last_comp_version > FDT_SUPPORTED_VERSION) {
printk(BIOS_DEBUG, "Unsupported device tree version %u(>=%u)\n",
version, last_comp_version);
return NULL;
}
if (version > FDT_SUPPORTED_VERSION)
printk(BIOS_DEBUG,
"NOTE: FDT version %u too new, should add support!\n",
version);
uint32_t struct_offset = be32toh(header->structure_offset); uint32_t struct_offset = be32toh(header->structure_offset);
uint32_t strings_offset = be32toh(header->strings_offset); uint32_t strings_offset = be32toh(header->strings_offset);
uint32_t reserve_offset = be32toh(header->reserve_map_offset); uint32_t reserve_offset = be32toh(header->reserve_map_offset);

8
src/lib/fit.c
View File

@ -423,19 +423,17 @@ static void fit_update_compat(const void *fdt_blob,
struct fit_config_node *fit_load(void *fit) struct fit_config_node *fit_load(void *fit)
{ {
struct fdt_header *header = (struct fdt_header *)fit;
struct fit_image_node *image; struct fit_image_node *image;
struct fit_config_node *config; struct fit_config_node *config;
struct compat_string_entry *compat_node; struct compat_string_entry *compat_node;
printk(BIOS_DEBUG, "FIT: Loading FIT from %p\n", fit); printk(BIOS_DEBUG, "FIT: Loading FIT from %p\n", fit);
if (be32toh(header->magic) != FDT_HEADER_MAGIC) { struct device_tree *tree = fdt_unflatten(fit);
printk(BIOS_ERR, "FIT: Bad header magic value 0x%08x.\n", if (!tree) {
be32toh(header->magic)); printk(BIOS_ERR, "ERROR: Failed to unflatten FIT image!\n");
return NULL; return NULL;
} }
struct device_tree *tree = fdt_unflatten(fit);
const char *default_config_name = NULL; const char *default_config_name = NULL;
struct fit_config_node *default_config = NULL; struct fit_config_node *default_config = NULL;