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device_tree: Add version checks

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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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18
src/lib/device_tree.c
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@ -220,6 +220,24 @@ struct device_tree *fdt_unflatten(const void *blob)
const struct fdt_header *header = (const struct fdt_header *)blob;
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 strings_offset = be32toh(header->strings_offset);
uint32_t reserve_offset = be32toh(header->reserve_map_offset);