Patrick Georgi (pgeorgi@google.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13672
-gerrit
commit dd821745830ef0bb1122f9e253615051421b878c Author: Patrick Georgi pgeorgi@chromium.org Date: Wed Feb 10 18:07:52 2016 +0100
util/cbfstool: Improve heuristic for cbfs header pointer protection
cbfstool has a routine to deal with old images that may encourage it to overwrite the master header. That routine is triggered for "cbfstool add-master-header" prepared images even though these are not at risk, and - worse - destroys the chain structure (through a negative file length), so avoid touching such images.
Change-Id: I9d0bbe3e6300b9b9f3e50347737d1850f83ddad8 Signed-off-by: Patrick Georgi pgeorgi@chromium.org --- util/cbfstool/cbfs_image.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/util/cbfstool/cbfs_image.c b/util/cbfstool/cbfs_image.c index 314ea57..95e6f42 100644 --- a/util/cbfstool/cbfs_image.c +++ b/util/cbfstool/cbfs_image.c @@ -110,11 +110,18 @@ static int cbfs_fix_legacy_size(struct cbfs_image *image, char *hdr_loc) // A bug in old cbfstool may produce extra few bytes (by alignment) and // cause cbfstool to overwrite things after free space -- which is // usually CBFS header on x86. We need to workaround that. + // Except when we run across a file that contains the actual header, + // in which case this image is a safe, new-style + // `cbfstool add-master-header` based image.
struct cbfs_file *entry, *first = NULL, *last = NULL; for (first = entry = cbfs_find_first_entry(image); entry && cbfs_is_valid_entry(image, entry); entry = cbfs_find_next_entry(image, entry)) { + /* Is the header guarded by a CBFS file entry? Then exit */ + if (((char *)entry) + ntohl(entry->offset) == hdr_loc) { + return 0; + } last = entry; } if ((char *)first < (char *)hdr_loc &&