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| author | Patrick Georgi <pgeorgi@chromium.org> | 2016-02-10 18:07:52 +0100 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2016-02-12 19:23:08 +0100 |
| commit | 343ea08388583d66c4145f5da3bea8828c5c0daf (patch) | |
| tree | a79e9e87c655c1ba965c1ba69adc32e36674cf59 /util/cbfstool | |
| parent | 0a07c5c4a033a27058aad2fd0a3a192f3c1edf9b (diff) | |
| download | coreboot-343ea08388583d66c4145f5da3bea8828c5c0daf.tar.xz | |
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>
Reviewed-on: https://review.coreboot.org/13672
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
Diffstat (limited to 'util/cbfstool')
| -rw-r--r-- | util/cbfstool/cbfs_image.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/util/cbfstool/cbfs_image.c b/util/cbfstool/cbfs_image.c index 314ea5741d..95e6f42b17 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 && |