futility: fix segfault on short files
Verify the size of the buffer read from the file before trying to use 1KB of
it for the new rwsig format detection.
Add a new test case with a short file containing only 4 bytes of unknown
data and run "futility show" on it.
BRANCH=smaug
BUG=none
TEST=futility show foobar.pub.pem
where foobar.pub.pem is a 451-byte file.
check that "make runtests" passes with the fix
and fails without it with the following message :
test_file_types.sh ... failed
FAIL: 13 / 14 passed
Change-Id: Ia9d68c6b528c2b3a595ea6791c907374616d051f
Reviewed-on: https://chromium-review.googlesource.com/306682
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
diff --git a/futility/file_type_rwsig.c b/futility/file_type_rwsig.c
index e50ff32..b9c9e21 100644
--- a/futility/file_type_rwsig.c
+++ b/futility/file_type_rwsig.c
@@ -226,7 +226,8 @@
if (!vb2_verify_signature((const struct vb2_signature *)buf, len))
return FILE_TYPE_RWSIG;
- if (!vb2_verify_signature((const struct vb2_signature *)
+ if (len >= SIGNATURE_RSVD_SIZE &&
+ !vb2_verify_signature((const struct vb2_signature *)
(buf + len - SIGNATURE_RSVD_SIZE),
SIGNATURE_RSVD_SIZE))
return FILE_TYPE_RWSIG;
diff --git a/tests/futility/data/short_junk.bin b/tests/futility/data/short_junk.bin
new file mode 100644
index 0000000..dc765c3
--- /dev/null
+++ b/tests/futility/data/short_junk.bin
@@ -0,0 +1 @@
+JUNK
diff --git a/tests/futility/test_file_types.sh b/tests/futility/test_file_types.sh
index 8acbcf7..470d631 100755
--- a/tests/futility/test_file_types.sh
+++ b/tests/futility/test_file_types.sh
@@ -26,6 +26,7 @@
}
# Known types
+test_case "unknown" "tests/futility/data/short_junk.bin"
test_case "unknown" "tests/futility/data/random_noise.bin"
test_case "pubkey" "tests/devkeys/root_key.vbpubk"
test_case "keyblock" "tests/devkeys/kernel.keyblock"
