From 54ea136fded56810bf475885eb4bd7bf1b11f09c Mon Sep 17 00:00:00 2001 From: Tianjie Xu Date: Fri, 16 Dec 2016 16:24:09 -0800 Subject: [PATCH] Add a checker for signature boundary in verifier The 'signature_start' variable marks the location of the signature from the end of a zip archive. And a boundary check is missing where 'signature_start' should be within the EOCD comment field. This causes problems when sideloading a malicious package. Also add a corresponding test. Bug: 31914369 Test: Verification fails correctly when sideloading recovery_test.zip on angler. Change-Id: I6ea96bf04dac5d8d4d6719e678d504f957b4d5c1 (cherry-picked from f69e6a9475983b2ad46729e44ab58d2b22cd74d0) --- verifier.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/verifier.cpp b/verifier.cpp index eeff95a5..3d4f603a 100644 --- a/verifier.cpp +++ b/verifier.cpp @@ -143,6 +143,12 @@ int verify_file(unsigned char* addr, size_t length, LOGI("comment is %zu bytes; signature %zu bytes from end\n", comment_size, signature_start); + if (signature_start > comment_size) { + LOGE("signature start: %zu is larger than comment size: %zu\n", signature_start, + comment_size); + return VERIFY_FAILURE; + } + if (signature_start <= FOOTER_SIZE) { LOGE("Signature start is in the footer"); return VERIFY_FAILURE;