From 72b006f4bfd30b7c5037c163efaf279ab65bea9c Mon Sep 17 00:00:00 2001 From: Hans Jerry Illikainen Date: Wed, 27 Nov 2019 17:48:21 +0000 Subject: gpg-interface: prefer check_signature() for GPG verification MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This commit refactors the use of verify_signed_buffer() outside of gpg-interface.c to use check_signature() instead. It also turns verify_signed_buffer() into a file-local function since it's now only invoked internally by check_signature(). There were previously two globally scoped functions used in different parts of Git to perform GPG signature verification: verify_signed_buffer() and check_signature(). Now only check_signature() is used. The verify_signed_buffer() function doesn't guard against duplicate signatures as described by Michał Górny [1]. Instead it only ensures a non-erroneous exit code from GPG and the presence of at least one GOODSIG status field. This stands in contrast with check_signature() that returns an error if more than one signature is encountered. The lower degree of verification makes the use of verify_signed_buffer() problematic if callers don't parse and validate the various parts of the GPG status message themselves. And processing these messages seems like a task that should be reserved to gpg-interface.c with the function check_signature(). Furthermore, the use of verify_signed_buffer() makes it difficult to introduce new functionality that relies on the content of the GPG status lines. Now all operations that does signature verification share a single entry point to gpg-interface.c. This makes it easier to propagate changed or additional functionality in GPG signature verification to all parts of Git, without having odd edge-cases that don't perform the same degree of verification. [1] https://dev.gentoo.org/~mgorny/articles/attack-on-git-signature-verification.html Signed-off-by: Hans Jerry Illikainen Signed-off-by: Junio C Hamano --- gpg-interface.h | 9 --------- 1 file changed, 9 deletions(-) (limited to 'gpg-interface.h') diff --git a/gpg-interface.h b/gpg-interface.h index 3e624ec289..93cc3aff5c 100644 --- a/gpg-interface.h +++ b/gpg-interface.h @@ -46,15 +46,6 @@ size_t parse_signature(const char *buf, size_t size); int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key); -/* - * Run "gpg" to see if the payload matches the detached signature. - * gpg_output, when set, receives the diagnostic output from GPG. - * gpg_status, when set, receives the status output from GPG. - */ -int verify_signed_buffer(const char *payload, size_t payload_size, - const char *signature, size_t signature_size, - struct strbuf *gpg_output, struct strbuf *gpg_status); - int git_gpg_config(const char *, const char *, void *); void set_signing_key(const char *); const char *get_signing_key(void); -- cgit v1.2.3