72b006f4bf
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 <hji@dyntopia.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
#ifndef GPG_INTERFACE_H
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#define GPG_INTERFACE_H
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struct strbuf;
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#define GPG_VERIFY_VERBOSE 1
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#define GPG_VERIFY_RAW 2
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#define GPG_VERIFY_OMIT_STATUS 4
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struct signature_check {
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char *payload;
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char *gpg_output;
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char *gpg_status;
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/*
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* possible "result":
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* 0 (not checked)
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* N (checked but no further result)
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* U (untrusted good)
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* G (good)
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* B (bad)
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*/
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char result;
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char *signer;
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char *key;
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char *fingerprint;
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char *primary_key_fingerprint;
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};
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void signature_check_clear(struct signature_check *sigc);
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/*
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* Look at GPG signed content (e.g. a signed tag object), whose
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* payload is followed by a detached signature on it. Return the
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* offset where the embedded detached signature begins, or the end of
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* the data when there is no such signature.
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*/
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size_t parse_signature(const char *buf, size_t size);
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/*
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* Create a detached signature for the contents of "buffer" and append
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* it after "signature"; "buffer" and "signature" can be the same
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* strbuf instance, which would cause the detached signature appended
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* at the end.
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*/
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int sign_buffer(struct strbuf *buffer, struct strbuf *signature,
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const char *signing_key);
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int git_gpg_config(const char *, const char *, void *);
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void set_signing_key(const char *);
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const char *get_signing_key(void);
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int check_signature(const char *payload, size_t plen,
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const char *signature, size_t slen,
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struct signature_check *sigc);
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void print_signature_buffer(const struct signature_check *sigc,
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unsigned flags);
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#endif
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