[PATCH] configure: Ensure that GMime can extract session keys

[PATCH] configure: Ensure that GMime can extract session keys

[Daniel Kahn Gillmor]

GMime 3.0 and higher can extract session keys, but it will *not*
extract session keys if it was built with --disable-crypto, or if it
was built against GPGME version < 1.8.0.

Notmuch currently expects to be able to extract session keys, and
tests will fail if it is not possible, so we ensure that this is the
case during ./configure time.

Part of this feels awkward because notmuch doesn't directly depend on
gpg at all.  Rather, it depends on GMime, and the current
implementation of GMime depends on GPGME for its crypto, and GPGME in
turn depends on gpg.

So the use of gpg in ./configure isn't actually introducing a new
dependency, though if a future version of GMime were ever to move away
from GnuPG, we might need to reconsider.

Note that this changeset depends on
id:20190506174327.13457-1-dkg@fifthhorseman.net , which supplies the
rfc822 message test/corpora/crypto/basic-encrypted.eml used in it.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---
 configure | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/configure b/configure
index 9140026a..805292be 100755
--- a/configure
+++ b/configure
@@ -497,6 +497,60 @@ if pkg-config --exists "gmime-3.0 > $GMIME_MINVER"; then
     have_gmime=1
     gmime_cflags=$(pkg-config --cflags gmime-3.0)
     gmime_ldflags=$(pkg-config --libs gmime-3.0)
+
+    printf "Checking for GMime session key extraction support... "
+
+    cat > _check_session_keys.c <<EOF
+#include <gmime/gmime.h>
+#include <stdio.h>
+
+int main () {
+    GError *error = NULL;
+    GMimeParser *parser = NULL;
+    GMimeMultipartEncrypted *body = NULL;
+    GMimeDecryptResult *decrypt_result = NULL;
+    GMimeObject *output = NULL;
+
+    g_mime_init ();
+    parser = g_mime_parser_new ();
+    g_mime_parser_init_with_stream (parser, g_mime_stream_file_open("test/corpora/crypto/basic-encrypted.eml", "r", &error));
+    if (error) return !! fprintf (stderr, "failed to instantiate parser with test/corpora/crypto/basic-encrypted.eml\n");
+
+    body = GMIME_MULTIPART_ENCRYPTED(g_mime_message_get_mime_part (g_mime_parser_construct_message (parser, NULL)));
+    if (body == NULL) return !!	fprintf (stderr, "did not find a multipart encrypted message\n");
+
+    output = g_mime_multipart_encrypted_decrypt (body, GMIME_DECRYPT_EXPORT_SESSION_KEY, NULL, &decrypt_result, &error);
+    if (error || output == NULL) return !! fprintf (stderr, "decryption failed\n");
+
+    if (decrypt_result == NULL) return !! fprintf (stderr, "no GMimeDecryptResult found\n");
+    if (decrypt_result->session_key == NULL) return !! fprintf (stderr, "GMimeDecryptResult has no session key\n");
+
+    printf ("%s\n", decrypt_result->session_key);
+    return 0;
+}
+EOF
+    if ${CC} ${CFLAGS} ${gmime_cflags} ${gmime_ldflags}  _check_session_keys.c -o _check_session_keys > /dev/null 2>&1 \
+           && TEMP_GPG=$(mktemp -d) \
+           && GNUPGHOME=${TEMP_GPG} gpg --batch --quiet --import < test/gnupg-secret-key.asc \
+           && SESSION_KEY=$(./_check_session_keys) \
+           && [ $SESSION_KEY = 9:0BACD64099D1468AB07C796F0C0AC4851948A658A15B34E803865E9FC635F2F5 ]
+    then
+        printf "OK.\n"
+    else
+        cat <<EOF
+
+*** Error: Could not extract session keys from encrypted message.
+
+This is likely due to your GMime having been built against a old
+version of GPGME.
+
+Please try to rebuild your version of GMime against a more recent
+version of GPGME (at least GPGME 1.8.0).  Your current GPGME version
+is: $(gpgme-config --version)
+EOF
+        rm -rf _check_session_keys.c _check_session_keys "$TEMP_GPG"
+        errors=$((errors + 1))
+    fi
 else
     have_gmime=0
     printf "No.\n"
-- 
2.20.1

[PATCH v2] configure: Ensure that GMime can extract session keys

[Daniel Kahn Gillmor]

GMime 3.0 and higher can extract session keys, but it will *not*
extract session keys if it was built with --disable-crypto, or if it
was built against GPGME version < 1.8.0.

Notmuch currently expects to be able to extract session keys, and
tests will fail if it is not possible, so we ensure that this is the
case during ./configure time.

Part of this feels awkward because notmuch doesn't directly depend on
gpg at all.  Rather, it depends on GMime, and the current
implementation of GMime depends on GPGME for its crypto, and GPGME in
turn depends on gpg.

So the use of gpg in ./configure isn't actually introducing a new
dependency, though if a future version of GMime were ever to move away
from GnuPG, we might need to reconsider.

Note that this changeset depends on
id:20190506174327.13457-1-dkg@fifthhorseman.net , which supplies the
rfc822 message test/corpora/crypto/basic-encrypted.eml used in it.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---
 configure | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/configure b/configure
index 9140026a..e157aadf 100755
--- a/configure
+++ b/configure
@@ -497,6 +497,60 @@ if pkg-config --exists "gmime-3.0 > $GMIME_MINVER"; then
     have_gmime=1
     gmime_cflags=$(pkg-config --cflags gmime-3.0)
     gmime_ldflags=$(pkg-config --libs gmime-3.0)
+
+    printf "Checking for GMime session key extraction support... "
+
+    cat > _check_session_keys.c <<EOF
+#include <gmime/gmime.h>
+#include <stdio.h>
+
+int main () {
+    GError *error = NULL;
+    GMimeParser *parser = NULL;
+    GMimeMultipartEncrypted *body = NULL;
+    GMimeDecryptResult *decrypt_result = NULL;
+    GMimeObject *output = NULL;
+
+    g_mime_init ();
+    parser = g_mime_parser_new ();
+    g_mime_parser_init_with_stream (parser, g_mime_stream_file_open("test/corpora/crypto/basic-encrypted.eml", "r", &error));
+    if (error) return !! fprintf (stderr, "failed to instantiate parser with test/corpora/crypto/basic-encrypted.eml\n");
+
+    body = GMIME_MULTIPART_ENCRYPTED(g_mime_message_get_mime_part (g_mime_parser_construct_message (parser, NULL)));
+    if (body == NULL) return !!	fprintf (stderr, "did not find a multipart encrypted message\n");
+
+    output = g_mime_multipart_encrypted_decrypt (body, GMIME_DECRYPT_EXPORT_SESSION_KEY, NULL, &decrypt_result, &error);
+    if (error || output == NULL) return !! fprintf (stderr, "decryption failed\n");
+
+    if (decrypt_result == NULL) return !! fprintf (stderr, "no GMimeDecryptResult found\n");
+    if (decrypt_result->session_key == NULL) return !! fprintf (stderr, "GMimeDecryptResult has no session key\n");
+
+    printf ("%s\n", decrypt_result->session_key);
+    return 0;
+}
+EOF
+    if ${CC} ${CFLAGS} ${gmime_cflags} ${gmime_ldflags}  _check_session_keys.c -o _check_session_keys > /dev/null 2>&1 \
+           && TEMP_GPG=$(mktemp -d) \
+           && GNUPGHOME=${TEMP_GPG} gpg --batch --quiet --import < test/gnupg-secret-key.asc \
+           && SESSION_KEY=$(GNUPGHOME=${TEMP_GPG} ./_check_session_keys) \
+           && [ $SESSION_KEY = 9:0BACD64099D1468AB07C796F0C0AC4851948A658A15B34E803865E9FC635F2F5 ]
+    then
+        printf "OK.\n"
+    else
+        cat <<EOF
+
+*** Error: Could not extract session keys from encrypted message.
+
+This is likely due to your GMime having been built against a old
+version of GPGME.
+
+Please try to rebuild your version of GMime against a more recent
+version of GPGME (at least GPGME 1.8.0).  Your current GPGME version
+is: $(gpgme-config --version)
+EOF
+        rm -rf _check_session_keys.c _check_session_keys "$TEMP_GPG"
+        errors=$((errors + 1))
+    fi
 else
     have_gmime=0
     printf "No.\n"
-- 
2.20.1

Re: [PATCH v2] configure: Ensure that GMime can extract session keys

[Daniel Kahn Gillmor]

[-- Attachment #1: Type: text/plain, Size: 712 bytes --]

On Mon 2019-05-06 16:16:55 -0400, Daniel Kahn Gillmor wrote:
> GMime 3.0 and higher can extract session keys, but it will *not*
> extract session keys if it was built with --disable-crypto, or if it
> was built against GPGME version < 1.8.0.
>
> Notmuch currently expects to be able to extract session keys, and
> tests will fail if it is not possible, so we ensure that this is the
> case during ./configure time.

please consider v2 of this -- my initial sent draft only worked by
accident due to a malingering GnuPG homedir, bc i'd forgotten to set
GNUPGHOME in this line:

> +           && SESSION_KEY=$(GNUPGHOME=${TEMP_GPG} ./_check_session_keys) \

v2 handles it just fine, sorry for the noise.

   --dkg

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Re: [PATCH v2] configure: Ensure that GMime can extract session keys

[Daniel Kahn Gillmor]

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On Mon 2019-05-06 16:16:55 -0400, Daniel Kahn Gillmor wrote:
> GMime 3.0 and higher can extract session keys, but it will *not*
> extract session keys if it was built with --disable-crypto, or if it
> was built against GPGME version < 1.8.0.
>
> Notmuch currently expects to be able to extract session keys, and
> tests will fail if it is not possible, so we ensure that this is the
> case during ./configure time.

It would be great to see this patch merged -- it sets up a
./configure-time test to ensure that notmuch can indeed deal with
session keys correctly, which is necessary for the test suite to pass
(and for notmuch to offer sensible decryption and cleartext-indexing
options.

If there's some reason to not merge it, please let me know.  All of its
dependencies have been merged.

     --dkg

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Re: [PATCH v2] configure: Ensure that GMime can extract session keys

[David Bremner]

Daniel Kahn Gillmor <dkg@fifthhorseman.net> writes:

> GMime 3.0 and higher can extract session keys, but it will *not*
> extract session keys if it was built with --disable-crypto, or if it
> was built against GPGME version < 1.8.0.
>
> Notmuch currently expects to be able to extract session keys, and
> tests will fail if it is not possible, so we ensure that this is the
> case during ./configure time.
>
> Part of this feels awkward because notmuch doesn't directly depend on
> gpg at all.  Rather, it depends on GMime, and the current
> implementation of GMime depends on GPGME for its crypto, and GPGME in
> turn depends on gpg.
>
> So the use of gpg in ./configure isn't actually introducing a new
> dependency, though if a future version of GMime were ever to move away
> from GnuPG, we might need to reconsider.
>
> Note that this changeset depends on
> id:20190506174327.13457-1-dkg@fifthhorseman.net , which supplies the
> rfc822 message test/corpora/crypto/basic-encrypted.eml used in it.
>

I pushed this, and broke travis. Can you please have a look at

  https://travis-ci.org/notmuch/notmuch/builds/534979532

d

Re: [PATCH v2] configure: Ensure that GMime can extract session keys

[Daniel Kahn Gillmor]

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On Mon 2019-05-20 16:46:23 -0300, David Bremner wrote:
> I pushed this, and broke travis. Can you please have a look at
>
>   https://travis-ci.org/notmuch/notmuch/builds/534979532

Sorry about this, the flaw was a difference between the ubuntu and
debian linker default behavior.

I've responded over at id:20190520205201.12883-1-dkg@fifthhorseman.net

     --dkg


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