Fallback to detached signatures during keyring check

Pacman has a 'key in keyring' verification step that makes sure the signatures
have a valid keyid. Currently pacman parses embedded package signatures only.

Add a fallback to detached signatures. If embedded signature is missing then it
tries to read corresponding *.sig file and get keyid from there.

Verification:
  debug: found cached pkg: /var/cache/pacman/pkg/glib-networking-2.64.3-1-x86_64.pkg.tar.zst
  debug: found detached signature /var/cache/pacman/pkg/glib-networking-2.64.3-1-x86_64.pkg.tar.zst.sig with size 310
  debug: found signature key: A5E9288C4FA415FA
  debug: looking up key A5E9288C4FA415FA locally
  debug: key lookup success, key exists

Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/libalpm/util.h b/lib/libalpm/util.h
index 4fc6e718..03c8ed44 100644
--- a/lib/libalpm/util.h
+++ b/lib/libalpm/util.h
@@ -155,6 +155,7 @@ int _alpm_fnmatch_patterns(alpm_list_t *patterns, const char *string);
 int _alpm_fnmatch(const void *pattern, const void *string);
 void *_alpm_realloc(void **data, size_t *current, const size_t required);
 void *_alpm_greedy_grow(void **data, size_t *current, const size_t required);
+alpm_errno_t _alpm_read_file(const char *filepath, unsigned char **data, size_t *data_len);
 
 #ifndef HAVE_STRSEP
 char *strsep(char **, const char *);