[pacman-dev] [PATCH] libalpm/signing.c: Fix calculation of packet size in parse_subpacket

Allan McRae allan at archlinux.org
Wed May 20 04:22:17 UTC 2020


Given RFC 4880 provides the code to do this calculation, I am not sure
how I managed to stuff that up!  This bug was only exposed when a
signature made with "include-key-block" was added to the Arch repos,
which provided a subpacket with the required size to hit this issue.

Signed-off-by: Allan McRae <allan at archlinux.org>
---

Also appropriate for 5.2.2

 lib/libalpm/signing.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/libalpm/signing.c b/lib/libalpm/signing.c
index c8eaaca2..422523b6 100644
--- a/lib/libalpm/signing.c
+++ b/lib/libalpm/signing.c
@@ -1058,7 +1058,7 @@ static int parse_subpacket(alpm_handle_t *handle, const char *identifier,
 				if(length_check(len, spos, 2, handle, identifier) != 0){
 					return -1;
 				}
-				slen = (sig[spos] << 8) | sig[spos + 1];
+				slen = (((sig[spos] - 192) << 8) | sig[spos + 1]) + 192;
 				spos = spos + 2;
 			} else {
 				if(length_check(len, spos, 5, handle, identifier) != 0) {
-- 
2.26.2


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