From: Jonathan McDowell <noodles@earth.li>
Date: Sun, 29 Sep 2013 21:12:21 +0000 (+0100)
Subject: Prevent read_openpgp_stream from returning empty packets
X-Git-Url: https://git.sommitrealweird.co.uk/onak.git/commitdiff_plain/4b48bfe2bb8471be547a0503aa516a5248277bac?ds=inline;hp=f0a63a7442a69bd08130efcb03d5e4b18110b859

Prevent read_openpgp_stream from returning empty packets

If read_openpgp_stream got an invalid packet that had a semi valid
header it could potentially return an empty package, which would
confuse splitkeys. Cleanup the final package returned if it turns
out we didn't have valid data for it.

Fixes Debian bug #716350
---

diff --git a/parsekey.c b/parsekey.c
index aedbd14..b8bb5b0 100644
--- a/parsekey.c
+++ b/parsekey.c
@@ -191,7 +191,7 @@ onak_status_t read_openpgp_stream(int (*getchar_func)(void *ctx, size_t count,
 				int maxnum)
 {
 	unsigned char			 curchar = 0;
-	struct openpgp_packet_list	*curpacket = NULL;
+	struct openpgp_packet_list	*curpacket = NULL, **packetend = NULL;
 	onak_status_t			 rc = ONAK_E_OK;
 	int				 keys = 0;
 	bool				 inpacket = false;
@@ -216,10 +216,12 @@ onak_status_t read_openpgp_stream(int (*getchar_func)(void *ctx, size_t count,
 			inpacket = true;
 			if (curpacket != NULL) {
 				curpacket->next = malloc(sizeof (*curpacket));
+				packetend = &curpacket->next;
 				curpacket = curpacket->next;
 			} else {
 				*packets = curpacket =
 					malloc(sizeof (*curpacket));
+				packetend = packets;
 			}
 			memset(curpacket, 0, sizeof(*curpacket));
 			curpacket->packet =
@@ -245,7 +247,9 @@ onak_status_t read_openpgp_stream(int (*getchar_func)(void *ctx, size_t count,
 					curpacket->packet->length += 192;
 				} else if (curpacket->packet->length > 223 &&
 					curpacket->packet->length < 255) {
-					return ONAK_E_UNSUPPORTED_FEATURE;
+					free(curpacket->packet);
+					curpacket->packet = NULL;
+					rc = ONAK_E_UNSUPPORTED_FEATURE;
 				} else if (curpacket->packet->length == 255) {
 					/*
 					 * 5 byte length; ie 255 followed by 3
@@ -292,8 +296,8 @@ onak_status_t read_openpgp_stream(int (*getchar_func)(void *ctx, size_t count,
 					break;
 				case 3:
 					rc = ONAK_E_UNSUPPORTED_FEATURE;
-					curpacket->packet->length = 0;
-					curpacket->packet->data = NULL;
+					free(curpacket->packet);
+					curpacket->packet = NULL;
 					break;
 				}
 			}
@@ -320,6 +324,12 @@ onak_status_t read_openpgp_stream(int (*getchar_func)(void *ctx, size_t count,
 		}
 	}
 
+	/* Trim the last packet if it doesn't actually exist */
+	if (packetend != NULL && (*packetend)->packet == NULL) {
+		free(*packetend);
+		*packetend = NULL;
+	}
+
 	return (rc);
 }
 
diff --git a/splitkeys.c b/splitkeys.c
index 2d3c58c..2a91d2f 100644
--- a/splitkeys.c
+++ b/splitkeys.c
@@ -63,7 +63,7 @@ int main(int argc, char *argv[])
 					tmp->next = NULL;
 				}
 			}
-			if (tmp->next != NULL) {
+			if (tmp != NULL && tmp->next != NULL) {
 				list_end = NULL;
 			}