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-rw-r--r--lib/libalpm/signing.c178
1 files changed, 107 insertions, 71 deletions
diff --git a/lib/libalpm/signing.c b/lib/libalpm/signing.c
index 51b11df6..40c44f7f 100644
--- a/lib/libalpm/signing.c
+++ b/lib/libalpm/signing.c
@@ -999,6 +999,51 @@ static size_t length_check(size_t length, size_t position, size_t a,
}
}
+static int parse_subpacket(alpm_handle_t *handle, const char *identifier,
+ const unsigned char *sig, const size_t len, const size_t pos,
+ const size_t plen, alpm_list_t **keys)
+{
+ size_t slen;
+ size_t spos = pos;
+
+ while(spos < pos + plen) {
+ if(sig[spos] < 192) {
+ slen = sig[spos];
+ spos = spos + 1;
+ } else if(sig[spos] < 255) {
+ if(length_check(len, spos, 2, handle, identifier) != 0){
+ return -1;
+ }
+ slen = (sig[spos] << 8) | sig[spos + 1];
+ spos = spos + 2;
+ } else {
+ if(length_check(len, spos, 5, handle, identifier) != 0) {
+ return -1;
+ }
+ slen = (sig[spos + 1] << 24) | (sig[spos + 2] << 16) | (sig[spos + 3] << 8) | sig[spos + 4];
+ spos = spos + 5;
+ }
+ if(sig[spos] == 16) {
+ /* issuer key ID */
+ char key[17];
+ size_t i;
+ if(length_check(len, spos, 8, handle, identifier) != 0) {
+ return -1;
+ }
+ for (i = 0; i < 8; i++) {
+ sprintf(&key[i * 2], "%02X", sig[spos + i + 1]);
+ }
+ *keys = alpm_list_add(*keys, strdup(key));
+ break;
+ }
+ if(length_check(len, spos, slen, handle, identifier) != 0) {
+ return -1;
+ }
+ spos = spos + slen;
+ }
+ return 0;
+}
+
/**
* Extract the Issuer Key ID from a signature
* @param sig PGP signature
@@ -1009,7 +1054,7 @@ static size_t length_check(size_t length, size_t position, size_t a,
int SYMEXPORT alpm_extract_keyid(alpm_handle_t *handle, const char *identifier,
const unsigned char *sig, const size_t len, alpm_list_t **keys)
{
- size_t pos, spos, blen, hlen, ulen, slen;
+ size_t pos, blen, hlen, ulen;
pos = 0;
while(pos < len) {
@@ -1020,49 +1065,69 @@ int SYMEXPORT alpm_extract_keyid(alpm_handle_t *handle, const char *identifier,
}
if(sig[pos] & 0x40) {
- /* "new" packet format is not supported */
- _alpm_log(handle, ALPM_LOG_ERROR,
- _("%s: unsupported signature format\n"), identifier);
- return -1;
- }
-
- if(((sig[pos] & 0x3f) >> 2) != 2) {
- /* signature is not a "Signature Packet" */
- _alpm_log(handle, ALPM_LOG_ERROR,
- _("%s: signature format error\n"), identifier);
- return -1;
- }
+ /* new packet format */
+ if(length_check(len, pos, 1, handle, identifier) != 0) {
+ return -1;
+ }
+ pos = pos + 1;
- switch(sig[pos] & 0x03) {
- case 0:
- if(length_check(len, pos, 2, handle, identifier) != 0) {
+ if(sig[pos] < 192) {
+ if(length_check(len, pos, 1, handle, identifier) != 0) {
return -1;
}
- blen = sig[pos + 1];
- pos = pos + 2;
- break;
-
- case 1:
- if(length_check(len, pos, 3, handle, identifier)) {
+ blen = sig[pos];
+ pos = pos + 1;
+ } else if (sig[pos] < 224) {
+ if(length_check(len, pos, 2, handle, identifier) != 0) {
return -1;
}
- blen = (sig[pos + 1] << 8) | sig[pos + 2];
- pos = pos + 3;
- break;
-
- case 2:
+ blen = ((sig[pos] - 192) << 8) + sig[pos + 1] + 192;
+ pos = pos + 2;
+ } else if (sig[pos] == 255) {
if(length_check(len, pos, 5, handle, identifier)) {
return -1;
}
blen = (sig[pos + 1] << 24) | (sig[pos + 2] << 16) | (sig[pos + 3] << 8) | sig[pos + 4];
pos = pos + 5;
- break;
-
- case 3:
+ } else {
/* partial body length not supported */
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: unsupported signature format\n"), identifier);
return -1;
+ }
+ } else {
+ /* old package format */
+ switch(sig[pos] & 0x03) {
+ case 0:
+ if(length_check(len, pos, 2, handle, identifier) != 0) {
+ return -1;
+ }
+ blen = sig[pos + 1];
+ pos = pos + 2;
+ break;
+
+ case 1:
+ if(length_check(len, pos, 3, handle, identifier) != 0) {
+ return -1;
+ }
+ blen = (sig[pos + 1] << 8) | sig[pos + 2];
+ pos = pos + 3;
+ break;
+
+ case 2:
+ if(length_check(len, pos, 5, handle, identifier) != 0) {
+ return -1;
+ }
+ blen = (sig[pos + 1] << 24) | (sig[pos + 2] << 16) | (sig[pos + 3] << 8) | sig[pos + 4];
+ pos = pos + 5;
+ break;
+
+ case 3:
+ /* partial body length not supported */
+ _alpm_log(handle, ALPM_LOG_ERROR,
+ _("%s: unsupported signature format\n"), identifier);
+ return -1;
+ }
}
if(sig[pos] != 4) {
@@ -1071,14 +1136,12 @@ int SYMEXPORT alpm_extract_keyid(alpm_handle_t *handle, const char *identifier,
_("%s: unsupported signature format\n"), identifier);
return -1;
}
-
if(sig[pos + 1] != 0x00) {
/* not a signature of a binary document */
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature format error\n"), identifier);
return -1;
}
-
pos = pos + 4;
/* pos got changed above, so an explicit check is necessary
@@ -1087,55 +1150,28 @@ int SYMEXPORT alpm_extract_keyid(alpm_handle_t *handle, const char *identifier,
return -1;
}
hlen = (sig[pos] << 8) | sig[pos + 1];
+ if(length_check(len, pos, hlen + 2, handle, identifier) != 0) {
+ return -1;
+ }
+ pos = pos + 2;
- if(length_check(len, pos, hlen + 2, handle, identifier)) {
+ if(parse_subpacket(handle, identifier, sig, len, pos, hlen, keys) == -1) {
return -1;
}
- pos = pos + hlen + 2;
+ pos = pos + hlen;
ulen = (sig[pos] << 8) | sig[pos + 1];
+ if(length_check(len, pos, ulen + 2, handle, identifier) != 0) {
+ return -1;
+ }
pos = pos + 2;
- spos = pos;
-
- while(spos < pos + ulen) {
- if(sig[spos] < 192) {
- slen = sig[spos];
- spos = spos + 1;
- } else if(sig[spos] < 255) {
- if(length_check(pos + ulen, spos, 2, handle, identifier)){
- return -1;
- }
- slen = (sig[spos] << 8) | sig[spos + 1];
- spos = spos + 2;
- } else {
- /* check for pos and spos, as spos is still pos */
- if(length_check(len, pos, 5, handle, identifier)) {
- return -1;
- }
- slen = (sig[spos + 1] << 24) | (sig[spos + 2] << 16) | (sig[spos + 3] << 8) | sig[spos + 4];
- spos = spos + 5;
- }
- if(sig[spos] == 16) {
- /* issuer key ID */
- char key[17];
- size_t i;
- if(length_check(pos + ulen, spos, 8, handle, identifier)) {
- return -1;
- }
- for (i = 0; i < 8; i++) {
- sprintf(&key[i * 2], "%02X", sig[spos + i + 1]);
- }
- *keys = alpm_list_add(*keys, strdup(key));
- break;
- }
- if(length_check(pos + ulen + 1, spos, slen, handle, identifier)) {
- return -1;
- }
- spos = spos + slen;
+ if(parse_subpacket(handle, identifier, sig, len, pos, ulen, keys) == -1) {
+ return -1;
}
pos = pos + (blen - hlen - 8);
}
+
return 0;
}

Copyright © 2002-2022 Judd Vinet and Aaron Griffin. Copyright © 2022 Erich Eckner.
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