diff --git a/mail/exim/patches/000-preliminary-fixes-for-ZDI-vulns.patch b/mail/exim/patches/000-preliminary-fixes-for-ZDI-vulns.patch new file mode 100644 index 0000000000..fee68a2419 --- /dev/null +++ b/mail/exim/patches/000-preliminary-fixes-for-ZDI-vulns.patch @@ -0,0 +1,185 @@ +From florz@florz.de Sun Oct 1 10:33:31 2023 +Received: from [10.0.0.9] (helo=cumin.exim.org) + by mailman with esmtp (Exim 4.94.2) + (envelope-from ) + id 1qmspP-003gpc-28 + for exim-dev@lists.exim.org; Sun, 01 Oct 2023 09:33:31 +0000 +Authentication-Results: exim.org; + iprev=pass (rain.florz.de) smtp.remote-ip=2a07:12c0:1c00:40::1; + dmarc=none header.from=florz.de; + arc=none +Received: from rain.florz.de ([2a07:12c0:1c00:40::1]:36467) + by cumin.exim.org with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 + (Exim 4.94.2-31-503e55a2c) + (envelope-from ) + id 1qmspN-00EIpR-5w + for exim-dev@lists.exim.org; Sun, 01 Oct 2023 09:33:30 +0000 +Received: from [2a07:12c0:1c00:43::121] (port=60772 helo=florz.florz.de) + by rain.florz.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) + (Exim 4.92) + (envelope-from ) + id 1qmspL-0007Zj-F8 + for exim-dev@lists.exim.org; Sun, 01 Oct 2023 11:33:27 +0200 +Received: from florz by florz.florz.de with local (Exim 4.92) + (envelope-from ) + id 1qmspK-0001ZU-Sl + for exim-dev@lists.exim.org; Sun, 01 Oct 2023 11:33:26 +0200 +Date: Sun, 1 Oct 2023 11:33:26 +0200 +From: Florian Zumbiehl +To: exim-dev@lists.exim.org +Message-ID: <20231001093326.GS3837@florz.florz.de> +MIME-Version: 1.0 +Content-Type: text/plain; charset=us-ascii +Content-Disposition: inline +User-Agent: Mutt/1.10.1 (2018-07-13) +X-Spam-Score: 0.0 (/) +Message-ID-Hash: D3TCMSGJTLM76H6APEQXZEYOLYJKKCNZ +X-Message-ID-Hash: D3TCMSGJTLM76H6APEQXZEYOLYJKKCNZ +X-MailFrom: florz@florz.de +X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-config-1; header-match-exim-dev.lists.exim.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header +X-Mailman-Version: 3.3.3 +Precedence: list +Subject: [exim-dev] Hotfix for some of the ZDI vulnerabilities +List-Id: Exim MTA development list +List-Help: +List-Owner: +List-Post: +List-Subscribe: +List-Unsubscribe: +Message: 1 +Status: RO +Content-Length: 5347 + +Hi, + +below you find a patch that fixes some (probably three?) of what I guess are +the vulnerabilities reported by ZDI. + +Please note that the patch is only mildly tested, it is developed based on +the git master branch, but can be applied to older versions with minor +massaging. If you go back far enough, proxy.c was part of smtp_in.c, but if +you adjust for that, the patch can be made to apply there, too. + +Obviously, I have no idea whether this actually addresses what ZDI has +reported, but if not, these probably should be fixed, too, and if so, given +the fact that I managed to rather easily find these vulnerabilities based +on the information that's publicly available, I don't think there is much +point to trying to keep this secret any longer--if anything, it's +counterproductive. + +Also mind you that this is a hot fix, it's neither elegant, nor does it do +any useful error reporting, the goal was simply to prevent out of bounds +accesses. + +Florian + +--- + +--- a/src/auths/external.c ++++ b/src/auths/external.c +@@ -100,6 +100,9 @@ if (expand_nmax == 0) /* skip if rxd da + if ((rc = auth_prompt(CUS"")) != OK) + return rc; + ++if (expand_nmax != 1) ++ return FAIL; ++ + if (ob->server_param2) + { + uschar * s = expand_string(ob->server_param2); +--- a/src/auths/spa.c ++++ b/src/auths/spa.c +@@ -165,12 +165,18 @@ if (auth_get_no64_data(&data, msgbuf) != + return FAIL; + + /* dump client response */ +-if (spa_base64_to_bits(CS &response, sizeof(response), CCS data) < 0) ++int l = spa_base64_to_bits(CS &response, sizeof(response), CCS data); ++if (l < 0) + { + DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " + "response: %s\n", data); + return FAIL; + } ++if(l < (char *)&response.buffer - (char *)&response)return FAIL; ++unsigned long o = IVAL(&response.uUser.offset, 0); ++if((l < o) || (l - o < SVAL(&response.uUser.len, 0)))return FAIL; ++o = IVAL(&response.ntResponse.offset, 0); ++if((l < o) || (l - o < 24))return FAIL; + + /*************************************************************** + PH 07-Aug-2003: The original code here was this: +@@ -345,7 +351,10 @@ if (!smtp_read_response(sx, US buffer, b + + /* convert the challenge into the challenge struct */ + DSPA("\n\n%s authenticator: challenge (%s)\n\n", ablock->name, buffer + 4); +-spa_base64_to_bits(CS (&challenge), sizeof(challenge), CCS (buffer + 4)); ++int l = spa_base64_to_bits(CS (&challenge), sizeof(challenge), CCS (buffer + 4)); ++if((l < 0) || (l < (char *)&challenge.buffer - (char *)&challenge))return FAIL; ++unsigned long o = IVAL(&challenge.uDomain.offset, 0); ++if((l < o) || (l - o < SVAL(&challenge.uDomain.len, 0)))return FAIL; + + spa_build_auth_response(&challenge, &response, CS username, CS password); + spa_bits_to_base64(US msgbuf, US &response, spa_request_length(&response)); +--- a/src/smtp_in.c ++++ b/src/smtp_in.c +@@ -1172,6 +1172,8 @@ while (capacity > 0) + do { ret = read(fd, to, 1); } while (ret == -1 && errno == EINTR && !had_command_timeout); + if (ret == -1) + return -1; ++ if (!ret) ++ break; + have++; + if (last) + return have; +@@ -1320,6 +1322,8 @@ if ((ret == PROXY_INITIAL_READ) && (memc + goto proxyfail; + } + ++ if (ret < 16) ++ goto proxyfail; + /* The v2 header will always be 16 bytes per the spec. */ + size = 16 + ntohs(hdr.v2.len); + DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n", +@@ -1340,7 +1344,7 @@ if ((ret == PROXY_INITIAL_READ) && (memc + { + retmore = read(fd, (uschar*)&hdr + ret, size-ret); + } while (retmore == -1 && errno == EINTR && !had_command_timeout); +- if (retmore == -1) ++ if (retmore < 1) + goto proxyfail; + ret += retmore; + DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size); +@@ -1362,6 +1366,8 @@ if (ret >= 16 && memcmp(&hdr.v2, v2sig, + switch (hdr.v2.fam) + { + case 0x11: /* TCPv4 address type */ ++ if (ret < 28) ++ goto proxyfail; + iptype = US"IPv4"; + tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr; + inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip)); +@@ -1388,6 +1394,8 @@ if (ret >= 16 && memcmp(&hdr.v2, v2sig, + proxy_external_port = tmpport; + goto done; + case 0x21: /* TCPv6 address type */ ++ if (ret < 52) ++ goto proxyfail; + iptype = US"IPv6"; + memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16); + inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6)); +@@ -1446,10 +1454,13 @@ else if (ret >= 8 && memcmp(hdr.v1.line, + goto proxyfail; + ret += r2; + ++ if(ret > 107) ++ goto proxyfail; ++ hdr.v1.line[ret] = 0; + p = string_copy(hdr.v1.line); + end = memchr(p, '\r', ret - 1); + +- if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n') ++ if (!end || end[1] != '\n') + { + DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n"); + goto proxyfail;