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Diffstat (limited to 'meta-networking/recipes-daemons/postfix/files/CVE-2023-51764-2.patch')
| -rw-r--r-- | meta-networking/recipes-daemons/postfix/files/CVE-2023-51764-2.patch | 978 |
1 files changed, 978 insertions, 0 deletions
diff --git a/meta-networking/recipes-daemons/postfix/files/CVE-2023-51764-2.patch b/meta-networking/recipes-daemons/postfix/files/CVE-2023-51764-2.patch new file mode 100644 index 0000000000..e97a088557 --- /dev/null +++ b/meta-networking/recipes-daemons/postfix/files/CVE-2023-51764-2.patch @@ -0,0 +1,978 @@ +From cb3b1cbda3dec086a7f4541fe64751d9bb2988bd Mon Sep 17 00:00:00 2001 +From: Wietse Venema <wietse@porcupine.org> +Date: Sun, 21 Jan 2024 00:00:00 -0500 +Subject: [PATCH] postfix-3.6.14 + +--- + +Upstream-Status: Backport from [https://launchpad.net/ubuntu/+source/postfix/3.6.4-1ubuntu1.3] +CVE: CVE-2023-51764 +Signed-off-by: Ashish Sharma <asharma@mvista.com> + + man/man5/postconf.5 | 173 +++++++++++++++++++++++++++++++++++------- + man/man8/cleanup.8 | 8 + + man/man8/smtpd.8 | 11 +- + mantools/postlink | 6 - + proto/postconf.proto | 142 +++++++++++++++++++++++++++------- + src/cleanup/cleanup.c | 8 + + src/cleanup/cleanup_init.c | 2 + src/cleanup/cleanup_message.c | 17 ++++ + src/global/cleanup_strerror.c | 1 + src/global/cleanup_user.h | 6 + + src/global/mail_params.h | 9 +- + src/global/smtp_stream.c | 34 +++++--- + src/global/smtp_stream.h | 4 + src/smtpd/smtpd.c | 114 ++++++++++++++++++++------- + src/smtpd/smtpd_check.c | 14 ++- + src/smtpd/smtpd_check.h | 1 + 16 files changed, 443 insertions(+), 107 deletions(-) + +--- a/man/man5/postconf.5 ++++ b/man/man5/postconf.5 +@@ -845,6 +845,32 @@ + .fi + .ad + .ft R ++.SH cleanup_replace_stray_cr_lf (default: yes) ++Replace each stray <CR> or <LF> character in message ++content with a space character, to prevent outbound SMTP smuggling, ++and to make the evaluation of Postfix\-added DKIM or other signatures ++independent from how a remote mail server handles such characters. ++.PP ++SMTP does not allow such characters unless they are part of a ++<CR><LF> sequence, and different mail systems handle ++such stray characters in an implementation\-dependent manner. Stray ++<CR> or <LF> characters could be used for outbound ++SMTP smuggling, where an attacker uses a Postfix server to send ++message content with a non\-standard End\-of\-DATA sequence that ++triggers inbound SMTP smuggling at a remote SMTP server. ++.PP ++The replacement happens before all other content management, ++and before Postfix may add a DKIM etc. signature; if the signature ++were created first, the replacement could invalidate the signature. ++.PP ++In addition to preventing SMTP smuggling, replacing stray ++<CR> or <LF> characters ensures that the result of ++signature validation by later mail system will not depend on how ++that mail system handles those stray characters in an ++implementation\-dependent manner. ++.PP ++This feature is available in Postfix >= 3.9, 3.8.5, 3.7.10, ++3.6.14, and 3.5.24. + .SH cleanup_service_name (default: cleanup) + The name of the \fBcleanup\fR(8) service. This service rewrites addresses + into the standard form, and performs \fBcanonical\fR(5) address mapping +@@ -10413,60 +10439,153 @@ + .PP + This feature is available in Postfix 2.0 and later. + .SH smtpd_forbid_bare_newline (default: Postfix < 3.9: no) +-Reply with "Error: bare <LF> received" and disconnect +-when a remote SMTP client sends a line ending in <LF>, violating +-the RFC 5321 requirement that lines must end in <CR><LF>. +-This feature is disbled by default with Postfix < 3.9. Use +-smtpd_forbid_bare_newline_exclusions to exclude non\-standard clients +-such as netcat. Specify "smtpd_forbid_bare_newline = no" to disable +-(not recommended for an Internet\-connected MTA). +-.PP +-See +-https://www.postfix.org/smtp\-smuggling.html for details. ++Reject or restrict input lines from an SMTP client that end in ++<LF> instead of the standard <CR><LF>. Such line ++endings are commonly allowed with UNIX\-based SMTP servers, but they ++violate RFC 5321, and allowing such line endings can make a server ++vulnerable to ++SMTP smuggling. ++.PP ++Specify one of the following values (case does not matter): ++.IP "\fBnormalize\fR" ++Require the standard ++End\-of\-DATA sequence <CR><LF>.<CR><LF>. ++Otherwise, allow command or message content lines ending in the ++non\-standard <LF>, and process them as if the client sent the ++standard <CR><LF>. ++.br ++.br ++This maintains compatibility ++with many legitimate SMTP client applications that send a mix of ++standard and non\-standard line endings, but will fail to receive ++email from client implementations that do not terminate DATA content ++with the standard End\-of\-DATA sequence ++<CR><LF>.<CR><LF>. ++.br ++.br ++Such clients ++can be excluded with smtpd_forbid_bare_newline_exclusions. ++.br ++.IP "\fByes\fR" ++Compatibility alias for \fBnormalize\fR. ++.br ++.IP "\fBreject\fR" ++Require the standard End\-of\-DATA ++sequence <CR><LF>.<CR><LF>. Reject a command ++or message content when a line contains bare <LF>, log a "bare ++<LF> received" error, and reply with the SMTP status code in ++$smtpd_forbid_bare_newline_reject_code. ++.br ++.br ++This will reject ++email from SMTP clients that send any non\-standard line endings ++such as web applications, netcat, or load balancer health checks. ++.br ++.br ++This will also reject email from services that use BDAT ++to send MIME text containing a bare newline (RFC 3030 Section 3 ++requires canonical MIME format for text message types, defined in ++RFC 2045 Sections 2.7 and 2.8). ++.br ++.br ++Such clients can be ++excluded with smtpd_forbid_bare_newline_exclusions (or, in the case ++of BDAT violations, BDAT can be selectively disabled with ++smtpd_discard_ehlo_keyword_address_maps, or globally disabled with ++smtpd_discard_ehlo_keywords). ++.br ++.IP "\fBno\fR (default)" ++Do not require the standard ++End\-of\-DATA ++sequence <CR><LF>.<CR><LF>. Always process ++a bare <LF> as if the client sent <CR><LF>. This ++option is fully backwards compatible, but is not recommended for ++an Internet\-facing SMTP server, because it is vulnerable to SMTP smuggling. ++.br ++.br + .PP +-Example: ++Recommended settings: + .sp + .in +4 + .nf + .na + .ft C +-# Disconnect remote SMTP clients that send bare newlines, but allow +-# local clients with non\-standard SMTP implementations such as netcat, +-# fax machines, or load balancer health checks. ++# Require the standard End\-of\-DATA sequence <CR><LF>.<CR><LF>. ++# Otherwise, allow bare <LF> and process it as if the client sent ++# <CR><LF>. + # +-smtpd_forbid_bare_newline = yes ++# This maintains compatibility with many legitimate SMTP client ++# applications that send a mix of standard and non\-standard line ++# endings, but will fail to receive email from client implementations ++# that do not terminate DATA content with the standard End\-of\-DATA ++# sequence <CR><LF>.<CR><LF>. ++# ++# Such clients can be allowlisted with smtpd_forbid_bare_newline_exclusions. ++# The example below allowlists SMTP clients in trusted networks. ++# ++smtpd_forbid_bare_newline = normalize + smtpd_forbid_bare_newline_exclusions = $mynetworks + .fi + .ad + .ft R + .in -4 + .PP +-This feature is available in Postfix >= 3.9, 3.8.4, 3.7.9, +-3.6.13, and 3.5.23. +-.SH smtpd_forbid_bare_newline_exclusions (default: $mynetworks) +-Exclude the specified clients from smtpd_forbid_bare_newline +-enforcement. It uses the same syntax and parent\-domain matching +-behavior as mynetworks. +-.PP +-Example: ++Alternative: + .sp + .in +4 + .nf + .na + .ft C +-# Disconnect remote SMTP clients that send bare newlines, but allow +-# local clients with non\-standard SMTP implementations such as netcat, +-# fax machines, or load balancer health checks. ++# Reject input lines that contain <LF> and log a "bare <LF> received" ++# error. Require that input lines end in <CR><LF>, and require the ++# standard End\-of\-DATA sequence <CR><LF>.<CR><LF>. ++# ++# This will reject email from SMTP clients that send any non\-standard ++# line endings such as web applications, netcat, or load balancer ++# health checks. + # +-smtpd_forbid_bare_newline = yes ++# This will also reject email from services that use BDAT to send ++# MIME text containing a bare newline (RFC 3030 Section 3 requires ++# canonical MIME format for text message types, defined in RFC 2045 ++# Sections 2.7 and 2.8). ++# ++# Such clients can be allowlisted with smtpd_forbid_bare_newline_exclusions. ++# The example below allowlists SMTP clients in trusted networks. ++# ++smtpd_forbid_bare_newline = reject + smtpd_forbid_bare_newline_exclusions = $mynetworks ++# ++# Alternatively, in the case of BDAT violations, BDAT can be selectively ++# disabled with smtpd_discard_ehlo_keyword_address_maps, or globally ++# disabled with smtpd_discard_ehlo_keywords. ++# ++# smtpd_discard_ehlo_keyword_address_maps = cidr:/path/to/file ++# /path/to/file: ++# 10.0.0.0/24 chunking, silent\-discard ++# smtpd_discard_ehlo_keywords = chunking, silent\-discard + .fi + .ad + .ft R + .in -4 + .PP ++This feature with settings \fByes\fR and \fBno\fR is available ++in Postfix 3.8.4, 3.7.9, 3.6.13, and 3.5.23. Additionally, the ++settings \fBreject\fR, and \fBnormalize\fR are available with ++Postfix >= 3.9, 3.8.5, 3.7.10, 3.6.14, and 3.5.24. ++.SH smtpd_forbid_bare_newline_exclusions (default: $mynetworks) ++Exclude the specified clients from smtpd_forbid_bare_newline ++enforcement. This setting uses the same syntax and parent\-domain ++matching behavior as mynetworks. ++.PP + This feature is available in Postfix >= 3.9, 3.8.4, 3.7.9, + 3.6.13, and 3.5.23. ++.SH smtpd_forbid_bare_newline_reject_code (default: 550) ++The numerical Postfix SMTP server response code when rejecting a ++request with "smtpd_forbid_bare_newline = reject". ++Specify a 5XX status code (521 to disconnect). ++.PP ++This feature is available in Postfix >= 3.9, 3.8.5, 3.7.10, ++3.6.14, and 3.5.24. + .SH smtpd_forbidden_commands (default: CONNECT, GET, POST) + List of commands that cause the Postfix SMTP server to immediately + terminate the session with a 221 code. This can be used to disconnect +--- a/man/man8/cleanup.8 ++++ b/man/man8/cleanup.8 +@@ -163,6 +163,14 @@ + .IP "\fBmessage_strip_characters (empty)\fR" + The set of characters that Postfix will remove from message + content. ++.PP ++Available in Postfix version 3.9, 3.8.5, 3.7.10, 3.6.14, ++3.5.24, and later: ++.IP "\fBcleanup_replace_stray_cr_lf (yes)\fR" ++Replace each stray <CR> or <LF> character in message ++content with a space character, to prevent outbound SMTP smuggling, ++and to make the evaluation of Postfix\-added DKIM or other signatures ++independent from how a remote mail server handles such characters. + .SH "BEFORE QUEUE MILTER CONTROLS" + .na + .nf +--- a/man/man8/smtpd.8 ++++ b/man/man8/smtpd.8 +@@ -811,12 +811,17 @@ + .PP + Available in Postfix 3.9, 3.8.4, 3.7.9, 3.6.13, 3.5.23 and later: + .IP "\fBsmtpd_forbid_bare_newline (Postfix < 3.9: no)\fR" +-Reply with "Error: bare <LF> received" and disconnect +-when a remote SMTP client sends a line ending in <LF>, violating +-the RFC 5321 requirement that lines must end in <CR><LF>. ++Reject or restrict input lines from an SMTP client that end in ++<LF> instead of the standard <CR><LF>. + .IP "\fBsmtpd_forbid_bare_newline_exclusions ($mynetworks)\fR" + Exclude the specified clients from smtpd_forbid_bare_newline + enforcement. ++.PP ++Available in Postfix 3.9, 3.8.5, 3.7.10, 3.6.14, 3.5.24 and ++later: ++.IP "\fBsmtpd_forbid_bare_newline_reject_code (550)\fR" ++The numerical Postfix SMTP server response code when rejecting a ++request with "smtpd_forbid_bare_newline = reject". + .SH "TARPIT CONTROLS" + .na + .nf +--- a/mantools/postlink ++++ b/mantools/postlink +@@ -547,8 +547,10 @@ + s;\bsmtpd_error_sleep_time\b;<a href="postconf.5.html#smtpd_error_sleep_time">$&</a>;g; + s;\bsmtpd_etrn_restrictions\b;<a href="postconf.5.html#smtpd_etrn_restrictions">$&</a>;g; + s;\bsmtpd_expansion_filter\b;<a href="postconf.5.html#smtpd_expansion_filter">$&</a>;g; +- s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_bare_newline\b;<a href="postconf.5.html#smtpd_forbi d_bare_newline">$&</a>;g; +- s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_bare_newline_exclusions\b;<a href="postconf.5.html# smtpd_forbid_bare_newline_exclusions">$&</a>;g; ++ s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_bare_new[-</bB>]*\n*[ <bB>]*line\b;<a href="postconf.5.html#smtpd_forbid_bare_newline">$&</a>;g; ++ s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_bare_new[-</bB>]*\n*[ <bB>]*line_reject_code\b;<a href="postconf.5.html#smtpd_forbid_bare_newline_reject_code">$&</a>;g; ++ s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bid_bare_new[-</bB>]*\n*[ <bB>]*line_exclusions\b;<a href="postconf.5.html#smtpd_forbid_bare_newline_exclusions">$&</a>;g; ++ s;\bcleanup_replace_stray_cr_lf\b;<a href="postconf.5.html#cleanup_replace_stray_cr_lf">$&</a>;g; + s;\bsmtpd_for[-</bB>]*\n*[ <bB>]*bidden_commands\b;<a href="postconf.5.html#smtpd_forbidden_commands">$&</a>;g; + s;\bsmtpd_hard_error_limit\b;<a href="postconf.5.html#smtpd_hard_error_limit">$&</a>;g; + s;\bsmtpd_helo_required\b;<a href="postconf.5.html#smtpd_helo_required">$&</a>;g; +--- a/proto/postconf.proto ++++ b/proto/postconf.proto +@@ -18061,52 +18061,138 @@ + + %PARAM smtpd_forbid_bare_newline Postfix < 3.9: no + +-<p> Reply with "Error: bare <LF> received" and disconnect +-when a remote SMTP client sends a line ending in <LF>, violating +-the RFC 5321 requirement that lines must end in <CR><LF>. +-This feature is disbled by default with Postfix < 3.9. Use +-smtpd_forbid_bare_newline_exclusions to exclude non-standard clients +-such as netcat. Specify "smtpd_forbid_bare_newline = no" to disable +-(not recommended for an Internet-connected MTA). </p> ++<p> Reject or restrict input lines from an SMTP client that end in ++<LF> instead of the standard <CR><LF>. Such line ++endings are commonly allowed with UNIX-based SMTP servers, but they ++violate RFC 5321, and allowing such line endings can make a server ++vulnerable to <a href="https://www.postfix.org/smtp-smuggling.html"> ++SMTP smuggling</a>. </p> ++ ++<p> Specify one of the following values (case does not matter): </p> ++ ++<dl compact> ++ ++<dt> <b>normalize</b></dt> <dd> Require the standard ++End-of-DATA sequence <CR><LF>.<CR><LF>. ++Otherwise, allow command or message content lines ending in the ++non-standard <LF>, and process them as if the client sent the ++standard <CR><LF>. <br> <br> This maintains compatibility ++with many legitimate SMTP client applications that send a mix of ++standard and non-standard line endings, but will fail to receive ++email from client implementations that do not terminate DATA content ++with the standard End-of-DATA sequence ++<CR><LF>.<CR><LF>. <br> <br> Such clients ++can be excluded with smtpd_forbid_bare_newline_exclusions. </dd> ++ ++<dt> <b>yes</b> </dt> <dd> Compatibility alias for <b>normalize</b>. </dd> ++ ++<dt> <b>reject</b> </dt> <dd> Require the standard End-of-DATA ++sequence <CR><LF>.<CR><LF>. Reject a command ++or message content when a line contains bare <LF>, log a "bare ++<LF> received" error, and reply with the SMTP status code in ++$smtpd_forbid_bare_newline_reject_code. <br> <br> This will reject ++email from SMTP clients that send any non-standard line endings ++such as web applications, netcat, or load balancer health checks. ++<br> <br> This will also reject email from services that use BDAT ++to send MIME text containing a bare newline (RFC 3030 Section 3 ++requires canonical MIME format for text message types, defined in ++RFC 2045 Sections 2.7 and 2.8). <br> <br> Such clients can be ++excluded with smtpd_forbid_bare_newline_exclusions (or, in the case ++of BDAT violations, BDAT can be selectively disabled with ++smtpd_discard_ehlo_keyword_address_maps, or globally disabled with ++smtpd_discard_ehlo_keywords). </dd> ++ ++<dt> <b>no</b> (default)</dt> <dd> Do not require the standard ++End-of-DATA ++sequence <CR><LF>.<CR><LF>. Always process ++a bare <LF> as if the client sent <CR><LF>. This ++option is fully backwards compatible, but is not recommended for ++an Internet-facing SMTP server, because it is vulnerable to <a ++href="https://www.postfix.org/smtp-smuggling.html"> SMTP smuggling</a>. ++</dd> + +-<p> See <a href="https://www.postfix.org/smtp-smuggling.html"> +-https://www.postfix.org/smtp-smuggling.html</a> for details. ++</dl> + +-<p> Example: </p> ++<p> Recommended settings: </p> + + <blockquote> + <pre> +-# Disconnect remote SMTP clients that send bare newlines, but allow +-# local clients with non-standard SMTP implementations such as netcat, +-# fax machines, or load balancer health checks. ++# Require the standard End-of-DATA sequence <CR><LF>.<CR><LF>. ++# Otherwise, allow bare <LF> and process it as if the client sent ++# <CR><LF>. + # +-smtpd_forbid_bare_newline = yes ++# This maintains compatibility with many legitimate SMTP client ++# applications that send a mix of standard and non-standard line ++# endings, but will fail to receive email from client implementations ++# that do not terminate DATA content with the standard End-of-DATA ++# sequence <CR><LF>.<CR><LF>. ++# ++# Such clients can be allowlisted with smtpd_forbid_bare_newline_exclusions. ++# The example below allowlists SMTP clients in trusted networks. ++# ++smtpd_forbid_bare_newline = normalize + smtpd_forbid_bare_newline_exclusions = $mynetworks + </pre> + </blockquote> + +-<p> This feature is available in Postfix ≥ 3.9, 3.8.4, 3.7.9, +-3.6.13, and 3.5.23. </p> +- +-%PARAM smtpd_forbid_bare_newline_exclusions $mynetworks +- +-<p> Exclude the specified clients from smtpd_forbid_bare_newline +-enforcement. It uses the same syntax and parent-domain matching +-behavior as mynetworks. </p> +- +-<p> Example: </p> ++<p> Alternative: </p> + + <blockquote> + <pre> +-# Disconnect remote SMTP clients that send bare newlines, but allow +-# local clients with non-standard SMTP implementations such as netcat, +-# fax machines, or load balancer health checks. ++# Reject input lines that contain <LF> and log a "bare <LF> received" ++# error. Require that input lines end in <CR><LF>, and require the ++# standard End-of-DATA sequence <CR><LF>.<CR><LF>. ++# ++# This will reject email from SMTP clients that send any non-standard ++# line endings such as web applications, netcat, or load balancer ++# health checks. ++# ++# This will also reject email from services that use BDAT to send ++# MIME text containing a bare newline (RFC 3030 Section 3 requires ++# canonical MIME format for text message types, defined in RFC 2045 ++# Sections 2.7 and 2.8). ++# ++# Such clients can be allowlisted with smtpd_forbid_bare_newline_exclusions. ++# The example below allowlists SMTP clients in trusted networks. + # +-smtpd_forbid_bare_newline = yes ++smtpd_forbid_bare_newline = reject + smtpd_forbid_bare_newline_exclusions = $mynetworks ++# ++# Alternatively, in the case of BDAT violations, BDAT can be selectively ++# disabled with smtpd_discard_ehlo_keyword_address_maps, or globally ++# disabled with smtpd_discard_ehlo_keywords. ++# ++# smtpd_discard_ehlo_keyword_address_maps = cidr:/path/to/file ++# /path/to/file: ++# 10.0.0.0/24 chunking, silent-discard ++# smtpd_discard_ehlo_keywords = chunking, silent-discard + </pre> + </blockquote> + ++<p> This feature with settings <b>yes</b> and <b>no</b> is available ++in Postfix 3.8.4, 3.7.9, 3.6.13, and 3.5.23. Additionally, the ++settings <b>reject</b>, and <b>normalize</b> are available with ++Postfix ≥ 3.9, 3.8.5, 3.7.10, 3.6.14, and 3.5.24. </p> ++ ++%PARAM smtpd_forbid_bare_newline_exclusions $mynetworks ++ ++<p> Exclude the specified clients from smtpd_forbid_bare_newline ++enforcement. This setting uses the same syntax and parent-domain ++matching behavior as mynetworks. </p> ++ + <p> This feature is available in Postfix ≥ 3.9, 3.8.4, 3.7.9, + 3.6.13, and 3.5.23. </p> + ++%PARAM smtpd_forbid_bare_newline_reject_code 550 ++ ++<p> ++The numerical Postfix SMTP server response code when rejecting a ++request with "smtpd_forbid_bare_newline = reject". ++Specify a 5XX status code (521 to disconnect). ++</p> ++ ++<p> This feature is available in Postfix ≥ 3.9, 3.8.5, 3.7.10, ++3.6.14, and 3.5.24. </p> ++ ++%PARAM cleanup_replace_stray_cr_lf yes ++ +--- a/src/cleanup/cleanup.c ++++ b/src/cleanup/cleanup.c +@@ -145,6 +145,14 @@ + /* .IP "\fBmessage_strip_characters (empty)\fR" + /* The set of characters that Postfix will remove from message + /* content. ++/* .PP ++/* Available in Postfix version 3.9, 3.8.5, 3.7.10, 3.6.14, ++/* 3.5.24, and later: ++/* .IP "\fBcleanup_replace_stray_cr_lf (yes)\fR" ++/* Replace each stray <CR> or <LF> character in message ++/* content with a space character, to prevent outbound SMTP smuggling, ++/* and to make the evaluation of Postfix-added DKIM or other signatures ++/* independent from how a remote mail server handles such characters. + /* BEFORE QUEUE MILTER CONTROLS + /* .ad + /* .fi +--- a/src/cleanup/cleanup_init.c ++++ b/src/cleanup/cleanup_init.c +@@ -173,6 +173,7 @@ + int var_always_add_hdrs; /* always add missing headers */ + int var_virt_addrlen_limit; /* stop exponential growth */ + char *var_hfrom_format; /* header_from_format */ ++int var_cleanup_mask_stray_cr_lf; /* replace stray CR or LF with space */ + + const CONFIG_INT_TABLE cleanup_int_table[] = { + VAR_HOPCOUNT_LIMIT, DEF_HOPCOUNT_LIMIT, &var_hopcount_limit, 1, 0, +@@ -189,6 +190,7 @@ + VAR_VERP_BOUNCE_OFF, DEF_VERP_BOUNCE_OFF, &var_verp_bounce_off, + VAR_AUTO_8BIT_ENC_HDR, DEF_AUTO_8BIT_ENC_HDR, &var_auto_8bit_enc_hdr, + VAR_ALWAYS_ADD_HDRS, DEF_ALWAYS_ADD_HDRS, &var_always_add_hdrs, ++ VAR_CLEANUP_MASK_STRAY_CR_LF, DEF_CLEANUP_MASK_STRAY_CR_LF, &var_cleanup_mask_stray_cr_lf, + 0, + }; + +--- a/src/cleanup/cleanup_message.c ++++ b/src/cleanup/cleanup_message.c +@@ -930,6 +930,23 @@ + char *dst; + + /* ++ * Replace each stray CR or LF with one space. These are not allowed in ++ * SMTP, and can be used to enable outbound (remote) SMTP smuggling. ++ * Replacing these early ensures that our later DKIM etc. signature will ++ * not be invalidated. Besides preventing SMTP smuggling, replacing stray ++ * <CR> or <LF> ensures that the result of signature validation by a ++ * later mail system will not depend on how that mail system handles ++ * those stray characters in an implementation-dependent manner. ++ * ++ * The input length is not changed, therefore it is safe to overwrite the ++ * input. ++ */ ++ if (var_cleanup_mask_stray_cr_lf) ++ for (dst = (char *) buf; dst < buf + len; dst++) ++ if (*dst == '\r' || *dst == '\n') ++ *dst = ' '; ++ ++ /* + * Reject unwanted characters. + * + * XXX Possible optimization: simplify the loop when the "reject" set +--- a/src/global/cleanup_strerror.c ++++ b/src/global/cleanup_strerror.c +@@ -73,6 +73,7 @@ + CLEANUP_STAT_CONT, 550, "5.7.1", "message content rejected", + CLEANUP_STAT_WRITE, 451, "4.3.0", "queue file write error", + CLEANUP_STAT_NOPERM, 550, "5.7.1", "service denied", ++ CLEANUP_STAT_BARE_LF, 521, "5.5.2", "bare <LF> received", + }; + + static CLEANUP_STAT_DETAIL cleanup_stat_success = { +--- a/src/global/cleanup_user.h ++++ b/src/global/cleanup_user.h +@@ -65,6 +65,12 @@ + #define CLEANUP_STAT_NOPERM (1<<9) /* Denied by non-content policy */ + + /* ++ * Non-cleanup errors that live in the same bitmask space, to centralize ++ * error handling. ++ */ ++#define CLEANUP_STAT_BARE_LF (1<<16) /* Bare <LF> received */ ++ ++ /* + * These are set when we can't bounce even if we were asked to. + */ + #define CLEANUP_STAT_MASK_CANT_BOUNCE \ +--- a/src/global/mail_params.h ++++ b/src/global/mail_params.h +@@ -4173,11 +4173,18 @@ + * Backwards compatibility. + */ + #define VAR_SMTPD_FORBID_BARE_LF "smtpd_forbid_bare_newline" +-#define DEF_SMTPD_FORBID_BARE_LF 0 ++#define DEF_SMTPD_FORBID_BARE_LF "no" + + #define VAR_SMTPD_FORBID_BARE_LF_EXCL "smtpd_forbid_bare_newline_exclusions" + #define DEF_SMTPD_FORBID_BARE_LF_EXCL "$" VAR_MYNETWORKS + ++#define VAR_SMTPD_FORBID_BARE_LF_CODE "smtpd_forbid_bare_newline_reject_code" ++#define DEF_SMTPD_FORBID_BARE_LF_CODE 550 ++ ++#define VAR_CLEANUP_MASK_STRAY_CR_LF "cleanup_replace_stray_cr_lf" ++#define DEF_CLEANUP_MASK_STRAY_CR_LF 1 ++extern int var_cleanup_mask_stray_cr_lf; ++ + /* + * Share TLS sessions through tlsproxy(8). + */ +--- a/src/global/smtp_stream.c ++++ b/src/global/smtp_stream.c +@@ -51,7 +51,8 @@ + /* char *format; + /* va_list ap; + /* +-/* int smtp_forbid_bare_lf; ++/* int smtp_detect_bare_lf; ++/* int smtp_got_bare_lf; + /* AUXILIARY API + /* int smtp_get_noexcept(vp, stream, maxlen, flags) + /* VSTRING *vp; +@@ -126,16 +127,16 @@ + /* smtp_vprintf() is the machine underneath smtp_printf(). + /* + /* smtp_get_noexcept() implements the subset of smtp_get() +-/* without long jumps for timeout or EOF errors. Instead, ++/* without timeouts and without making long jumps. Instead, + /* query the stream status with vstream_feof() etc. +-/* This function will make a VSTREAM long jump (error code +-/* SMTP_ERR_LF) when rejecting input with a bare newline byte. ++/* ++/* This function assigns smtp_got_bare_lf = smtp_detect_bare_lf, ++/* if smtp_detect_bare_lf is non-zero and the last read line ++/* was terminated with a bare newline. Otherwise, this function ++/* sets smtp_got_bare_lf to zero. + /* + /* smtp_timeout_setup() is a backwards-compatibility interface + /* for programs that don't require per-record deadline support. +-/* +-/* smtp_forbid_bare_lf controls whether smtp_get_noexcept() +-/* will reject input with a bare newline byte. + /* DIAGNOSTICS + /* .fi + /* .ad +@@ -208,7 +209,8 @@ + + #include "smtp_stream.h" + +-int smtp_forbid_bare_lf; ++int smtp_detect_bare_lf; ++int smtp_got_bare_lf; + + /* smtp_timeout_reset - reset per-stream error flags, restart deadline timer */ + +@@ -371,6 +373,8 @@ + int last_char; + int next_char; + ++ smtp_got_bare_lf = 0; ++ + /* + * It's painful to do I/O with records that may span multiple buffers. + * Allow for partial long lines (we will read the remainder later) and +@@ -413,11 +417,15 @@ + */ + case '\n': + vstring_truncate(vp, VSTRING_LEN(vp) - 1); +- if (smtp_forbid_bare_lf +- && (VSTRING_LEN(vp) == 0 || vstring_end(vp)[-1] != '\r')) +- vstream_longjmp(stream, SMTP_ERR_LF); +- while (VSTRING_LEN(vp) > 0 && vstring_end(vp)[-1] == '\r') +- vstring_truncate(vp, VSTRING_LEN(vp) - 1); ++ if (smtp_detect_bare_lf) { ++ if (VSTRING_LEN(vp) == 0 || vstring_end(vp)[-1] != '\r') ++ smtp_got_bare_lf = smtp_detect_bare_lf; ++ else ++ vstring_truncate(vp, VSTRING_LEN(vp) - 1); ++ } else { ++ while (VSTRING_LEN(vp) > 0 && vstring_end(vp)[-1] == '\r') ++ vstring_truncate(vp, VSTRING_LEN(vp) - 1); ++ } + VSTRING_TERMINATE(vp); + /* FALLTRHOUGH */ + +--- a/src/global/smtp_stream.h ++++ b/src/global/smtp_stream.h +@@ -32,7 +32,6 @@ + #define SMTP_ERR_QUIET 3 /* silent cleanup (application) */ + #define SMTP_ERR_NONE 4 /* non-error case */ + #define SMTP_ERR_DATA 5 /* application data error */ +-#define SMTP_ERR_LF 6 /* bare <LF> protocol error */ + + extern void smtp_stream_setup(VSTREAM *, int, int); + extern void PRINTFLIKE(2, 3) smtp_printf(VSTREAM *, const char *,...); +@@ -44,7 +43,8 @@ + extern void smtp_fwrite(const char *, ssize_t len, VSTREAM *); + extern void smtp_fread_buf(VSTRING *, ssize_t len, VSTREAM *); + extern void smtp_fputc(int, VSTREAM *); +-extern int smtp_forbid_bare_lf; ++extern int smtp_detect_bare_lf; ++extern int smtp_got_bare_lf; + + extern void smtp_vprintf(VSTREAM *, const char *, va_list); + +--- a/src/smtpd/smtpd.c ++++ b/src/smtpd/smtpd.c +@@ -765,12 +765,17 @@ + /* .PP + /* Available in Postfix 3.9, 3.8.4, 3.7.9, 3.6.13, 3.5.23 and later: + /* .IP "\fBsmtpd_forbid_bare_newline (Postfix < 3.9: no)\fR" +-/* Reply with "Error: bare <LF> received" and disconnect +-/* when a remote SMTP client sends a line ending in <LF>, violating +-/* the RFC 5321 requirement that lines must end in <CR><LF>. ++/* Reject or restrict input lines from an SMTP client that end in ++/* <LF> instead of the standard <CR><LF>. + /* .IP "\fBsmtpd_forbid_bare_newline_exclusions ($mynetworks)\fR" + /* Exclude the specified clients from smtpd_forbid_bare_newline + /* enforcement. ++/* .PP ++/* Available in Postfix 3.9, 3.8.5, 3.7.10, 3.6.14, 3.5.24 and ++/* later: ++/* .IP "\fBsmtpd_forbid_bare_newline_reject_code (550)\fR" ++/* The numerical Postfix SMTP server response code when rejecting a ++/* request with "smtpd_forbid_bare_newline = reject". + /* TARPIT CONTROLS + /* .ad + /* .fi +@@ -1476,8 +1481,10 @@ + int var_smtpd_uproxy_tmout; + bool var_relay_before_rcpt_checks; + +-bool var_smtpd_forbid_bare_lf; ++char *var_smtpd_forbid_bare_lf; + char *var_smtpd_forbid_bare_lf_excl; ++int var_smtpd_forbid_bare_lf_code; ++static int bare_lf_mask; + static NAMADR_LIST *bare_lf_excl; + + /* +@@ -1554,7 +1561,6 @@ + #define REASON_TIMEOUT "timeout" + #define REASON_LOST_CONNECTION "lost connection" + #define REASON_ERROR_LIMIT "too many errors" +-#define REASON_BARE_LF "bare <LF> received" + + #ifdef USE_TLS + +@@ -1573,6 +1579,40 @@ + */ + static DICT *smtpd_cmd_filter; + ++ /* ++ * Bare LF and End-of-DATA controls (bare CR is handled elsewhere). ++ * ++ * At the smtp_get*() line reader level, setting any of these flags in the ++ * smtp_detect_bare_lf variable enables the detection of bare newlines. The ++ * line reader will set the same flags in the smtp_got_bare_lf variable ++ * after it detects a bare newline, otherwise it clears smtp_got_bare_lf. ++ * ++ * At the SMTP command level, the flags in smtp_got_bare_lf control whether ++ * commands ending in a bare newline are rejected. ++ * ++ * At the DATA and BDAT content level, the flags in smtp_got_bare_lf control ++ * whether the standard End-of-DATA sequence CRLF.CRLF is required, and ++ * whether lines ending in bare newlines are rejected. ++ * ++ * Postfix implements "delayed reject" after detecting a bare newline in BDAT ++ * or DATA content. The SMTP server delays a REJECT response until the ++ * command is finished, instead of replying and hanging up immediately. The ++ * End-of-DATA detection is secured with BARE_LF_FLAG_WANT_STD_EOD. ++ */ ++#define BARE_LF_FLAG_WANT_STD_EOD (1<<0) /* Require CRLF.CRLF */ ++#define BARE_LF_FLAG_REPLY_REJECT (1<<1) /* Reject bare newline */ ++ ++#define IS_BARE_LF_WANT_STD_EOD(m) ((m) & BARE_LF_FLAG_WANT_STD_EOD) ++#define IS_BARE_LF_REPLY_REJECT(m) ((m) & BARE_LF_FLAG_REPLY_REJECT) ++ ++static const NAME_CODE bare_lf_mask_table[] = { ++ "normalize", BARE_LF_FLAG_WANT_STD_EOD, /* Default */ ++ "yes", BARE_LF_FLAG_WANT_STD_EOD, /* Migration aid */ ++ "reject", BARE_LF_FLAG_WANT_STD_EOD | BARE_LF_FLAG_REPLY_REJECT, ++ "no", 0, ++ 0, -1, /* error */ ++}; ++ + #ifdef USE_SASL_AUTH + + /* +@@ -3515,6 +3555,7 @@ + int curr_rec_type; + int prev_rec_type; + int first = 1; ++ int prev_got_bare_lf = 0; + + /* + * Copy the message content. If the cleanup process has a problem, keep +@@ -3528,12 +3569,15 @@ + * XXX Deal with UNIX-style From_ lines at the start of message content + * because sendmail permits it. + */ +- for (prev_rec_type = 0; /* void */ ; prev_rec_type = curr_rec_type) { ++ for (prev_rec_type = 0; /* void */ ; prev_rec_type = curr_rec_type, ++ prev_got_bare_lf = smtp_got_bare_lf) { + if (smtp_get(state->buffer, state->client, var_line_limit, + SMTP_GET_FLAG_NONE) == '\n') + curr_rec_type = REC_TYPE_NORM; + else + curr_rec_type = REC_TYPE_CONT; ++ if (IS_BARE_LF_REPLY_REJECT(smtp_got_bare_lf)) ++ state->err |= CLEANUP_STAT_BARE_LF; + start = vstring_str(state->buffer); + len = VSTRING_LEN(state->buffer); + if (first) { +@@ -3546,9 +3590,14 @@ + if (len > 0 && IS_SPACE_TAB(start[0])) + out_record(out_stream, REC_TYPE_NORM, "", 0); + } +- if (prev_rec_type != REC_TYPE_CONT && *start == '.' +- && (proxy == 0 ? (++start, --len) == 0 : len == 1)) +- break; ++ if (prev_rec_type != REC_TYPE_CONT && *start == '.') { ++ if (len == 1 && IS_BARE_LF_WANT_STD_EOD(smtp_detect_bare_lf) ++ && (smtp_got_bare_lf || prev_got_bare_lf)) ++ /* Do not store or send to proxy filter. */ ++ continue; ++ if (proxy == 0 ? (++start, --len) == 0 : len == 1) ++ break; ++ } + if (state->err == CLEANUP_STAT_OK) { + if (ENFORCING_SIZE_LIMIT(var_message_limit) + && var_message_limit - state->act_size < len + 2) { +@@ -3701,6 +3750,11 @@ + else + smtpd_chat_reply(state, + "250 2.0.0 Ok: queued as %s", state->queue_id); ++ } else if ((state->err & CLEANUP_STAT_BARE_LF) != 0) { ++ state->error_mask |= MAIL_ERROR_PROTOCOL; ++ log_whatsup(state, "reject", "bare <LF> received"); ++ smtpd_chat_reply(state, "%d 5.5.2 %s Error: bare <LF> received", ++ var_smtpd_forbid_bare_lf_code, var_myhostname); + } else if (why && IS_SMTP_REJECT(STR(why))) { + state->error_mask |= MAIL_ERROR_POLICY; + smtpd_chat_reply(state, "%s", STR(why)); +@@ -3981,7 +4035,6 @@ + */ + done = 0; + do { +- int payload_err; + + /* + * Do not skip the smtp_fread_buf() call if read_len == 0. We still +@@ -3995,10 +4048,6 @@ + smtp_fread_buf(state->buffer, read_len, state->client); + state->bdat_get_stream = vstream_memreopen( + state->bdat_get_stream, state->buffer, O_RDONLY); +- vstream_control(state->bdat_get_stream, CA_VSTREAM_CTL_EXCEPT, +- CA_VSTREAM_CTL_END); +- if ((payload_err = vstream_setjmp(state->bdat_get_stream)) != 0) +- vstream_longjmp(state->client, payload_err); + + /* + * Read lines from the fragment. The last line may continue in the +@@ -4023,6 +4072,8 @@ + /* Skip the out_record() and VSTRING_RESET() calls below. */ + break; + } ++ if (IS_BARE_LF_REPLY_REJECT(smtp_got_bare_lf)) ++ state->err |= CLEANUP_STAT_BARE_LF; + start = vstring_str(state->bdat_get_buffer); + len = VSTRING_LEN(state->bdat_get_buffer); + if (state->err == CLEANUP_STAT_OK) { +@@ -4674,9 +4725,9 @@ + */ + xclient_allowed = + namadr_list_match(xclient_hosts, state->name, state->addr); +- smtp_forbid_bare_lf = SMTPD_STAND_ALONE((state)) == 0 +- && var_smtpd_forbid_bare_lf +- && !namadr_list_match(bare_lf_excl, state->name, state->addr); ++ smtp_detect_bare_lf = (SMTPD_STAND_ALONE((state)) == 0 && bare_lf_mask ++ && !namadr_list_match(bare_lf_excl, state->name, state->addr)) ? ++ bare_lf_mask : 0; + /* NOT: tls_reset() */ + if (got_helo == 0) + helo_reset(state); +@@ -5468,13 +5519,6 @@ + var_myhostname); + break; + +- case SMTP_ERR_LF: +- state->reason = REASON_BARE_LF; +- if (vstream_setjmp(state->client) == 0) +- smtpd_chat_reply(state, "521 5.5.2 %s Error: bare <LF> received", +- var_myhostname); +- break; +- + case 0: + + /* +@@ -5676,6 +5720,13 @@ + } + watchdog_pat(); + smtpd_chat_query(state); ++ if (IS_BARE_LF_REPLY_REJECT(smtp_got_bare_lf)) { ++ log_whatsup(state, "reject", "bare <LF> received"); ++ state->error_mask |= MAIL_ERROR_PROTOCOL; ++ smtpd_chat_reply(state, "%d 5.5.2 %s Error: bare <LF> received", ++ var_smtpd_forbid_bare_lf_code, var_myhostname); ++ break; ++ } + /* Safety: protect internal interfaces against malformed UTF-8. */ + if (var_smtputf8_enable && valid_utf8_string(STR(state->buffer), + LEN(state->buffer)) == 0) { +@@ -6024,11 +6075,11 @@ + namadr_list_match(xforward_hosts, state.name, state.addr); + + /* +- * Enforce strict SMTP line endings, with compatibility exclusions. ++ * Reject or normalize bare LF, with compatibility exclusions. + */ +- smtp_forbid_bare_lf = SMTPD_STAND_ALONE((&state)) == 0 +- && var_smtpd_forbid_bare_lf +- && !namadr_list_match(bare_lf_excl, state.name, state.addr); ++ smtp_detect_bare_lf = (SMTPD_STAND_ALONE((&state)) == 0 && bare_lf_mask ++ && !namadr_list_match(bare_lf_excl, state.name, state.addr)) ? ++ bare_lf_mask : 0; + + /* + * See if we need to turn on verbose logging for this client. +@@ -6095,6 +6146,10 @@ + MATCH_FLAG_RETURN + | match_parent_style(VAR_MYNETWORKS), + var_smtpd_forbid_bare_lf_excl); ++ if ((bare_lf_mask = name_code(bare_lf_mask_table, NAME_CODE_FLAG_NONE, ++ var_smtpd_forbid_bare_lf)) < 0) ++ msg_fatal("bad parameter value: '%s = %s'", ++ VAR_SMTPD_FORBID_BARE_LF, var_smtpd_forbid_bare_lf); + + /* + * Open maps before dropping privileges so we can read passwords etc. +@@ -6390,6 +6445,7 @@ + VAR_VIRT_MAILBOX_CODE, DEF_VIRT_MAILBOX_CODE, &var_virt_mailbox_code, 0, 0, + VAR_RELAY_RCPT_CODE, DEF_RELAY_RCPT_CODE, &var_relay_rcpt_code, 0, 0, + VAR_PLAINTEXT_CODE, DEF_PLAINTEXT_CODE, &var_plaintext_code, 0, 0, ++ VAR_SMTPD_FORBID_BARE_LF_CODE, DEF_SMTPD_FORBID_BARE_LF_CODE, &var_smtpd_forbid_bare_lf_code, 500, 599, + VAR_SMTPD_CRATE_LIMIT, DEF_SMTPD_CRATE_LIMIT, &var_smtpd_crate_limit, 0, 0, + VAR_SMTPD_CCONN_LIMIT, DEF_SMTPD_CCONN_LIMIT, &var_smtpd_cconn_limit, 0, 0, + VAR_SMTPD_CMAIL_LIMIT, DEF_SMTPD_CMAIL_LIMIT, &var_smtpd_cmail_limit, 0, 0, +@@ -6452,7 +6508,6 @@ + VAR_SMTPD_PEERNAME_LOOKUP, DEF_SMTPD_PEERNAME_LOOKUP, &var_smtpd_peername_lookup, + VAR_SMTPD_DELAY_OPEN, DEF_SMTPD_DELAY_OPEN, &var_smtpd_delay_open, + VAR_SMTPD_CLIENT_PORT_LOG, DEF_SMTPD_CLIENT_PORT_LOG, &var_smtpd_client_port_log, +- VAR_SMTPD_FORBID_BARE_LF, DEF_SMTPD_FORBID_BARE_LF, &var_smtpd_forbid_bare_lf, + 0, + }; + static const CONFIG_NBOOL_TABLE nbool_table[] = { +@@ -6569,6 +6624,7 @@ + VAR_SMTPD_DNS_RE_FILTER, DEF_SMTPD_DNS_RE_FILTER, &var_smtpd_dns_re_filter, 0, 0, + VAR_SMTPD_REJ_FTR_MAPS, DEF_SMTPD_REJ_FTR_MAPS, &var_smtpd_rej_ftr_maps, 0, 0, + VAR_SMTPD_FORBID_BARE_LF_EXCL, DEF_SMTPD_FORBID_BARE_LF_EXCL, &var_smtpd_forbid_bare_lf_excl, 0, 0, ++ VAR_SMTPD_FORBID_BARE_LF, DEF_SMTPD_FORBID_BARE_LF, &var_smtpd_forbid_bare_lf, 1, 0, + 0, + }; + static const CONFIG_RAW_TABLE raw_table[] = { +--- a/src/smtpd/smtpd_check.c ++++ b/src/smtpd/smtpd_check.c +@@ -48,6 +48,11 @@ + /* + /* char *smtpd_check_queue(state) + /* SMTPD_STATE *state; ++/* AUXILIARY FUNCTIONS ++/* void log_whatsup(state, action, text) ++/* SMTPD_STATE *state; ++/* const char *action; ++/* const char *text; + /* DESCRIPTION + /* This module implements additional checks on SMTP client requests. + /* A client request is validated in the context of the session state. +@@ -146,6 +151,11 @@ + /* The recipient address given with the RCPT TO or VRFY command. + /* .IP size + /* The message size given with the MAIL FROM command (zero if unknown). ++/* .PP ++/* log_whatsup() logs "<queueid>: <action>: <protocol state> ++/* from: <client-name[client-addr]>: <text>" plus the protocol ++/* (SMTP or ESMTP), and if available, EHLO, MAIL FROM, or RCPT ++/* TO. + /* BUGS + /* Policies like these should not be hard-coded in C, but should + /* be user-programmable instead. +@@ -987,8 +997,8 @@ + + /* log_whatsup - log as much context as we have */ + +-static void log_whatsup(SMTPD_STATE *state, const char *whatsup, +- const char *text) ++void log_whatsup(SMTPD_STATE *state, const char *whatsup, ++ const char *text) + { + VSTRING *buf = vstring_alloc(100); + +--- a/src/smtpd/smtpd_check.h ++++ b/src/smtpd/smtpd_check.h +@@ -25,6 +25,7 @@ + extern char *smtpd_check_data(SMTPD_STATE *); + extern char *smtpd_check_eod(SMTPD_STATE *); + extern char *smtpd_check_policy(SMTPD_STATE *, char *); ++extern void log_whatsup(SMTPD_STATE *, const char *, const char *); + + /* LICENSE + /* .ad |