In markdown, autolinks are dangerous. Different compilers disagree

with respect to what constitutes a valid autolink, and if a compiler
deems an autolink invalid, the input turns into an unintended and
potentially harmful raw HTML tag.  So, never write autolinks.
Instead of <link>, write [link](link).
Instead of <addr>, write [addr](mailto:addr).

Issue pointed out by bentley@, who also agrees with the general
direction of the change.

diff --git a/mdoc_markdown.c b/mdoc_markdown.c
index 1bf1c13cd3d0dfe4b2a50342329e8c2d87a1cbf9..6f80d70c417acb23e52250772145cb5b98a9f25d 100644 (file)
--- a/mdoc_markdown.c
+++ b/mdoc_markdown.c
@@ -1,4 +1,4 @@
-/*     $Id: mdoc_markdown.c,v 1.14 2017/03/08 19:23:43 schwarze Exp $ */
+/*     $Id: mdoc_markdown.c,v 1.15 2017/03/11 12:35:45 schwarze Exp $ */
 /*
  * Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
  *
@@ -43,6 +43,7 @@ static        void     md_rawword(const char *);
 static void     md_word(const char *);
 static void     md_named(const char *);
 static void     md_char(unsigned char);
+static void     md_uri(const char *);
 
 static int      md_cond_head(struct roff_node *);
 static int      md_cond_body(struct roff_node *);
@@ -67,6 +68,7 @@ static        int      md_pre_Fo(struct roff_node *);
 static int      md_pre_In(struct roff_node *);
 static int      md_pre_It(struct roff_node *);
 static int      md_pre_Lk(struct roff_node *);
+static int      md_pre_Mt(struct roff_node *);
 static int      md_pre_Nd(struct roff_node *);
 static int      md_pre_Nm(struct roff_node *);
 static int      md_pre_No(struct roff_node *);
@@ -211,7 +213,7 @@ static      const struct md_act md_acts[MDOC_MAX + 1] = {
        { NULL, NULL, md_post_Lb, NULL, NULL }, /* Lb */
        { NULL, md_pre_Pp, NULL, NULL, NULL }, /* Lp */
        { NULL, md_pre_Lk, NULL, NULL, NULL }, /* Lk */
-       { NULL, md_pre_raw, md_post_raw, "<", ">" }, /* Mt */
+       { NULL, md_pre_Mt, NULL, NULL, NULL }, /* Mt */
        { md_cond_body, md_pre_word, md_post_word, "{", "}" }, /* Brq */
        { md_cond_body, md_pre_word, md_post_word, "{", "}" }, /* Bro */
        { NULL, NULL, NULL, NULL, NULL }, /* Brc */
@@ -1279,39 +1281,64 @@ md_post_Lb(struct roff_node *n)
                outflags |= MD_br;
 }
 
+static void
+md_uri(const char *s)
+{
+       while (*s != '\0') {
+               if (strchr("%()<>", *s) != NULL) {
+                       printf("%%%2.2hhX", *s);
+                       outcount += 3;
+               } else {
+                       putchar(*s);
+                       outcount++;
+               }
+               s++;
+       }
+}
+
 static int
 md_pre_Lk(struct roff_node *n)
 {
        const struct roff_node *link, *descr;
-       const unsigned char *s;
 
        if ((link = n->child) == NULL)
                return 0;
 
-       if ((descr = link->next) != NULL) {
-               md_rawword("[");
-               outflags &= ~MD_spc;
-               while (descr != NULL) {
-                       md_word(descr->string);
-                       descr = descr->next;
-               }
-               outflags &= ~MD_spc;
-               md_rawword("](");
-       } else
-               md_rawword("<");
+       descr = link->next == NULL ? link : link->next;
+       md_rawword("[");
+       outflags &= ~MD_spc;
+       do {
+               md_word(descr->string);
+               descr = link->next == NULL ? NULL : descr->next;
+       } while (descr != NULL);
+       outflags &= ~MD_spc;
+       md_rawword("](");
+       md_uri(link->string);
+       outflags &= ~MD_spc;
+       md_rawword(")");
+       return 0;
+}
 
-       for (s = link->string; *s != '\0'; s++) {
-               if (strchr("%()<>", *s) != NULL) {
-                       printf("%%%2.2hhX", *s);
-                       outcount += 3;
-               } else {
-                       putchar(*s);
+static int
+md_pre_Mt(struct roff_node *n)
+{
+       const struct roff_node *nch;
+
+       md_rawword("[");
+       outflags &= ~MD_spc;
+       for (nch = n->child; nch != NULL; nch = nch->next)
+               md_word(nch->string);
+       outflags &= ~MD_spc;
+       md_rawword("](mailto:");
+       for (nch = n->child; nch != NULL; nch = nch->next) {
+               md_uri(nch->string);
+               if (nch->next != NULL) {
+                       putchar(' ');
                        outcount++;
                }
        }
-
        outflags &= ~MD_spc;
-       md_rawword(link->next == NULL ? ">" : ")");
+       md_rawword(")");
        return 0;
 }
 

diff --git a/regress/mdoc/Aq/author.out_markdown b/regress/mdoc/Aq/author.out_markdown
index 292eb5c573a960fc21372043859cd319107ec8ed..85803ee7ef39ca4aa7a4015af5649e002df558c5 100644 (file)
--- a/regress/mdoc/Aq/author.out_markdown
+++ b/regress/mdoc/Aq/author.out_markdown
@@ -6,11 +6,11 @@ AQ-AUTHOR(1) - General Commands Manual
 
 # DESCRIPTION
 
-Name &lt;<addr>&gt; Name &lt;<addr>&gt;
+Name &lt;[addr](mailto:addr)&gt; Name &lt;[addr](mailto:addr)&gt;
 
 # AUTHORS
 
-Name &lt;<addr>&gt;  
-Name &lt;<addr>&gt;
+Name &lt;[addr](mailto:addr)&gt;  
+Name &lt;[addr](mailto:addr)&gt;
 
 OpenBSD - November 19, 2014

diff --git a/regress/mdoc/Lk/noarg.out_markdown b/regress/mdoc/Lk/noarg.out_markdown
index f27e0895f4cc124069b7a3cf0fa35752e86746d4..16c01df2f81c566ac40f3d300f42d18890063fbf 100644 (file)
--- a/regress/mdoc/Lk/noarg.out_markdown
+++ b/regress/mdoc/Lk/noarg.out_markdown
@@ -9,7 +9,7 @@ LK-NOARG(1) - General Commands Manual
 two arguments
 [mandoc](http://mdocml.bsd.lv/)
 one argument
-<http://www.openbsd.org/>
+[http://www.openbsd.org/](http://www.openbsd.org/)
 no argument
 end of test document
 

diff --git a/regress/mdoc/Mt/simple.out_markdown b/regress/mdoc/Mt/simple.out_markdown
index 0b85b45d4a6abaaefea434b9c5c9e9da1ac4e112..78c21be45e570a615351171951204445d1421caa 100644 (file)
--- a/regress/mdoc/Mt/simple.out_markdown
+++ b/regress/mdoc/Mt/simple.out_markdown
@@ -7,9 +7,9 @@ MT-SIMPLE(1) - General Commands Manual
 # DESCRIPTION
 
 Please send mail to
-<schwarze@openbsd.org>.
+[schwarze@openbsd.org](mailto:schwarze@openbsd.org).
 
 Do not send mail to
-<~>.
+[~](mailto:~).
 
 OpenBSD - February 17, 2010

diff --git a/regress/mdoc/Rs/allch.out_markdown b/regress/mdoc/Rs/allch.out_markdown
index afc6488f8191711832628228f49fc54a29349e91..64b891cc303868f59d1fa2ba289da9920841df3a 100644 (file)
--- a/regress/mdoc/Rs/allch.out_markdown
+++ b/regress/mdoc/Rs/allch.out_markdown
@@ -18,7 +18,7 @@ author name,
 report name,
 number of journal,
 volume number,
-<uniform resource locator>,
+[uniform resource locator](uniform resource locator),
 page number,
 institutional author,
 city name,
@@ -40,7 +40,7 @@ author name,
 report name,
 number of journal,
 volume number,
-<uniform resource locator>,
+[uniform resource locator](uniform resource locator),
 page number,
 institutional author,
 city name,