[groff] 111/115: [troff]: Validate a font family before using it.

[G. Branden Robinson]

gbranden pushed a commit to branch branden-2022-06-01
in repository groff.

commit 1fea0c142fae929cce003d6e529e000687149735
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Thu May 25 05:35:25 2023 -0500

    [troff]: Validate a font family before using it.
    
    * src/roff/troff/env.cpp (is_family_valid): New function checks for all
      text styles (R, I, B, BI) and returns true only if the given family
      supports them all.
    
      (family_change): Call `is_family_valid()` on given argument.  If
      invalid, throw diagnostic and ignore `fam` request.
    
    * src/roff/troff/env.h (is_family_valid): Declare; make visible.
    
    * src/roff/troff/input.cpp (main): Call `is_family_valid()` on `-f`
      option argument.  Its invalidity is a fatal error.
    
    Fixes <https://savannah.gnu.org/bugs/?64115>.  Thanks to Dave
    Kemper for the report.
    
    Tested with:
    
    $ echo | ./build/test-groff -fZD -z
    troff: fatal error: 'ZD' is not a valid font family
    $ echo | ./build/test-groff -fH -z
    $ nl ./EXPERIMENTS/validate-family.groff
         1  .tm .fam=\n[.fam]
         2  .fam H
         3  .tm .fam=\n[.fam]
         4  .fam
         5  .tm .fam=\n[.fam]
         6  .fam ZD
         7  .fam BOGUS
         8  .tm .fam=\n[.fam]
         9  .fam
        10  .tm .fam=\n[.fam]
    $ ./build/test-groff ./EXPERIMENTS/validate-family.groff
    .fam=T
    .fam=H
    .fam=T
    troff:./EXPERIMENTS/validate-family.groff:6: error: 'ZD' is not a valid 
font family
    troff:./EXPERIMENTS/validate-family.groff:7: error: 'BOGUS' is not a valid 
font family
    .fam=T
    .fam=H
---
 ChangeLog                | 16 ++++++++++++++++
 src/roff/troff/env.cpp   | 20 ++++++++++++++++++++
 src/roff/troff/env.h     |  1 +
 src/roff/troff/input.cpp |  3 +++
 4 files changed, 40 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 364cff1ee..424bd44d1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2023-05-25  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [troff]: Validate a font family before trying to use it.
+
+       * src/roff/troff/env.cpp (is_family_valid): New function checks
+       for all text styles (R, I, B, BI) and returns true only if the
+       given family supports them all.
+       (family_change): Call `is_family_valid()` on given argument.
+       If invalid, throw diagnostic and ignore `fam` request.
+       * src/roff/troff/env.h (is_family_valid): Declare; make visible.
+       * src/roff/troff/input.cpp (main): Call `is_family_valid()` on
+       `-f` option argument.  Its invalidity is a fatal error.
+
+       Fixes <https://savannah.gnu.org/bugs/?64115>.  Thanks to Dave
+       Kemper for the report.
+
 2023-05-25  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * src/roff/troff/env.h (read_hyphen_file): Drop relic prototype
diff --git a/src/roff/troff/env.cpp b/src/roff/troff/env.cpp
index 4c64273ef..13dd10d09 100644
--- a/src/roff/troff/env.cpp
+++ b/src/roff/troff/env.cpp
@@ -1256,9 +1256,29 @@ void font_change()
   skip_line();
 }
 
+bool is_family_valid(const char *fam)
+{
+  // std::vector<const char *> styles{"R", "I", "B", "BI"}; // C++11
+  const size_t nstyles = 4;
+  const char *st[nstyles] = { "R", "I", "B", "BI" };
+  std::vector<const char *> styles(st, (st + nstyles));
+  std::vector<const char *>::iterator style;
+  // for (auto style : styles) // C++11
+  for (style = styles.begin(); style != styles.end(); style++)
+    if (!check_font(fam, *style))
+      return false;
+  return true;
+}
+
 void family_change()
 {
   symbol s = get_name();
+  if (s != 0 /* nullptr */)
+    if (!is_family_valid(s.contents())) {
+      error("'%1' is not a valid font family", s.contents());
+      skip_line();
+      return;
+    }
   curenv->set_family(s);
   skip_line();
 }
diff --git a/src/roff/troff/env.h b/src/roff/troff/env.h
index d98941914..8382d11ea 100644
--- a/src/roff/troff/env.h
+++ b/src/roff/troff/env.h
@@ -408,6 +408,7 @@ extern void pop_env();
 extern void push_env(int);
 
 void init_environments();
+bool is_family_valid(const char *);
 
 extern double spread_limit;
 
diff --git a/src/roff/troff/input.cpp b/src/roff/troff/input.cpp
index cbb8b1ca3..56c20f3eb 100644
--- a/src/roff/troff/input.cpp
+++ b/src/roff/troff/input.cpp
@@ -8333,6 +8333,9 @@ int main(int argc, char **argv)
        warning(WARN_FONT, "cannot mount font '%1' directed by 'DESC'"
                " file for device '%2'", font::font_name_table[i],
                device);
+  if (fflag && !(is_family_valid(default_family.contents())))
+      fatal("'%1' is not a valid font family",
+           default_family.contents());
   curdiv = topdiv = new top_level_diversion;
   if (nflag)
     topdiv->set_next_page_number(next_page_number);