[librsvg/librsvg-2.44] (#496): Ensure all lengths and angles parse as finite numbers

[Federico Mena Quintero <federico src gnome org>]

commit aa3902b49ad3519baca0f70e3389d457ab1668c7
Author: Federico Mena Quintero <federico gnome org>
Date:   Sat Aug 17 13:54:56 2019 -0500

    (#496): Ensure all lengths and angles parse as finite numbers
    
    The example crasher, found via fuzzing, yields an <svg width="BIGNUM">
    which rust-cssparser puts as an Infinity in an f32 value.  This ends
    up being in a non-invertible Cairo matrix, which panics.
    
    We need to catch all such cases early, so we run all parsed numbers
    through finite_f32() right as they come out of rust-cssparser.
    
    Thanks to Bastien Orivel for the fuzz-testing runs!
    
    Fixes https://gitlab.gnome.org/GNOME/librsvg/issues/496

 rsvg_internals/src/length.rs  | 9 ++++-----
 rsvg_internals/src/parsers.rs | 4 ++--
 2 files changed, 6 insertions(+), 7 deletions(-)
---
diff --git a/rsvg_internals/src/length.rs b/rsvg_internals/src/length.rs
index d9caaf2d..cdbedc2d 100644
--- a/rsvg_internals/src/length.rs
+++ b/rsvg_internals/src/length.rs
@@ -3,8 +3,7 @@ use std::f64::consts::*;
 
 use drawing_ctx::ViewParams;
 use error::*;
-use parsers::Parse;
-use parsers::ParseError;
+use parsers::{Parse, ParseError, finite_f32};
 use state::ComputedValues;
 
 #[derive(Debug, PartialEq, Copy, Clone)]
@@ -150,13 +149,13 @@ impl Length {
 
             match *token {
                 Token::Number { value, .. } => Length {
-                    length: f64::from(value),
+                    length: f64::from(finite_f32(value)?),
                     unit: LengthUnit::Default,
                     dir,
                 },
 
                 Token::Percentage { unit_value, .. } => Length {
-                    length: f64::from(unit_value),
+                    length: f64::from(finite_f32(unit_value)?),
                     unit: LengthUnit::Percent,
                     dir,
                 },
@@ -164,7 +163,7 @@ impl Length {
                 Token::Dimension {
                     value, ref unit, ..
                 } => {
-                    let value = f64::from(value);
+                    let value = f64::from(finite_f32(value)?);
 
                     match unit.as_ref() {
                         "em" => Length {
diff --git a/rsvg_internals/src/parsers.rs b/rsvg_internals/src/parsers.rs
index 5eae2591..752335f8 100644
--- a/rsvg_internals/src/parsers.rs
+++ b/rsvg_internals/src/parsers.rs
@@ -130,12 +130,12 @@ pub fn angle_degrees(parser: &mut Parser<'_, '_>) -> Result<f64, ParseError> {
             .map_err(|_| ParseError::new("expected angle"))?;
 
         match *token {
-            Token::Number { value, .. } => f64::from(value),
+            Token::Number { value, .. } => f64::from(finite_f32(value).map_err(|_| ParseError::new("expected 
finite value"))?),
 
             Token::Dimension {
                 value, ref unit, ..
             } => {
-                let value = f64::from(value);
+                let value = f64::from(finite_f32(value).map_err(|_| ParseError::new("expected finite 
value"))?);
 
                 match unit.as_ref() {
                     "deg" => value,