branch master updated: Fix afl-fuzz error

[Gavin D. Smith]

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gavin pushed a commit to branch master
in repository texinfo.

The following commit(s) were added to refs/heads/master by this push:
     new caea2ec  Fix afl-fuzz error
caea2ec is described below

commit caea2ecf9a11b050c5a2e565c35d6e60818807a2
Author: Gavin Smith <gavinsmith0123@gmail.com>
AuthorDate: Thu May 6 20:12:20 2021 +0100

    Fix afl-fuzz error
    
    * info/info-utils.c (copy_input_to_output): Avoid calling
    copy_converting with negative argument in case of malformed
    input file.  Report from Nathaniel Beaver for file generated
    by afl-fuzz.
---
 ChangeLog         | 9 +++++++++
 info/info-utils.c | 7 ++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index d63be26..1090ebf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2021-05-06  Gavin Smith  <gavinsmith0123@gmail.com>
+
+       Fix afl-fuzz error
+
+       * info/info-utils.c (copy_input_to_output): Avoid calling
+       copy_converting with negative argument in case of malformed
+       input file.  Report from Nathaniel Beaver for file generated
+       by afl-fuzz.
+
 2021-05-04  Per Bothner  <per@bothner.com>
 
        * js/info.js (updater.navigate): Relative movement without node links.
diff --git a/info/info-utils.c b/info/info-utils.c
index d39620a..998243f 100644
--- a/info/info-utils.c
+++ b/info/info-utils.c
@@ -997,7 +997,12 @@ copy_input_to_output (long n)
                   else if (first_anchor < (inptr-input_start) + bytes_left)
                     {
                       /* Convert enough to pass the first anchor in input. */
-                      bytes_to_convert = first_anchor - (inptr-input_start) + 
1;
+                      bytes_to_convert = first_anchor - (inptr-input_start)+1;
+                      if (bytes_to_convert < 0)
+                        {
+                          bytes_to_convert = bytes_left;
+                          anchor_to_adjust = 0;
+                        }
                     }
                 }