Fix CVE-2022-46285: Infinite loop on unclosed comments

When reading XPM images from a file with libXpm 3.5.14 or older, if a
comment in the file is not closed (i.e. a C-style comment starts with
"/*" and is missing the closing "*/"), the ParseComment() function will
loop forever calling getc() to try to read the rest of the comment,
failing to notice that it has returned EOF, which may cause a denial of
service to the calling program.

Reported-by: Marco Ivaldi <raptor@0xdeadbeef.info>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/data.c b/src/data.c
index 898889c..bfad4ff 100644
--- a/src/data.c
+++ b/src/data.c
@@ -174,6 +174,10 @@ ParseComment(xpmData *data)
 		notend = 0;
 		Ungetc(data, *s, file);
 	    }
+	    else if (c == EOF) {
+		/* hit end of file before the end of the comment */
+		return XpmFileInvalid;
+	    }
 	}
 	return 0;
     }