svn commit: r358750 - stable/12/lib/libfetch

[Ed Maste]

Author: emaste
Date: Sun Mar  8 18:08:45 2020
New Revision: 358750
URL: https://svnweb.freebsd.org/changeset/base/358750

Log:
  MFC r357579: libfetch: disallow invalid escape sequences
  
  Per RFC1738 escape is "% hex hex"; other sequences do not form a valid URL.
  
  Suggested by:	Matthew Dillon
  Reviewed by:	Matthew Dillon
  Sponsored by:	The FreeBSD Foundation

Modified:
  stable/12/lib/libfetch/fetch.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/lib/libfetch/fetch.c
==============================================================================
--- stable/12/lib/libfetch/fetch.c	Sun Mar  8 18:07:33 2020	(r358749)
+++ stable/12/lib/libfetch/fetch.c	Sun Mar  8 18:08:45 2020	(r358750)
@@ -325,6 +325,9 @@ fetch_pctdecode(char *dst, const char *src, size_t dle
 		    (d2 = fetch_hexval(s[2])) >= 0 && (d1 > 0 || d2 > 0)) {
 			c = d1 << 4 | d2;
 			s += 2;
+		} else if (s[0] == '%') {
+			/* Invalid escape sequence. */
+			return (NULL);
 		} else {
 			c = *s;
 		}