Merge pull request #2446 from jow-/CVE-2016-2381

perl: securely handle duplicate environment variables [CVE-2016-2381]

lang/perl/Makefile

@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2006-2015 OpenWrt.org
+# Copyright (C) 2006-2016 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=perl
 PKG_VERSION:=5.22.1
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE_URL:=ftp://ftp.cpan.org/pub/CPAN/src/5.0 \
 		http://www.cpan.org/src/5.0 \

lang/perl/patches/901-CVE-2016-2381.patch

@@ -0,0 +1,102 @@
+From: Tony Cook <tony@develop-help.com>
+Date: Wed, 27 Jan 2016 00:52:15 +0000 (+1100)
+Subject: remove duplicate environment variables from environ
+X-Git-Url: http://perl5.git.perl.org/perl.git/commitdiff_plain/ae37b791a73a9e78dedb89fb2429d2628cf58076
+
+remove duplicate environment variables from environ
+
+If we see duplicate environment variables while iterating over
+environ[]:
+
+a) make sure we use the same value in %ENV that getenv() returns.
+
+Previously on a duplicate, %ENV would have the last entry for the name
+from environ[], but a typical getenv() would return the first entry.
+
+Rather than assuming all getenv() implementations return the first entry
+explicitly call getenv() to ensure they agree.
+
+b) remove duplicate entries from environ
+
+Previously if there was a duplicate definition for a name in environ[]
+setting that name in %ENV could result in an unsafe value being passed
+to a child process, so ensure environ[] has no duplicates.
+
+CVE-2016-2381
+---
+
+--- a/perl.c
++++ b/perl.c
+@@ -4298,23 +4298,70 @@ S_init_postdump_symbols(pTHX_ int argc,
+ 	}
+ 	if (env) {
+ 	  char *s, *old_var;
++          STRLEN nlen;
+ 	  SV *sv;
++          HV *dups = newHV();
++
+ 	  for (; *env; env++) {
+ 	    old_var = *env;
+ 
+ 	    if (!(s = strchr(old_var,'=')) || s == old_var)
+ 		continue;
++            nlen = s - old_var;
+ 
+ #if defined(MSDOS) && !defined(DJGPP)
+ 	    *s = '\0';
+ 	    (void)strupr(old_var);
+ 	    *s = '=';
+ #endif
+-	    sv = newSVpv(s+1, 0);
+-	    (void)hv_store(hv, old_var, s - old_var, sv, 0);
++            if (hv_exists(hv, old_var, nlen)) {
++                const char *name = savepvn(old_var, nlen);
++
++                /* make sure we use the same value as getenv(), otherwise code that
++                   uses getenv() (like setlocale()) might see a different value to %ENV
++                 */
++                sv = newSVpv(PerlEnv_getenv(name), 0);
++
++                /* keep a count of the dups of this name so we can de-dup environ later */
++                if (hv_exists(dups, name, nlen))
++                    ++SvIVX(*hv_fetch(dups, name, nlen, 0));
++                else
++                    (void)hv_store(dups, name, nlen, newSViv(1), 0);
++
++                Safefree(name);
++            }
++            else {
++                sv = newSVpv(s+1, 0);
++            }
++	    (void)hv_store(hv, old_var, nlen, sv, 0);
+ 	    if (env_is_not_environ)
+ 	        mg_set(sv);
+ 	  }
++          if (HvKEYS(dups)) {
++              /* environ has some duplicate definitions, remove them */
++              HE *entry;
++              hv_iterinit(dups);
++              while ((entry = hv_iternext_flags(dups, 0))) {
++                  STRLEN nlen;
++                  const char *name = HePV(entry, nlen);
++                  IV count = SvIV(HeVAL(entry));
++                  IV i;
++                  SV **valp = hv_fetch(hv, name, nlen, 0);
++
++                  assert(valp);
++
++                  /* try to remove any duplicate names, depending on the
++                   * implementation used in my_setenv() the iteration might
++                   * not be necessary, but let's be safe.
++                   */
++                  for (i = 0; i < count; ++i)
++                      my_setenv(name, 0);
++
++                  /* and set it back to the value we set $ENV{name} to */
++                  my_setenv(name, SvPV_nolen(*valp));
++              }
++          }
++          SvREFCNT_dec_NN(dups);
+       }
+ #endif /* USE_ENVIRON_ARRAY */
+ #endif /* !PERL_MICRO */