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

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perl: securely handle duplicate environment variables [CVE-2016-2381]
This commit is contained in:
champtar 2016-07-12 17:13:44 +02:00 committed by GitHub
commit 3f5ed39e40
2 changed files with 104 additions and 2 deletions
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4
lang/perl/Makefile
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@ -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 \

102
lang/perl/patches/901-CVE-2016-2381.patch Normal file
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@ -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 */