113 lines
3.7 KiB
Diff
113 lines
3.7 KiB
Diff
From ae37b791a73a9e78dedb89fb2429d2628cf58076 Mon Sep 17 00:00:00 2001
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From: Tony Cook <tony@develop-help.com>
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Date: Wed, 27 Jan 2016 11:52:15 +1100
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Subject: [PATCH] remove duplicate environment variables from environ
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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If we see duplicate environment variables while iterating over
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environ[]:
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a) make sure we use the same value in %ENV that getenv() returns.
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Previously on a duplicate, %ENV would have the last entry for the name
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from environ[], but a typical getenv() would return the first entry.
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Rather than assuming all getenv() implementations return the first entry
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explicitly call getenv() to ensure they agree.
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b) remove duplicate entries from environ
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Previously if there was a duplicate definition for a name in environ[]
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setting that name in %ENV could result in an unsafe value being passed
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to a child process, so ensure environ[] has no duplicates.
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CVE-2016-2381
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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perl.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++--
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1 file changed, 49 insertions(+), 2 deletions(-)
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diff --git a/perl.c b/perl.c
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index 4a324c6..5c71fd0 100644
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--- a/perl.c
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+++ b/perl.c
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@@ -4329,23 +4329,70 @@ S_init_postdump_symbols(pTHX_ int argc, char **argv, char **env)
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}
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if (env) {
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char *s, *old_var;
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+ STRLEN nlen;
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SV *sv;
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+ HV *dups = newHV();
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+
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for (; *env; env++) {
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old_var = *env;
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if (!(s = strchr(old_var,'=')) || s == old_var)
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continue;
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+ nlen = s - old_var;
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#if defined(MSDOS) && !defined(DJGPP)
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*s = '\0';
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(void)strupr(old_var);
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*s = '=';
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#endif
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- sv = newSVpv(s+1, 0);
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- (void)hv_store(hv, old_var, s - old_var, sv, 0);
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+ if (hv_exists(hv, old_var, nlen)) {
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+ const char *name = savepvn(old_var, nlen);
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+
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+ /* make sure we use the same value as getenv(), otherwise code that
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+ uses getenv() (like setlocale()) might see a different value to %ENV
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+ */
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+ sv = newSVpv(PerlEnv_getenv(name), 0);
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+
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+ /* keep a count of the dups of this name so we can de-dup environ later */
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+ if (hv_exists(dups, name, nlen))
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+ ++SvIVX(*hv_fetch(dups, name, nlen, 0));
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+ else
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+ (void)hv_store(dups, name, nlen, newSViv(1), 0);
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+
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+ Safefree(name);
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+ }
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+ else {
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+ sv = newSVpv(s+1, 0);
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+ }
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+ (void)hv_store(hv, old_var, nlen, sv, 0);
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if (env_is_not_environ)
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mg_set(sv);
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}
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+ if (HvKEYS(dups)) {
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+ /* environ has some duplicate definitions, remove them */
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+ HE *entry;
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+ hv_iterinit(dups);
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+ while ((entry = hv_iternext_flags(dups, 0))) {
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+ STRLEN nlen;
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+ const char *name = HePV(entry, nlen);
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+ IV count = SvIV(HeVAL(entry));
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+ IV i;
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+ SV **valp = hv_fetch(hv, name, nlen, 0);
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+
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+ assert(valp);
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+
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+ /* try to remove any duplicate names, depending on the
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+ * implementation used in my_setenv() the iteration might
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+ * not be necessary, but let's be safe.
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+ */
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+ for (i = 0; i < count; ++i)
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+ my_setenv(name, 0);
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+
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+ /* and set it back to the value we set $ENV{name} to */
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+ my_setenv(name, SvPV_nolen(*valp));
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+ }
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+ }
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+ SvREFCNT_dec_NN(dups);
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}
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#endif /* USE_ENVIRON_ARRAY */
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#endif /* !PERL_MICRO */
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--
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2.5.0
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