Am Fr 15. Jul 2016, 02:36:20, mikem@airspayce.com schrieb:
Show quoted text> Hi Steffen,
>
> thanks thats all good now.
>
Hi Mike,
while writing a test for IO::Socket::SSL I've noticed some very weird behavior, like unexpected changes in the control flow of the Perl program which seemed to be triggered by the ticket key callback. Turns out that these effects were caused by missing cleanups in the XS code, i.e. PUTBACK, FREETMPS and LEAVE :(
The attached patch resolves this issue. I've tested it with openssl versions 1.0.2g, 1.0.2c, 1.1.0 and 1.0.1. I don't expect any problems with other versions since the code is basically doing the same as before, only with proper cleanups at the right time.
Index: SSLeay.xs
===================================================================
--- SSLeay.xs (revision 478)
+++ SSLeay.xs (working copy)
@@ -1256,12 +1256,11 @@
){
dSP;
- int count;
+ int count,usable_rv_count;
SV *cb_func, *cb_data;
- SV *sv_name, *sv_key;
STRLEN svlen;
- unsigned char *key; /* key[0..15] aes, key[16..32] hmac */
- unsigned char *name;
+ unsigned char key[32]; /* key[0..15] aes, key[16..32] hmac */
+ unsigned char name[16];
SSL_CTX *ctx = SSL_get_SSL_CTX(ssl);
PR1("STARTED: tlsext_ticket_key_cb_invoke\n");
@@ -1274,6 +1273,7 @@
ENTER;
SAVETMPS;
PUSHMARK(SP);
+
XPUSHs(sv_2mortal(newSVsv(cb_data)));
if (!enc) {
@@ -1283,29 +1283,50 @@
/* call as getkey(data) -> (key,current_name) */
}
+ PUTBACK;
- PUTBACK;
count = call_sv( cb_func, G_ARRAY );
SPAGAIN;
- if (count>0) sv_name = POPs;
- if (count>1) sv_key = POPs;
- if (!enc && ( !count || !SvOK(sv_key) )) {
+ if (count>2)
+ croak("too much return values - only (name,key) should be returned");
+
+ usable_rv_count = 0;
+ if (count>0) {
+ SV *sname = POPs;
+ if (SvOK(sname)) {
+ unsigned char *pname = SvPV(sname,svlen);
+ if (svlen > 16)
+ croak("name must be at at most 16 bytes, got %d",svlen);
+ if (svlen == 0)
+ croak("name should not be empty");
+ memset(name, 0, 16);
+ memcpy(name,pname,svlen);
+ usable_rv_count++;
+ }
+ }
+ if (count>1) {
+ SV *skey = POPs;
+ if (SvOK(skey)) {
+ unsigned char *pkey = SvPV(skey,svlen);
+ if (svlen != 32)
+ croak("key must be exactly 32 random bytes, got %d",svlen);
+ memcpy(key,pkey,32);
+ usable_rv_count++;
+ }
+ }
+
+ PUTBACK;
+ FREETMPS;
+ LEAVE;
+
+ if (!enc && usable_rv_count == 0) {
TRACE(2,"no key returned for ticket");
return 0;
}
-
- if (count != 2)
+ if (usable_rv_count != 2)
croak("key functions needs to return (key,name)");
- key = SvPV(sv_key,svlen);
- if (svlen < 32)
- croak("key must be at least 32 random bytes, got %d",svlen);
- name = SvPV(sv_name,svlen);
- if (svlen != 16)
- croak("name should be exactly 16 characters, got %d",svlen);
- if (svlen == 0)
- croak("name should not be empty");
if (enc) {
/* encrypt ticket information with given key */
@@ -1312,18 +1333,14 @@
RAND_bytes(iv, 16);
EVP_EncryptInit_ex(ectx, EVP_aes_128_cbc(), NULL, key, iv);
HMAC_Init_ex(hctx,key+16,16,EVP_sha256(),NULL);
- memset(key_name, 0, 16);
- memcpy(key_name,name,svlen);
+ memcpy(key_name,name,16);
return 1;
+
} else {
- unsigned char new_name[16];
- memset(new_name, 0, sizeof(new_name));
- memcpy(new_name,name,svlen);
-
HMAC_Init_ex(hctx,key+16,16,EVP_sha256(),NULL);
EVP_DecryptInit_ex(ectx, EVP_aes_128_cbc(), NULL, key, iv);
- if (memcmp(new_name,key_name,16) == 0)
+ if (memcmp(name,key_name,16) == 0)
return 1; /* current key was used */
else
return 2; /* different key was used, need to be renewed */
