Probable bug causes SEGFAULT due to access to pointers in
uninitialized EVP_CIPHER_CTX structure given to EVP_CipherInit_ex
function by PKCS5_pbe2_set function, when using PEM_write_PKCS8PrivateKey
function to save encrypted private key into file like this:
FILE *f;
EVP_PKEY *pkey;
/* initialisation of f and pkey... */
...
PEM_write_PKCS8PrivateKey(f, pkey, EVP_des_ede3_cbc(),
"blaah", 5, NULL, NULL);
Debug log
-------------------------------------------------------
Breakpoint 2, PEM_write_PKCS8PrivateKey (fp=0x414bae94, x=0x414acfe8,
enc=0x8129980, kstr=0x414a8ff8 "blaah", klen=5, cb=0, u=0x0)
at pem_pk8.c:208
208 return do_pk8pkey_fp(fp, x, 0, -1, enc, kstr, klen, cb,
u);
(gdb) p enc
$1 = (EVP_CIPHER *) 0x8129980
(gdb) p *enc
$2 = {nid = 44, block_size = 8, key_len = 24, iv_len = 8, flags = 2,
init = 0x808fb10 <des_ede3_init_key>,
do_cipher = 0x808f830 <des_ede_cbc_cipher>, cleanup = 0, ctx_size = 384,
set_asn1_parameters = 0x8092780 <EVP_CIPHER_set_asn1_iv>,
get_asn1_parameters = 0x80926e0 <EVP_CIPHER_get_asn1_iv>, ctrl = 0,
app_data = 0x0}
(gdb) p *x
$3 = {type = 6, save_type = 6, references = 1, pkey = {ptr = 0x414b4fac
"",
rsa = 0x414b4fac, dsa = 0x414b4fac, dh = 0x414b4fac}, save_parameters
= 1,
attributes = 0x0}
(gdb) c
Continuing.
Breakpoint 1, PKCS5_pbe2_set (cipher=0x8129980, iter=0, salt=0x0,
saltlen=0)
at p5_pbev2.c:90
90 X509_ALGOR *scheme = NULL, *kalg = NULL, *ret = NULL;
(gdb) n
94 PBKDF2PARAM *kdf = NULL;
(gdb) n
95 PBE2PARAM *pbe2 = NULL;
(gdb) n
96 ASN1_OCTET_STRING *osalt = NULL;
(gdb) p *cipher
$4 = {nid = 44, block_size = 8, key_len = 24, iv_len = 8, flags = 2,
init = 0x808fb10 <des_ede3_init_key>,
do_cipher = 0x808f830 <des_ede_cbc_cipher>, cleanup = 0, ctx_size = 384,
set_asn1_parameters = 0x8092780 <EVP_CIPHER_set_asn1_iv>,
get_asn1_parameters = 0x80926e0 <EVP_CIPHER_get_asn1_iv>, ctrl = 0,
app_data = 0x0}
(gdb) n
99 alg_nid = EVP_CIPHER_type(cipher);
(gdb) n
100 if(alg_nid == NID_undef) {
(gdb) n
105 obj = OBJ_nid2obj(alg_nid);
(gdb) n
107 if(!(pbe2 = PBE2PARAM_new())) goto merr;
(gdb) n
110 scheme = pbe2->encryption;
(gdb) n
112 scheme->algorithm = obj;
(gdb) n
113 if(!(scheme->parameter = ASN1_TYPE_new())) goto merr;
(gdb) n
116 if (RAND_pseudo_bytes(iv, EVP_CIPHER_iv_length(cipher)) <
0)
(gdb) n
120 EVP_CipherInit_ex(&ctx, cipher, NULL, NULL, iv, 0);
(gdb) s
EVP_CipherInit_ex (ctx=0x415ea7e4, cipher=0x8129980, impl=0x0, key=0x0,
iv=0x415ea7d4 "<EB><C2><A2><DE><C0>\035h%\004<A8>^A\023", enc=0) at
evp_enc.c:88
88 if (enc == -1)
(gdb) p *ctx
$5 = {cipher = 0x2, engine = 0x414e0ffc, encrypt = 0, buf_len = 0,
oiv = "\0\0\0\0\0\0\0\0\210<A4>\022\b0<A8>^A",
iv = "\225|\t\b\\<A8>^A\210<A4>\022\b\0\0\0",
buf =
"||\t\b\0\n\023\b<B6>\0\0\0<D0>\001\0\0\024\0\0\0\b\0\0\0l\002\0\0`<A8>^A",
num = 134839370, app_data = 0x415ea85c, key_len = 135439496, flags = 0,
cipher_data = 0x8097c2c, final_used = 135465472, block_mask = 1,
final =
"\020\0\0\0<AC><CF>\t\b<F0><CF>MA<F8>\017NA\220<A8>^AT^\t\b\210<A4>\022\b`\002\0"}
(gdb) n
92 if (enc)
(gdb) n
94 ctx->encrypt = enc;
(gdb) n
100 if (ctx->engine && ctx->cipher && (!cipher ||
(gdb) l
95 }
96 /* Whether it's nice or not, "Inits" can be used on
"Final"'d contexts
97 * so this context may already have an ENGINE! Try to
avoid releasing
98 * the previous handle, re-querying for an ENGINE, and
having a
99 * reinitialisation, when it may all be unecessary. */
100 if (ctx->engine && ctx->cipher && (!cipher ||
101 (cipher && (cipher->nid ==
ctx->cipher->nid))))
102 goto skip_to_init;
103 if (cipher)
104 {
(gdb) p *ctx
$6 = {cipher = 0x2, engine = 0x414e0ffc, encrypt = 0, buf_len = 0,
oiv = "\0\0\0\0\0\0\0\0\210<A4>\022\b0<A8>^A",
iv = "\225|\t\b\\<A8>^A\210<A4>\022\b\0\0\0",
buf =
"||\t\b\0\n\023\b<B6>\0\0\0<D0>\001\0\0\024\0\0\0\b\0\0\0l\002\0\0`<A8>^A",
num = 134839370, app_data = 0x415ea85c, key_len = 135439496, flags = 0,
cipher_data = 0x8097c2c, final_used = 135465472, block_mask = 1,
final =
"\020\0\0\0<AC><CF>\t\b<F0><CF>MA<F8>\017NA\220<A8>^AT^\t\b\210<A4>\022\b`\002\0"}
(gdb) p cipher
$7 = (EVP_CIPHER *) 0x8129980
(gdb) p ctx->cipher
$8 = (EVP_CIPHER *) 0x2
(gdb) n
Program received signal SIGSEGV, Segmentation fault.
0x0808e1d2 in EVP_CipherInit_ex (ctx=0x415ea7e4, cipher=0x8129980,
impl=0x0,
key=0x0, iv=0x415ea7d4 "<EB><C2><A2><DE><C0>\035h%\004<A8>^A\023",
enc=0) at evp_enc.c:100
100 if (ctx->engine && ctx->cipher && (!cipher ||
(gdb) bt
#0 0x0808e1d2 in EVP_CipherInit_ex (ctx=0x415ea7e4, cipher=0x8129980,
impl=0x0, key=0x0, iv=0x415ea7d4 "<EB><C2><A2><DE><C0>\035h%\004<A8>^A\023", enc=0)
at evp_enc.c:100
#1 0x0809ea84 in PKCS5_pbe2_set (cipher=0x8129980, iter=0, salt=0x0,
saltlen=0) at p5_pbev2.c:120
#2 0x080b1eeb in PKCS8_encrypt (pbe_nid=-1, cipher=0x8129980,
pass=0x414a8ff8 "blaah", passlen=5, salt=0x0, saltlen=0, iter=0,
p8inf=0x414c4fec) at p12_p8e.c:76
#3 0x080a04a8 in do_pk8pkey (bp=0x414c2fc0, x=0x414acfe8, isder=0,
nid=-1,
enc=0x8129980, kstr=0x414a8ff8 "blaah", klen=5, cb=0, u=0x0)
at pem_pk8.c:138
#4 0x080a08de in do_pk8pkey_fp (fp=0x414bae94, x=0x414acfe8, isder=0,
nid=-1,
enc=0x8129980, kstr=0x414a8ff8 "blaah", klen=5, cb=0, u=0x0)
at pem_pk8.c:221
#5 0x080a084b in PEM_write_PKCS8PrivateKey (fp=0x414bae94, x=0x414acfe8,
enc=0x8129980, kstr=0x414a8ff8 "blaah", klen=5, cb=0, u=0x0)
at pem_pk8.c:208
#6 0x0804fba6 in gen_privkey (boss=0x41106fb8) at privkey.c:27
#7 0x08054179 in _st_thread_main () at sched.c:621
-------------------------------------------------------
Code that triggered this:
-------------------------------------------------------
void *gen_privkey(void *boss)
{
STACK* centres;
AS_CentreData *centre;
EVP_PKEY *pkey, *pub = NULL;
RSA *rsa = NULL;
FILE *f;
char *pass;
int i, j, state, *doing_genkey;
const EVP_CIPHER *cipher;
cipher = EVP_des_ede3_cbc();
doing_genkey = boss_genkey_data(boss, &pass);
fprintf(stderr, "parool on '%s'\n", pass);
if (!(pkey = EVP_PKEY_new()) ||
!(pub = EVP_PKEY_new()) ||
!(rsa = RSA_generate_key(1024, 0x10001, RSA_genkey_cb, NULL)) ||
!EVP_PKEY_assign_RSA(pkey, rsa) ||
!(rsa = RSAPublicKey_dup(rsa)) ||
!EVP_PKEY_assign_RSA(pub, rsa) || (rsa = NULL) ||
open_file(&f, "temp_proxy_key.pem", "wb") ||
/* SEGFAULT happens in EVP_CipherInit_ex, when pass != NULL */
!close_file(f, PEM_write_PKCS8PrivateKey(f, pkey,
pass ? cipher : NULL, pass, pass ? strlen(pass) : 0, NULL,
NULL) &&
PEM_write_PUBKEY(f, pub)) ||
rename_file("temp_proxy_key.pem", "proxy_key.pem")) {
EVP_PKEY_free(pkey);
EVP_PKEY_free(pub);
RSA_free(rsa);
boss_estack(boss, PROXY_ERR_CREATE_PRIVATE_KEY,
"create private key failed");
} else {
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