pam-ssh-agent: fix EDCSA crash

This commit is contained in:
Wout Mertens 2020-12-30 16:38:10 +01:00
parent e92cc61453
commit 76675a1f73
2 changed files with 54 additions and 0 deletions

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@ -24,6 +24,7 @@ stdenv.mkDerivation rec {
# Allow multiple colon-separated authorized keys files to be
# specified in the file= option.
./multiple-key-files.patch
./edcsa-crash-fix.patch
];
configureFlags = [

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@ -0,0 +1,53 @@
commit 1b0d9bcc5f5cd78b0bb1357d6a11da5d616ad26f
Author: Wout Mertens <Wout.Mertens@gmail.com>
Date: Thu Jun 11 18:08:13 2020 +0200
fix segfault when using ECDSA keys.
Author: Marc Deslauriers <marc.deslauriers@canonical.com>
Bug-Ubuntu: https://bugs.launchpad.net/bugs/1869512
diff --git a/ssh-ecdsa.c b/ssh-ecdsa.c
index 5b13b30..5bf29cc 100644
--- a/ssh-ecdsa.c
+++ b/ssh-ecdsa.c
@@ -46,7 +46,7 @@ ssh_ecdsa_sign(const Key *key, u_char **sigp, u_int *lenp,
u_int len, dlen;
Buffer b, bb;
#if OPENSSL_VERSION_NUMBER >= 0x10100005L
- BIGNUM *r, *s;
+ BIGNUM *r = NULL, *s = NULL;
#endif
if (key == NULL || key->type != KEY_ECDSA || key->ecdsa == NULL) {
@@ -137,20 +137,27 @@ ssh_ecdsa_verify(const Key *key, const u_char *signature, u_int signaturelen,
/* parse signature */
if ((sig = ECDSA_SIG_new()) == NULL)
- pamsshagentauth_fatal("ssh_ecdsa_verify: DSA_SIG_new failed");
+ pamsshagentauth_fatal("ssh_ecdsa_verify: ECDSA_SIG_new failed");
pamsshagentauth_buffer_init(&b);
pamsshagentauth_buffer_append(&b, sigblob, len);
#if OPENSSL_VERSION_NUMBER < 0x10100005L
if ((pamsshagentauth_buffer_get_bignum2_ret(&b, sig->r) == -1) ||
(pamsshagentauth_buffer_get_bignum2_ret(&b, sig->s) == -1))
+ pamsshagentauth_fatal("ssh_ecdsa_verify:"
+ "pamsshagentauth_buffer_get_bignum2_ret failed");
#else
- DSA_SIG_get0(sig, &r, &s);
+ if ((r = BN_new()) == NULL)
+ pamsshagentauth_fatal("ssh_ecdsa_verify: BN_new failed");
+ if ((s = BN_new()) == NULL)
+ pamsshagentauth_fatal("ssh_ecdsa_verify: BN_new failed");
if ((pamsshagentauth_buffer_get_bignum2_ret(&b, r) == -1) ||
(pamsshagentauth_buffer_get_bignum2_ret(&b, s) == -1))
-#endif
pamsshagentauth_fatal("ssh_ecdsa_verify:"
"pamsshagentauth_buffer_get_bignum2_ret failed");
+ if (ECDSA_SIG_set0(sig, r, s) != 1)
+ pamsshagentauth_fatal("ssh_ecdsa_verify: ECDSA_SIG_set0 failed");
+#endif
/* clean up */
memset(sigblob, 0, len);