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Fix crash in target_name decoding #91

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Merged
merged 2 commits into from
Mar 17, 2023
+50 −1
Merged

Fix crash in target_name decoding #91

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353a9ee
Fix potential crash when no target name is present
simo5 Mar 17, 2023
a0e9739
Add test to check target_name can be NULL
simo5 Mar 17, 2023
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4 changes: 3 additions & 1 deletion src/ntlm.c
View file
Original file line number Diff line number Diff line change
@@ -325,7 +325,9 @@ static int ntlm_decode_u16l_str_hdr(struct ntlm_ctx *ctx,
safefree(out);
} else {
/* make sure to terminate output string */
out[outlen] = '\0';
if (out) {
out[outlen] = '\0';
}
}

*str = out;
47 changes: 47 additions & 0 deletions tests/ntlmssptest.c
View file
Original file line number Diff line number Diff line change
@@ -3132,6 +3132,48 @@ int test_debug(void)
return 0;
}

int test_bad_challenge(struct ntlm_ctx *ctx)
{
struct ntlm_buffer challenge = { T_ServerChallenge, 8 };
struct ntlm_buffer message = { 0 };
struct wire_chal_msg *msg;
uint32_t type;
uint32_t flags;
char *target_name = NULL;
uint8_t chal[8];
struct ntlm_buffer rchallenge = { chal, 8 };
int ret;

/* check we can decode encode/decode NULL target_name */
flags = T_NTLMv1.ChallengeFlags &
~(NTLMSSP_TARGET_TYPE_SERVER | NTLMSSP_TARGET_TYPE_DOMAIN);
flags |= NTLMSSP_NEGOTIATE_UNICODE;

ret = ntlm_encode_chal_msg(ctx, flags, NULL,
&challenge, NULL, &message);
if (ret) return ret;

/* Doctor the message to set back NTLMSSP_TARGET_TYPE_SERVER */
msg = (struct wire_chal_msg *)message.data;
msg->neg_flags |= NTLMSSP_TARGET_TYPE_SERVER;

ret = ntlm_decode_msg_type(ctx, &message, &type);
if (ret) return ret;
if (type != 2) return EINVAL;

ret = ntlm_decode_chal_msg(ctx, &message, &flags, &target_name,
&rchallenge, NULL);
if (ret) return ret;

if (target_name != NULL) {
ret = EINVAL;
free(target_name);
}
free(message.data);

return ret;
}

int main(int argc, const char *argv[])
{
struct ntlm_ctx *ctx;
@@ -3367,6 +3409,11 @@ int main(int argc, const char *argv[])
fprintf(stderr, "Test: %s\n", (ret ? "FAIL":"SUCCESS"));
if (ret) gret++;

fprintf(stderr, "Test Bad Challenge Message\n");
ret = test_bad_challenge(ctx);
fprintf(stderr, "Test: %s\n", (ret ? "FAIL":"SUCCESS"));
if (ret) gret++;

fprintf(stderr, "Test Acquired cred from with no name\n");
ret = test_ACQ_NO_NAME();
fprintf(stderr, "Test: %s\n", (ret ? "FAIL":"SUCCESS"));