Hello David Howells,
This is a semi-automatic email about new static checker warnings.
The patch 8c76d79393cc: "PKCS#7: Verify internal certificate chain"
from Jul 1, 2014, leads to the following Smatch complaint:
crypto/asymmetric_keys/pkcs7_verify.c:200 pkcs7_verify_sig_chain()
error: we previously assumed 'x509->issuer' could be null (see line
193)
crypto/asymmetric_keys/pkcs7_verify.c
192
193 if (x509->issuer)
^^^^^^^^^^^^
Check.
194 pr_debug("- issuer %s\n", x509->issuer);
195 if (x509->authority)
196 pr_debug("- authkeyid %s\n", x509->authority);
197
198 if (!x509->authority ||
199 (x509->subject &&
200 strcmp(x509->subject, x509->issuer) == 0)) {
^^^^^^^^^^^^
Unchecked dereference. But maybe a non-NULL ->subject implies ->issuer
is non-NULL?
201 /* If there's no authority certificate
specified, then
202 * the certificate must be self-signed and is
the root
203 * of the chain. Likewise if the cert is its
own
204 * authority.
205 */
206 pr_debug("- no auth?\n");
207 if (x509->raw_subject_size !=
x509->raw_issuer_size ||
208 memcmp(x509->raw_subject, x509->raw_issuer,
209 x509->raw_issuer_size) != 0)
210 return 0;
211
212 ret = x509_check_signature(x509->pub, x509);
213 if (ret < 0)
214 return ret;
215 x509->signer = x509;
216 pr_debug("- self-signed\n");
217 return 0;
218 }
219
220 /* Look through the X.509 certificates in the PKCS#7
message's
221 * list to see if the next one is there.
222 */
223 pr_debug("- want %s\n", x509->authority);
224 for (p = pkcs7->certs; p; p = p->next) {
225 pr_debug("- cmp [%u] %s\n", p->index,
p->fingerprint);
226 if (p->raw_subject_size ==
x509->raw_issuer_size &&
227 strcmp(p->fingerprint, x509->authority) ==
0 &&
228 memcmp(p->raw_subject, x509->raw_issuer,
229 x509->raw_issuer_size) == 0)
230 goto found_issuer;
231 }
232
233 /* We didn't find the root of this chain */
234 pr_debug("- top\n");
235 return 0;
236
237 found_issuer:
238 pr_debug("- issuer %s\n", p->subject);
^^^^^^
Also this looks like it should be "subject" instead of "issuer" but
maybe they are the same?
239 if (p->seen) {
240 pr_warn("Sig %u: X.509 chain contains loop\n",
241 sinfo->index);
regards,
dan carpenter
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