Add error checking for EVP_Digest* to snmpd(8).

ok martijn

diff --git a/usr.sbin/snmpd/usm.c b/usr.sbin/snmpd/usm.c
index 40356c8..d9129c7 100644 (file)
--- a/usr.sbin/snmpd/usm.c
+++ b/usr.sbin/snmpd/usm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: usm.c,v 1.22 2022/01/05 11:00:49 tb Exp $     */
+/*     $OpenBSD: usm.c,v 1.23 2022/01/05 16:41:42 tb Exp $     */
 
 /*
  * Copyright (c) 2012 GeNUA mbH
@@ -720,7 +720,10 @@ usm_passwd2key(const EVP_MD *md, char *passwd, int *maxlen)
 
        if ((ctx = EVP_MD_CTX_new()) == NULL)
                return NULL;
-       EVP_DigestInit(ctx, md);
+       if (!EVP_DigestInit(ctx, md)) {
+               EVP_MD_CTX_free(ctx);
+               return NULL;
+       }
        pw = (u_char *)passwd;
        for (count = 0; count < 1048576; count += 64) {
                c = pwbuf;
@@ -729,9 +732,15 @@ usm_passwd2key(const EVP_MD *md, char *passwd, int *maxlen)
                                pw = (u_char *)passwd;
                        *c++ = *pw++;
                }
-               EVP_DigestUpdate(ctx, pwbuf, 64);
+               if (!EVP_DigestUpdate(ctx, pwbuf, 64)) {
+                       EVP_MD_CTX_free(ctx);
+                       return NULL;
+               }
+       }
+       if (!EVP_DigestFinal(ctx, keybuf, &dlen)) {
+               EVP_MD_CTX_free(ctx);
+               return NULL;
        }
-       EVP_DigestFinal(ctx, keybuf, &dlen);
        EVP_MD_CTX_reset(ctx);
 
        /* Localize the key */
@@ -743,9 +752,13 @@ usm_passwd2key(const EVP_MD *md, char *passwd, int *maxlen)
            snmpd_env->sc_engineid_len);
        memcpy(pwbuf + dlen + snmpd_env->sc_engineid_len, keybuf, dlen);
 
-       EVP_DigestInit(ctx, md);
-       EVP_DigestUpdate(ctx, pwbuf, 2 * dlen + snmpd_env->sc_engineid_len);
-       EVP_DigestFinal(ctx, keybuf, &dlen);
+       if (!EVP_DigestInit(ctx, md) ||
+           !EVP_DigestUpdate(ctx, pwbuf,
+           2 * dlen + snmpd_env->sc_engineid_len) ||
+           !EVP_DigestFinal(ctx, keybuf, &dlen)) {
+               EVP_MD_CTX_free(ctx);
+               return NULL;
+       }
        EVP_MD_CTX_free(ctx);
 
        if (*maxlen > 0 && dlen > (unsigned)*maxlen)