memcmp: Introduce and use consttime_memeq

[secnet.git] / transform.c

diff --git a/transform.c b/transform.c
index 5497711c228b7b4b0e2395739c5b00a0b97886e2..012f6186a5072516b3069a70f40c658a4c2adfd7 100644 (file)
--- a/transform.c
+++ b/transform.c
@@ -19,7 +19,6 @@
 
 struct transform {
     closure_t cl;
-    uint32_t line;
     struct transform_if ops;
     uint32_t max_seq_skew;
 };
@@ -69,12 +68,19 @@ static bool_t transform_setkey(void *sst, uint8_t *key, int32_t keylen)
     return True;
 }
 
+static bool_t transform_valid(void *sst)
+{
+    struct transform_inst *ti=sst;
+
+    return ti->keyed;
+}
+
 static void transform_delkey(void *sst)
 {
     struct transform_inst *ti=sst;
 
-    memset(&ti->cryptkey,0,sizeof(ti->cryptkey));
-    memset(&ti->mackey,0,sizeof(ti->mackey));
+    FILLZERO(ti->cryptkey);
+    FILLZERO(ti->mackey);
     ti->keyed=False;
 }
 
@@ -172,6 +178,10 @@ static uint32_t transform_reverse(void *sst, struct buffer_if *buf,
        return 1;
     }
 
+    if (buf->size < 4 + 16 + 16) {
+       *errmsg="msg too short";
+       return 1;
+    }
 
     /* CBC */
     memset(iv,0,16);
@@ -182,6 +192,7 @@ static uint32_t transform_reverse(void *sst, struct buffer_if *buf,
     /* Assert bufsize is multiple of blocksize */
     if (buf->size&0xf) {
        *errmsg="msg not multiple of cipher blocksize";
+       return 1;
     }
     serpent_encrypt(&ti->cryptkey,iv,iv);
     for (n=buf->start; n<buf->start+buf->size; n+=16)
@@ -209,7 +220,7 @@ static uint32_t transform_reverse(void *sst, struct buffer_if *buf,
        serpent_encrypt(&ti->mackey,macplain,macacc);
     }
     serpent_encrypt(&ti->mackey,macacc,macacc);
-    if (memcmp(macexpected,macacc,16)!=0) {
+    if (!consttime_memeq(macexpected,macacc,16)!=0) {
        *errmsg="invalid MAC";
        return 1;
     }
@@ -243,7 +254,7 @@ static uint32_t transform_reverse(void *sst, struct buffer_if *buf,
     } else {
        /* Too much skew */
        *errmsg="seqnum: too much skew";
-       return 1;
+       return 2;
     }
     
     return 0;
@@ -253,7 +264,7 @@ static void transform_destroy(void *sst)
 {
     struct transform_inst *st=sst;
 
-    memset(st,0,sizeof(*st)); /* Destroy key material */
+    FILLZERO(*st); /* Destroy key material */
     free(st);
 }
 
@@ -267,6 +278,7 @@ static struct transform_inst_if *transform_create(void *sst)
 
     ti->ops.st=ti;
     ti->ops.setkey=transform_setkey;
+    ti->ops.valid=transform_valid;
     ti->ops.delkey=transform_delkey;
     ti->ops.forwards=transform_forward;
     ti->ops.reverse=transform_reverse;