[master] 2d8909407 vmod_blob flexelinting round 2

[Nils Goroll]

commit 2d8909407cad5e0c93d931024fa3e736062bdf5a
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Tue Mar 10 13:06:36 2020 +0100

    vmod_blob flexelinting round 2

diff --git a/lib/libvmod_blob/hex.c b/lib/libvmod_blob/hex.c
index 8c2bf1d28..b95e45e90 100644
--- a/lib/libvmod_blob/hex.c
+++ b/lib/libvmod_blob/hex.c
@@ -135,7 +135,7 @@ hex_decode(const enum encoding dec, blob_dest_t buf,
 
 	if (len == 0)
 		return (0);
-	if (n > 0 && len > n)
+	if (n >= 0 && len > (size_t)n)
 		len = n;
 
 	if (((len+1) >> 1) > buflen) {
diff --git a/lib/libvmod_blob/vmod_blob.c b/lib/libvmod_blob/vmod_blob.c
index b99bab762..0c46106bc 100644
--- a/lib/libvmod_blob/vmod_blob.c
+++ b/lib/libvmod_blob/vmod_blob.c
@@ -532,12 +532,13 @@ vmod_sub(VRT_CTX, VCL_BLOB b, VCL_BYTES n, VCL_BYTES off)
 
 	assert(b->len > 0);
 
-	if (off < 0 || n < 0) {
-		ERR(ctx, "size and offset cannot be negative in blob.sub()");
+	if (off < 0 || n < 0 || off > SIZE_MAX || n > SIZE_MAX) {
+		ERR(ctx, "size or offset negative or out of range in blob.sub()");
 		return (NULL);
 	}
 
-	if (off + n > b->len) {
+	if ((size_t)off > b->len || (size_t)n > b->len ||
+	    (size_t)off + (size_t)n > b->len) {
 		VERR(ctx, "size %jd from offset %jd requires more bytes than "
 		    "blob length %zd in blob.sub()",
 		    (intmax_t)n, (intmax_t)off, b->len);