block/sed: Check received header lengths

Add a buffer size check against discovery and response header lengths
before we loop over their buffers.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Reviewed-by: Scott Bauer <scott.bauer@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/sed-opal.c b/block/sed-opal.c
index d3d6db2877b98232ceb00ea6273f7f9015d3c230..4fc4d7b441d5ea66023a41a85c162c9d64561324 100644 (file)
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -411,10 +411,17 @@ static int opal_discovery0_end(struct opal_dev *dev)
        const struct d0_header *hdr = (struct d0_header *)dev->resp;
        const u8 *epos = dev->resp, *cpos = dev->resp;
        u16 comid = 0;
+       u32 hlen = be32_to_cpu(hdr->length);
 
-       print_buffer(dev->resp, be32_to_cpu(hdr->length));
+       print_buffer(dev->resp, hlen);
 
-       epos += be32_to_cpu(hdr->length); /* end of buffer */
+       if (hlen > IO_BUFFER_LENGTH - sizeof(*hdr)) {
+               pr_warn("Discovery length overflows buffer (%zu+%u)/%u\n",
+                       sizeof(*hdr), hlen, IO_BUFFER_LENGTH);
+               return -EFAULT;
+       }
+
+       epos += hlen; /* end of buffer */
        cpos += sizeof(*hdr); /* current position on buffer */
 
        while (cpos < epos && supported) {
@@ -784,6 +791,7 @@ static int response_parse(const u8 *buf, size_t length,
        int total;
        ssize_t token_length;
        const u8 *pos;
+       u32 clen, plen, slen;
 
        if (!buf)
                return -EFAULT;
@@ -795,17 +803,16 @@ static int response_parse(const u8 *buf, size_t length,
        pos = buf;
        pos += sizeof(*hdr);
 
-       pr_debug("Response size: cp: %d, pkt: %d, subpkt: %d\n",
-                be32_to_cpu(hdr->cp.length),
-                be32_to_cpu(hdr->pkt.length),
-                be32_to_cpu(hdr->subpkt.length));
-
-       if (hdr->cp.length == 0 || hdr->pkt.length == 0 ||
-           hdr->subpkt.length == 0) {
-               pr_err("Bad header length. cp: %d, pkt: %d, subpkt: %d\n",
-                      be32_to_cpu(hdr->cp.length),
-                      be32_to_cpu(hdr->pkt.length),
-                      be32_to_cpu(hdr->subpkt.length));
+       clen = be32_to_cpu(hdr->cp.length);
+       plen = be32_to_cpu(hdr->pkt.length);
+       slen = be32_to_cpu(hdr->subpkt.length);
+       pr_debug("Response size: cp: %u, pkt: %u, subpkt: %u\n",
+                clen, plen, slen);
+
+       if (clen == 0 || plen == 0 || slen == 0 ||
+           slen > IO_BUFFER_LENGTH - sizeof(*hdr)) {
+               pr_err("Bad header length. cp: %u, pkt: %u, subpkt: %u\n",
+                      clen, plen, slen);
                print_buffer(pos, sizeof(*hdr));
                return -EINVAL;
        }
@@ -814,7 +821,7 @@ static int response_parse(const u8 *buf, size_t length,
                return -EFAULT;
 
        iter = resp->toks;
-       total = be32_to_cpu(hdr->subpkt.length);
+       total = slen;
        print_buffer(pos, total);
        while (total > 0) {
                if (pos[0] <= TINY_ATOM_BYTE) /* tiny atom */