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>

1 files changed, 21 insertions, 14 deletions

diff --git a/block/sed-opal.c b/block/sed-opal.c
index d3d6db2877b9..4fc4d7b441d5 100644
--- 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 */