[PATCHv4 3/4] block/sed: Check received header lengths

Jon Derrick
2017-02-15T21:46:20Z

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>
---
block/sed-opal.c | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/block/sed-opal.c b/block/sed-opal.c
index 00673cf..383d5d6 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -340,10 +340,17 @@ 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) {
@@ -713,6 +720,7 @@ 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;
@@ -724,17 +732,16 @@ 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;
}
@@ -743,7 +750,7 @@ 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 */
--
1.8.3.1