On 02/24/2018 10:03 AM, Maciej S. Szmigiero wrote:
CCP RSA implementation uses a hardware input buffer which size depends only
on the current RSA key length. Key modulus and a message to be processed
is then copied to this buffer based on their own lengths.
Since the price for providing too long input data is a buffer overflow and
there already has been a case when this has happened let's better reject
such oversized input data and log an error message in this case so we know
what is going on.
Signed-off-by: Maciej S. Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/crypto/ccp/ccp-ops.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/crypto/ccp/ccp-ops.c b/drivers/crypto/ccp/ccp-ops.c
index 406b95329b3d..517aeee30abf 100644
--- a/drivers/crypto/ccp/ccp-ops.c
+++ b/drivers/crypto/ccp/ccp-ops.c
@@ -1770,10 +1770,6 @@ static int ccp_run_rsa_cmd(struct ccp_cmd_queue *cmd_q, struct ccp_cmd *cmd)
if (!rsa->exp || !rsa->mod || !rsa->src || !rsa->dst)
return -EINVAL;
- memset(&op, 0, sizeof(op));
- op.cmd_q = cmd_q;
- op.jobid = CCP_NEW_JOBID(cmd_q->ccp);
-
/* The RSA modulus must precede the message being acted upon, so
* it must be copied to a DMA area where the message and the
* modulus can be concatenated. Therefore the input buffer
@@ -1785,6 +1781,26 @@ static int ccp_run_rsa_cmd(struct ccp_cmd_queue *cmd_q, struct ccp_cmd *cmd)
o_len = 32 * ((rsa->key_size + 255) / 256);
i_len = o_len * 2;
+ if (rsa->mod_len > o_len) {
+ dev_err(cmd_q->ccp->dev,
+ "RSA modulus of %u bytes too large for key size of %u bits\n",
+ (unsigned int)rsa->mod_len,
+ (unsigned int)rsa->key_size);
+ return -EINVAL;
+ }
+
+ if (rsa->src_len > o_len) {
+ dev_err(cmd_q->ccp->dev,
+ "RSA data of %u bytes too large for key size of %u bits\n",
+ (unsigned int)rsa->src_len,
+ (unsigned int)rsa->key_size);
+ return -EINVAL;
+ }
We've talked about this, and we believe that a more central fix is
warranted. I intend to post another patch tomorrow that should address
this problem.
+
+ memset(&op, 0, sizeof(op));
+ op.cmd_q = cmd_q;
+ op.jobid = CCP_NEW_JOBID(cmd_q->ccp);
+
sb_count = 0;
if (cmd_q->ccp->vdata->version < CCP_VERSION(5, 0)) {
/* sb_count is the number of storage block slots required
