lib/digsig: additional sanity checks against badly formated key payload
Added sanity checks for possible wrongly formatted key payload data:
- minimum key payload size
- zero modulus length
- corrected upper key payload boundary.
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Reviewed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/lib/digsig.c b/lib/digsig.c
index fd2402f..5d840ac 100644
--- a/lib/digsig.c
+++ b/lib/digsig.c
@@ -105,6 +105,10 @@
down_read(&key->sem);
ukp = key->payload.data;
+
+ if (ukp->datalen < sizeof(*pkh))
+ goto err1;
+
pkh = (struct pubkey_hdr *)ukp->data;
if (pkh->version != 1)
@@ -117,7 +121,7 @@
goto err1;
datap = pkh->mpi;
- endp = datap + ukp->datalen;
+ endp = ukp->data + ukp->datalen;
for (i = 0; i < pkh->nmpi; i++) {
unsigned int remaining = endp - datap;
@@ -128,7 +132,8 @@
mblen = mpi_get_nbits(pkey[0]);
mlen = (mblen + 7)/8;
- err = -ENOMEM;
+ if (mlen == 0)
+ goto err;
out1 = kzalloc(mlen, GFP_KERNEL);
if (!out1)