lib/mpi: Fix SG miter leak

In mpi_read_raw_from_sgl we may leak the SG miter resouces after
reading the leading zeroes.  This patch fixes this by stopping the
iteration once the leading zeroes have been read.

Fixes: 127827b9c295 ("lib/mpi: Do not do sg_virt")
Reported-by: Nicolai Stange <nicstange@gmail.com>
Tested-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index c6272ae2015e706634e04eef16af75eca0f95091..5a0f75a3bf01c1b259fb125fbe7266c186d83a71 100644 (file)
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -363,6 +363,9 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
                lzeros = 0;
        }
 
+       miter.consumed = lzeros;
+       sg_miter_stop(&miter);
+
        nbytes -= lzeros;
        nbits = nbytes * 8;
        if (nbits > MAX_EXTERN_MPI_BITS) {
@@ -390,7 +393,10 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
        z = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
        z %= BYTES_PER_MPI_LIMB;
 
-       for (;;) {
+       while (sg_miter_next(&miter)) {
+               buff = miter.addr;
+               len = miter.length;
+
                for (x = 0; x < len; x++) {
                        a <<= 8;
                        a |= *buff++;
@@ -400,12 +406,6 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int nbytes)
                        }
                }
                z += x;
-
-               if (!sg_miter_next(&miter))
-                       break;
-
-               buff = miter.addr;
-               len = miter.length;
        }
 
        return val;