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-rw-r--r--lib/mpi/mpicoder.c18
1 files changed, 8 insertions, 10 deletions
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index 350abaf4bee7..9c6f6b986682 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -81,7 +81,7 @@ MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
{
const uint8_t *buffer = xbuffer;
int i, j;
- unsigned nbits, nbytes, nlimbs, nread = 0;
+ unsigned nbits, nbytes, nlimbs;
mpi_limb_t a;
MPI val = NULL;
@@ -94,9 +94,14 @@ MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
return ERR_PTR(-EINVAL);
}
buffer += 2;
- nread = 2;
nbytes = DIV_ROUND_UP(nbits, 8);
+ if (nbytes + 2 > *ret_nread) {
+ printk("MPI: mpi larger than buffer nread=%d ret_nread=%d\n",
+ *ret_nread + 1, *ret_nread);
+ return ERR_PTR(-EINVAL);
+ }
+
nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
val = mpi_alloc(nlimbs);
if (!val)
@@ -109,12 +114,6 @@ MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
for (; j > 0; j--) {
a = 0;
for (; i < BYTES_PER_MPI_LIMB; i++) {
- if (++nread > *ret_nread) {
- printk
- ("MPI: mpi larger than buffer nread=%d ret_nread=%d\n",
- nread, *ret_nread);
- goto leave;
- }
a <<= 8;
a |= *buffer++;
}
@@ -122,8 +121,7 @@ MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
val->d[j - 1] = a;
}
-leave:
- *ret_nread = nread;
+ *ret_nread = nbytes + 2;
return val;
}
EXPORT_SYMBOL_GPL(mpi_read_from_buffer);