libgcrypt/mpi: Fix possible NULL dereference

The code in gcry_mpi_scan() assumes that buffer is not NULL, but there
is no explicit check for that, so we add one.

Fixes: CID 73757
Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/grub-core/lib/libgcrypt/mpi/mpicoder.c b/grub-core/lib/libgcrypt/mpi/mpicoder.c
index 7ecad27b23a7d9548bab3dba6a84de9bfb0d5463..6fe389165328f6e7808bf3ece3fa4eb7c0dd2576 100644 (file)
--- a/grub-core/lib/libgcrypt/mpi/mpicoder.c
+++ b/grub-core/lib/libgcrypt/mpi/mpicoder.c
@@ -379,6 +379,9 @@ gcry_mpi_scan (struct gcry_mpi **ret_mpi, enum gcry_mpi_format format,
   unsigned int len;
   int secure = (buffer && gcry_is_secure (buffer));
 
+  if (!buffer)
+    return gcry_error (GPG_ERR_INV_ARG);
+
   if (format == GCRYMPI_FMT_SSH)
     len = 0;
   else