double64_init: Check psf->sf.channels against upper bound

This prevents division by zero later in the code.

While the trivial case to catch this (i.e. sf.channels < 1) has already
been covered, a crafted file may report a number of channels that is
so high (i.e. > INT_MAX/sizeof(double)) that it "somehow" gets
miscalculated to zero (if this makes sense) in the determination of the
blockwidth. Since we only support a limited number of channels anyway,
make sure to check here as well.

CVE-2017-14634

Change-Id: Ifee1ff6c9af452f38725f4b599eae4ac069b93b5
Closes: https://github.com/erikd/libsndfile/issues/318
Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>

diff --git a/src/double64.c b/src/double64.c
index b318ea8..78dfef7 100644 (file)
--- a/src/double64.c
+++ b/src/double64.c
@@ -91,7 +91,7 @@ int
 double64_init  (SF_PRIVATE *psf)
 {      static int double64_caps ;
 
-       if (psf->sf.channels < 1)
+       if (psf->sf.channels < 1 || psf->sf.channels > SF_MAX_CHANNELS)
        {       psf_log_printf (psf, "double64_init : internal error : channels = %d\n", psf->sf.channels) ;
                return SFE_INTERNAL ;
                } ;