[FFmpeg-devel] [PATCH 3/3] avcodec/sbrdsp_fixed: Fix integer overflow in shift in sbr_hf_g_filt_c()

Michael Niedermayer michael at niedermayer.cc
Wed Nov 1 15:00:20 EET 2017


Fixes: runtime error: shift exponent 66 is too large for 64-bit type 'long long'
Fixes: 3642/clusterfuzz-testcase-minimized-5443853801750528

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/sbrdsp_fixed.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/libavcodec/sbrdsp_fixed.c b/libavcodec/sbrdsp_fixed.c
index 896b2d75c6..a0ef6859f1 100644
--- a/libavcodec/sbrdsp_fixed.c
+++ b/libavcodec/sbrdsp_fixed.c
@@ -244,12 +244,14 @@ static void sbr_hf_g_filt_c(int (*Y)[2], const int (*X_high)[40][2],
     int64_t accu;
 
     for (m = 0; m < m_max; m++) {
-        int64_t r = 1LL << (22-g_filt[m].exp);
-        accu = (int64_t)X_high[m][ixh][0] * ((g_filt[m].mant + 0x40)>>7);
-        Y[m][0] = (int)((accu + r) >> (23-g_filt[m].exp));
+        if (22 - g_filt[m].exp < 61) {
+            int64_t r = 1LL << (22-g_filt[m].exp);
+            accu = (int64_t)X_high[m][ixh][0] * ((g_filt[m].mant + 0x40)>>7);
+            Y[m][0] = (int)((accu + r) >> (23-g_filt[m].exp));
 
-        accu = (int64_t)X_high[m][ixh][1] * ((g_filt[m].mant + 0x40)>>7);
-        Y[m][1] = (int)((accu + r) >> (23-g_filt[m].exp));
+            accu = (int64_t)X_high[m][ixh][1] * ((g_filt[m].mant + 0x40)>>7);
+            Y[m][1] = (int)((accu + r) >> (23-g_filt[m].exp));
+        }
     }
 }
 
-- 
2.14.2



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