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- From 7d65f89defb092b63bcbc5d98349fb222ca73b3c Mon Sep 17 00:00:00 2001
- From: Antonio Larrosa <larrosa@kde.org>
- Date: Mon, 6 Mar 2017 13:54:52 +0100
- Subject: [PATCH] Check for multiplication overflow in sfconvert
-
- Checks that a multiplication doesn't overflow when
- calculating the buffer size, and if it overflows,
- reduce the buffer size instead of failing.
-
- This fixes the 00192-audiofile-signintoverflow-sfconvert case
- in #41
- ---
- sfcommands/sfconvert.c | 34 ++++++++++++++++++++++++++++++++--
- 1 file changed, 32 insertions(+), 2 deletions(-)
-
- diff --git a/sfcommands/sfconvert.c b/sfcommands/sfconvert.c
- index 80a1bc4..970a3e4 100644
- --- a/sfcommands/sfconvert.c
- +++ b/sfcommands/sfconvert.c
- @@ -45,6 +45,33 @@ void printusage (void);
- void usageerror (void);
- bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid);
-
- +int firstBitSet(int x)
- +{
- + int position=0;
- + while (x!=0)
- + {
- + x>>=1;
- + ++position;
- + }
- + return position;
- +}
- +
- +#ifndef __has_builtin
- +#define __has_builtin(x) 0
- +#endif
- +
- +int multiplyCheckOverflow(int a, int b, int *result)
- +{
- +#if (defined __GNUC__ && __GNUC__ >= 5) || ( __clang__ && __has_builtin(__builtin_mul_overflow))
- + return __builtin_mul_overflow(a, b, result);
- +#else
- + if (firstBitSet(a)+firstBitSet(b)>31) // int is signed, so we can't use 32 bits
- + return true;
- + *result = a * b;
- + return false;
- +#endif
- +}
- +
- int main (int argc, char **argv)
- {
- if (argc == 2)
- @@ -323,8 +350,11 @@ bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid)
- {
- int frameSize = afGetVirtualFrameSize(infile, trackid, 1);
-
- - const int kBufferFrameCount = 65536;
- - void *buffer = malloc(kBufferFrameCount * frameSize);
- + int kBufferFrameCount = 65536;
- + int bufferSize;
- + while (multiplyCheckOverflow(kBufferFrameCount, frameSize, &bufferSize))
- + kBufferFrameCount /= 2;
- + void *buffer = malloc(bufferSize);
-
- AFframecount totalFrames = afGetFrameCount(infile, AF_DEFAULT_TRACK);
- AFframecount totalFramesWritten = 0;
- --
- 2.11.0
-
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