> On Aug 21, 2020, at 9:29 AM, Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote: > > The zstd decompression code, as it is right now, will have internal > values overflow on 32-bit systems when the output size is LONG_MAX. > > Until someone smarter than me can figure out how to fix the zstd code > properly, limit the destination buffer size to 512 MiB, which should be > enough for everybody, in order to make it usable on 32-bit systems. Can you bump the size up to 2GB? I suspect the problem inside of zstd is an off-by-one error or something similar, so getting closer to the limit shouldn't be a problem. I’d feel more comfortable with 2GB, since kernels can get pretty large. Hmm, zstd shouldn’t be overflowing that value. I’m currently preparing a patch to updating the version of zstd in the kernel, and using upstream directly. I will add a test upstream in 32-bit mode to ensure that we don’t overflow a 32-bit size_t, so this will be fixed after the update. -Nick > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx> > --- > lib/decompress_unzstd.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/lib/decompress_unzstd.c b/lib/decompress_unzstd.c > index 0ad2c15479ed..e1c03b1eaa6e 100644 > --- a/lib/decompress_unzstd.c > +++ b/lib/decompress_unzstd.c > @@ -77,6 +77,7 @@ > > #include <linux/decompress/mm.h> > #include <linux/kernel.h> > +#include <linux/sizes.h> > #include <linux/zstd.h> > > /* 128MB is the maximum window size supported by zstd. */ > @@ -179,7 +180,7 @@ static int INIT __unzstd(unsigned char *in_buf, long in_len, > size_t ret; > > if (out_len == 0) > - out_len = LONG_MAX; /* no limit */ > + out_len = SZ_512M; /* should be big enough, right? */ > > if (fill == NULL && flush == NULL) > /* > -- > 2.28.0 >
