> On Aug 24, 2020, at 2:05 PM, Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote: > > > > Le lun. 24 août 2020 à 20:11, Nick Terrell <terrelln@xxxxxx> a écrit : >>> 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. > > SZ_1G is the biggest I can go to get the kernel to boot. With SZ_2G it won't boot. Strange… I don’t quite know what is going on then. Thanks for the fix! You can add: Reviewed-By: Nick Terrell <terrelln@xxxxxx> Best, Nick >> 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. > > Great, thanks. > > Cheers, > -Paul > >> -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 > >
