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Subject[PATCH v2 1/2] lib: decompress_unzstd: Limit output size
Date
The zstd decompression code, as it is right now, will have internal
values overflow on 32-bit systems when the output size is bigger than
1 GiB.

Until someone smarter than me can figure out how to fix the zstd code
properly, limit the destination buffer size to 1 GiB, which should be
enough for everybody, in order to make it usable on 32-bit systems.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Nick Terrell <terrelln@fb.com>
---

Notes:
v2: Change limit to 1 GiB

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..414517baedb0 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_1G; /* should be big enough, right? */

if (fill == NULL && flush == NULL)
/*
--
2.28.0
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