From c5f31c655bcc01b6da53b836ac951c1556245305 Mon Sep 17 00:00:00 2001
From: Zheng Yejian <zhengyejian1@huawei.com>
Date: Sat, 15 May 2021 22:06:31 +0800
Subject: [PATCH] acct: fix potential integer overflow in encode_comp_t()
Git-commit: c5f31c655bcc01b6da53b836ac951c1556245305
Patch-mainline: v6.2-rc1
References: git-fixes
The integer overflow is descripted with following codes:
> 317 static comp_t encode_comp_t(u64 value)
> 318 {
> 319 int exp, rnd;
......
> 341 exp <<= MANTSIZE;
> 342 exp += value;
> 343 return exp;
> 344 }
Currently comp_t is defined as type of '__u16', but the variable 'exp' is
type of 'int', so overflow would happen when variable 'exp' in line 343 is
greater than 65535.
Link: https://lkml.kernel.org/r/20210515140631.369106-3-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zhang Jinhao <zhangjinhao2@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
kernel/acct.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/acct.c b/kernel/acct.c
index 31b09cf7189c..010667ce6080 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -350,6 +350,8 @@ static comp_t encode_comp_t(u64 value)
exp++;
}
+ if (exp > (((comp_t) ~0U) >> MANTSIZE))
+ return (comp_t) ~0U;
/*
* Clean it up and polish it off.
*/
--
2.35.3