The patch titled
Subject: acct: fix potential integer overflow in encode_comp_t()
has been added to the -mm mm-nonmm-unstable branch. Its filename is
acct-fix-potential-integer-overflow-in-encode_comp_t.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/acct-fix-potential-integer-overflow-in-encode_comp_t.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
Subject: acct: fix potential integer overflow in encode_comp_t()
Date: Sat, 15 May 2021 22:06:31 +0800
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@xxxxxxxxxx
Signed-off-by: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
Cc: Hanjun Guo <guohanjun@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Zhang Jinhao <zhangjinhao2@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/acct.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/acct.c~acct-fix-potential-integer-overflow-in-encode_comp_t
+++ a/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.
*/
_
Patches currently in -mm which might be from zhengyejian1@xxxxxxxxxx are
acct-fix-accuracy-loss-for-input-value-of-encode_comp_t.patch
acct-fix-potential-integer-overflow-in-encode_comp_t.patch
