Messages in this thread | | | Subject | Re: [PATCH] f2fs: fix potential overflow in build_sit_info | From | Chao Yu <> | Date | Wed, 9 Aug 2017 18:23:12 +0800 |
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Sorry, please ignore this patch. :(
Thanks,
On 2017/8/9 18:09, Chao Yu wrote: > On a 32-bit system, below calculation may overflow the 32-bit unsigned > integer, allocating a buffer size that smaller than needed. A write on > the buffer will then trigger an out of boundary write. > 1. MAIN_SEGS(sbi) * sizeof(struct seg_entry) > 2. MAIN_SECS(sbi) * sizeof(struct sec_entry) > > Fixes this by doing type cast before calculating. > > This patch fixes CVE-2017-10662. > > Signed-off-by: Chao Yu <yuchao0@huawei.com> > --- > fs/f2fs/segment.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index 682ae68b9ef7..947674b5f466 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -2997,8 +2997,9 @@ static int build_sit_info(struct f2fs_sb_info *sbi) > > SM_I(sbi)->sit_info = sit_i; > > - sit_i->sentries = kvzalloc(MAIN_SEGS(sbi) * > - sizeof(struct seg_entry), GFP_KERNEL); > + sit_i->sentries = kvzalloc((unsigned long long)MAIN_SEGS(sbi) * > + (unsigned long long)sizeof(struct seg_entry), > + GFP_KERNEL); > if (!sit_i->sentries) > return -ENOMEM; > > @@ -3036,8 +3037,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi) > return -ENOMEM; > > if (sbi->segs_per_sec > 1) { > - sit_i->sec_entries = kvzalloc(MAIN_SECS(sbi) * > - sizeof(struct sec_entry), GFP_KERNEL); > + sit_i->sec_entries = kvzalloc( > + (unsigned long long)MAIN_SECS(sbi) * > + (unsigned long long)sizeof(struct sec_entry), > + GFP_KERNEL); > if (!sit_i->sec_entries) > return -ENOMEM; > } >
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