From: Eric Biggers <ebiggers@kernel.org>
To: Chao Yu <chao@kernel.org>
Cc: jaegeuk@kernel.org, linux-kernel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix uninit-value in f2fs_lookup
Date: Fri, 25 Sep 2020 10:14:36 -0700 [thread overview]
Message-ID: <20200925171436.GC3315208@gmail.com> (raw)
In-Reply-To: <20200925151926.2658-1-chao@kernel.org>
On Fri, Sep 25, 2020 at 11:19:26PM +0800, Chao Yu wrote:
> From: Chao Yu <yuchao0@huawei.com>
>
> As syzbot reported:
>
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x21c/0x280 lib/dump_stack.c:118
> kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
> __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
> f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
> lookup_open fs/namei.c:3082 [inline]
> open_last_lookups fs/namei.c:3177 [inline]
> path_openat+0x2729/0x6a90 fs/namei.c:3365
> do_filp_open+0x2b8/0x710 fs/namei.c:3395
> do_sys_openat2+0xa88/0x1140 fs/open.c:1168
> do_sys_open fs/open.c:1184 [inline]
> __do_compat_sys_openat fs/open.c:1242 [inline]
> __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240
> __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240
> do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
> __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
> do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
> do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
> entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
>
> In f2fs_lookup(), @res_page could be used before being initialized,
> because in __f2fs_find_entry(), once F2FS_I(dir)->i_current_depth was
> been fuzzed to zero, then @res_page will never be initialized, causing
> this kmsan warning, relocating @res_page initialization place to fix
> this bug.
>
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
> fs/f2fs/dir.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index 703cf8e21fc0..83630341ffa3 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -357,16 +357,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
> unsigned int max_depth;
> unsigned int level;
>
> + *res_page = NULL;
> +
> if (f2fs_has_inline_dentry(dir)) {
> - *res_page = NULL;
> de = f2fs_find_in_inline_dir(dir, fname, res_page);
> goto out;
> }
>
> - if (npages == 0) {
> - *res_page = NULL;
> + if (npages == 0)
> goto out;
> - }
>
> max_depth = F2FS_I(dir)->i_current_depth;
> if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
Can't the assignment to *res_page below be removed too?
for (level = 0; level < max_depth; level++) {
*res_page = NULL;
de = find_in_level(dir, level, fname, res_page);
if (de || IS_ERR(*res_page))
break;
}
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WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers <ebiggers@kernel.org>
To: Chao Yu <chao@kernel.org>
Cc: jaegeuk@kernel.org, linux-kernel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix uninit-value in f2fs_lookup
Date: Fri, 25 Sep 2020 10:14:36 -0700 [thread overview]
Message-ID: <20200925171436.GC3315208@gmail.com> (raw)
In-Reply-To: <20200925151926.2658-1-chao@kernel.org>
On Fri, Sep 25, 2020 at 11:19:26PM +0800, Chao Yu wrote:
> From: Chao Yu <yuchao0@huawei.com>
>
> As syzbot reported:
>
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x21c/0x280 lib/dump_stack.c:118
> kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
> __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
> f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
> lookup_open fs/namei.c:3082 [inline]
> open_last_lookups fs/namei.c:3177 [inline]
> path_openat+0x2729/0x6a90 fs/namei.c:3365
> do_filp_open+0x2b8/0x710 fs/namei.c:3395
> do_sys_openat2+0xa88/0x1140 fs/open.c:1168
> do_sys_open fs/open.c:1184 [inline]
> __do_compat_sys_openat fs/open.c:1242 [inline]
> __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240
> __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240
> do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
> __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
> do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
> do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
> entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
>
> In f2fs_lookup(), @res_page could be used before being initialized,
> because in __f2fs_find_entry(), once F2FS_I(dir)->i_current_depth was
> been fuzzed to zero, then @res_page will never be initialized, causing
> this kmsan warning, relocating @res_page initialization place to fix
> this bug.
>
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
> fs/f2fs/dir.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index 703cf8e21fc0..83630341ffa3 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -357,16 +357,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
> unsigned int max_depth;
> unsigned int level;
>
> + *res_page = NULL;
> +
> if (f2fs_has_inline_dentry(dir)) {
> - *res_page = NULL;
> de = f2fs_find_in_inline_dir(dir, fname, res_page);
> goto out;
> }
>
> - if (npages == 0) {
> - *res_page = NULL;
> + if (npages == 0)
> goto out;
> - }
>
> max_depth = F2FS_I(dir)->i_current_depth;
> if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
Can't the assignment to *res_page below be removed too?
for (level = 0; level < max_depth; level++) {
*res_page = NULL;
de = find_in_level(dir, level, fname, res_page);
if (de || IS_ERR(*res_page))
break;
}
next prev parent reply other threads:[~2020-09-25 17:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-25 15:19 [f2fs-dev] [PATCH] f2fs: fix uninit-value in f2fs_lookup Chao Yu
2020-09-25 15:19 ` Chao Yu
2020-09-25 17:14 ` Eric Biggers [this message]
2020-09-25 17:14 ` [f2fs-dev] " Eric Biggers
2020-09-25 23:31 ` Chao Yu
2020-09-25 23:31 ` Chao Yu
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