From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
linux-f2fs-devel@lists.sourceforge.net,
Daniel Rosenberg <drosen@google.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
syzkaller-bugs@googlegroups.com,
syzbot+05139c4039d0679e19ff@syzkaller.appspotmail.com
Subject: Re: [PATCH] f2fs: reject CASEFOLD inode flag without casefold feature
Date: Thu, 08 Oct 2020 15:26:45 -0400 [thread overview]
Message-ID: <87ft6oldsa.fsf@collabora.com> (raw)
In-Reply-To: <20201008191522.1948889-1-ebiggers@kernel.org> (Eric Biggers's message of "Thu, 8 Oct 2020 12:15:22 -0700")
Eric Biggers <ebiggers@kernel.org> writes:
> From: Eric Biggers <ebiggers@google.com>
>
> syzbot reported:
>
> general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
> CPU: 0 PID: 6860 Comm: syz-executor835 Not tainted 5.9.0-rc8-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:utf8_casefold+0x43/0x1b0 fs/unicode/utf8-core.c:107
> [...]
> Call Trace:
> f2fs_init_casefolded_name fs/f2fs/dir.c:85 [inline]
> __f2fs_setup_filename fs/f2fs/dir.c:118 [inline]
> f2fs_prepare_lookup+0x3bf/0x640 fs/f2fs/dir.c:163
> f2fs_lookup+0x10d/0x920 fs/f2fs/namei.c:494
> __lookup_hash+0x115/0x240 fs/namei.c:1445
> filename_create+0x14b/0x630 fs/namei.c:3467
> user_path_create fs/namei.c:3524 [inline]
> do_mkdirat+0x56/0x310 fs/namei.c:3664
> do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [...]
>
> The problem is that an inode has F2FS_CASEFOLD_FL set, but the
> filesystem doesn't have the casefold feature flag set, and therefore
> super_block::s_encoding is NULL.
>
> Fix this by making sanity_check_inode() reject inodes that have
> F2FS_CASEFOLD_FL when the filesystem doesn't have the casefold feature.
>
> Reported-by: syzbot+05139c4039d0679e19ff@syzkaller.appspotmail.com
> Fixes: 2c2eb7a300cd ("f2fs: Support case-insensitive file name lookups")
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Looks good. For the record, this is fixed on ext4 already.
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2020-10-08 19:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 14:59 general protection fault in utf8_casefold syzbot
2020-10-08 19:15 ` [PATCH] f2fs: reject CASEFOLD inode flag without casefold feature Eric Biggers
2020-10-08 19:26 ` Gabriel Krisman Bertazi [this message]
2020-10-09 1:30 ` Chao Yu
2020-10-09 2:40 ` general protection fault in utf8_casefold syzbot
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