From: Eric Biggers ebiggers@google.com
[ Upstream commit f6322f3f1212e005e7e6aa82ceb62be53030a64b ]
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 Reviewed-by: Gabriel Krisman Bertazi krisman@collabora.com Reviewed-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/inode.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 66969ae852b97..5195e083fc1e6 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -287,6 +287,13 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page) return false; }
+ if ((fi->i_flags & F2FS_CASEFOLD_FL) && !f2fs_sb_has_casefold(sbi)) { + set_sbi_flag(sbi, SBI_NEED_FSCK); + f2fs_warn(sbi, "%s: inode (ino=%lx) has casefold flag, but casefold feature is off", + __func__, inode->i_ino); + return false; + } + if (f2fs_has_extra_attr(inode) && f2fs_sb_has_compression(sbi) && fi->i_flags & F2FS_COMPR_FL && F2FS_FITS_IN_INODE(ri, fi->i_extra_isize,