[f2fs-dev] [PATCH] f2fs: reject CASEFOLD inode flag without casefold feature

[f2fs-dev] [PATCH] f2fs: reject CASEFOLD inode flag without casefold feature

[Eric Biggers]

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>
---
 fs/f2fs/inode.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 2ed935c13aed..d5664bc7d6c6 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,

base-commit: db40330b0de9a9d9939178f48cd5fc5e3fab14de
-- 
2.28.0.1011.ga647a8990f-goog



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Re: [f2fs-dev] [PATCH] f2fs: reject CASEFOLD inode flag without casefold feature

[Gabriel Krisman Bertazi]

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


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Re: [f2fs-dev] [PATCH] f2fs: reject CASEFOLD inode flag without casefold feature

[Chao Yu]

On 2020/10/9 3:15, Eric Biggers wrote:
> 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>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,


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Re: [f2fs-dev] general protection fault in utf8_casefold

[syzbot]

syzbot has bisected this issue to:

commit 91db9311945f01901ddb9813ce11364de214a156
Author: Su Sung Chung <Su.Chung@amd.com>
Date:   Mon Jul 8 15:31:39 2019 +0000

    drm/amd/display: refactor gpio to allocate hw_container in constructor

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1012ee8b900000
start commit:   c85fb28b Merge tag 'arm64-fixes' of git://git.kernel.org/p..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1212ee8b900000
console output: https://syzkaller.appspot.com/x/log.txt?x=1412ee8b900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=de7f697da23057c7
dashboard link: https://syzkaller.appspot.com/bug?extid=05139c4039d0679e19ff
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12316e00500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16e80420500000

Reported-by: syzbot+05139c4039d0679e19ff@syzkaller.appspotmail.com
Fixes: 91db9311945f ("drm/amd/display: refactor gpio to allocate hw_container in constructor")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection


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