diff options
| author | ZhengYuan Huang <gality369@gmail.com> | 2026-04-27 11:24:18 +0800 |
|---|---|---|
| committer | Konstantin Komarov <almaz.alexandrovich@paragon-software.com> | 2026-05-22 17:19:16 +0200 |
| commit | c26d8cc10468f825d82421a7e8a209984c9f101c (patch) | |
| tree | a57f77d1e0a31b5436ece53fab772d533002ea03 /fs | |
| parent | 7bf1052051af7065629df6ddc8be47b1ded99383 (diff) | |
| download | linux-next-history-c26d8cc10468f825d82421a7e8a209984c9f101c.tar.gz | |
fs/ntfs3: preserve non-DOS attribute bits in system.dos_attrib
[BUG]
A corrupted ntfs3 image can hit a NULL function pointer call in
generic_perform_write() after toggling system.ntfs_attrib and then
overwriting system.dos_attrib on the same file.
BUG: kernel NULL pointer dereference, address: 0000000000000000
\#PF: supervisor instruction fetch in kernel mode
\#PF: error_code(0x0010) - not-present page
PGD bed5067 P4D bed5067 PUD 0
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffff88801025f988 EFLAGS: 00010246
Call Trace:
generic_perform_write+0x409/0x8c0 mm/filemap.c:4255
__generic_file_write_iter+0x1bb/0x200 mm/filemap.c:4372
ntfs_file_write_iter+0xcd9/0x1c20 fs/ntfs3/file.c:1253
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x63b/0xf70 fs/read_write.c:686
ksys_write+0x133/0x250 fs/read_write.c:738
__do_sys_write fs/read_write.c:749 [inline]
__se_sys_write fs/read_write.c:746 [inline]
__x64_sys_write+0x77/0xc0 fs/read_write.c:746
...
[CAUSE]
system.ntfs_attrib updates ATTR_DATA flags via ni_new_attr_flags()
and switches i_mapping->a_ops to ntfs_aops_cmpr when
FILE_ATTRIBUTE_COMPRESSED is set. system.dos_attrib then overwrites
ni->std_fa from a one-byte DOS attribute value, clearing the compression
bit without updating ATTR_DATA or the mapping operations.
Old buffered writes use is_compressed(ni) to choose
__generic_file_write_iter(). That leaves generic_perform_write() calling
a NULL write_begin callback from ntfs_aops_cmpr.
[FIX]
Treat system.dos_attrib as a low-byte DOS attribute update and preserve the
existing non-DOS attribute bits in ni->std_fa. This keeps compressed and
sparse state consistent with ATTR_DATA and the mapping operations while
keeping the existing DOS attribute semantics intact.
Signed-off-by: ZhengYuan Huang <gality369@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ntfs3/xattr.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c index 9eeac0ab2b714..7e5118247660d 100644 --- a/fs/ntfs3/xattr.c +++ b/fs/ntfs3/xattr.c @@ -867,7 +867,9 @@ static noinline int ntfs_setxattr(const struct xattr_handler *handler, if (!strcmp(name, SYSTEM_DOS_ATTRIB)) { if (sizeof(u8) != size) goto out; - new_fa = cpu_to_le32(*(u8 *)value); + /* system.dos_attrib only covers the low DOS attribute byte. */ + new_fa = (ni->std_fa & ~cpu_to_le32(0xff)) | + cpu_to_le32(*(u8 *)value); goto set_new_fa; } |