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| author | Hongling Zeng <zenghongling@kylinos.cn> | 2026-08-24 15:59:35 +0800 |
|---|---|---|
| committer | Namjae Jeon <linkinjeon@kernel.org> | 2026-08-27 21:50:45 +0900 |
| commit | acb1095fd2db884b417cb70808c886e4b615ff05 (patch) | |
| tree | 9ca92f044a45976e1b62e8074fecfee8a71f8561 | |
| parent | 6faa235a649e78a82e3230b849607f446ba65ed5 (diff) | |
| download | linux-acb1095fd2db884b417cb70808c886e4b615ff05.tar.gz linux-acb1095fd2db884b417cb70808c886e4b615ff05.zip | |
ntfs: fix memmove overlap in ntfs_new_attr_flags
When the record shrinks while the payload offsets increase (e.g., enabling
compression reduces padding, making arec_size < old_arec_size, but the header
grows by 8 bytes), moving the name first can overwrite the old mapping_pairs
before they are copied. Move mapping_pairs first in this case.
Since mp_ofs is derived from name_ofs, they always change in the same
direction. Checking name_ofs alone is sufficient.
Fixes: fc053f05ca28 ("ntfs: add reparse and ea operations")
Cc: stable@vger.kernel.org
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
| -rw-r--r-- | fs/ntfs/ea.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/fs/ntfs/ea.c b/fs/ntfs/ea.c index 9f0222c172d9..0bc29bf1f050 100644 --- a/fs/ntfs/ea.c +++ b/fs/ntfs/ea.c @@ -753,15 +753,36 @@ static int ntfs_new_attr_flags(struct ntfs_inode *ni, __le32 fattr) old_arec_size = le32_to_cpu(a->length); /* - * Move payloads before shrinking the record. Otherwise resizing moves + * Move payloads before shrinking the record. Otherwise resizing moves * the following attribute over the old payload before it can be copied. + * + * When offsets increase, move mapping_pairs first to avoid name + * overwriting the start of mapping_pairs. */ if (arec_size < old_arec_size) { - if (a->name_length && name_ofs != old_name_ofs) - memmove((u8 *)a + name_ofs, (u8 *)a + old_name_ofs, - a->name_length * sizeof(__le16)); - if (mp_ofs != old_mp_ofs) - memmove((u8 *)a + mp_ofs, (u8 *)a + old_mp_ofs, mp_size); + if (name_ofs > old_name_ofs) { + /* Payload offsets increased: move mapping pairs first. */ + if (mp_ofs != old_mp_ofs) + memmove((u8 *)a + mp_ofs, + (u8 *)a + old_mp_ofs, + mp_size); + if (a->name_length && name_ofs != old_name_ofs) + memmove((u8 *)a + name_ofs, + (u8 *)a + old_name_ofs, + a->name_length * + sizeof(__le16)); + } else { + /* Payload offsets decreased or unchanged: move name first. */ + if (a->name_length && name_ofs != old_name_ofs) + memmove((u8 *)a + name_ofs, + (u8 *)a + old_name_ofs, + a->name_length * + sizeof(__le16)); + if (mp_ofs != old_mp_ofs) + memmove((u8 *)a + mp_ofs, + (u8 *)a + old_mp_ofs, + mp_size); + } } err = ntfs_attr_record_resize(ctx->mrec, a, arec_size); |