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| author | Kent Overstreet <kent.overstreet@gmail.com> | 2021-06-24 20:19:25 +0300 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-10-23 00:09:07 +0300 |
| commit | fdc6b08451167bfc1ae260b252ad2bf2f9735f50 (patch) | |
| tree | 59a1d016ed2255d877644b257d64ba9a54268be5 /fs/bcachefs/bkey.c | |
| parent | 78d66ab1ca541ba95a9ad89780466398b348c230 (diff) | |
| download | linux-fdc6b08451167bfc1ae260b252ad2bf2f9735f50.tar.xz | |
bcachefs: Fix shift-by-64 in bch2_bkey_format_validate()
We need to ensure that packed formats can't represent fields larger than
the unpacked format, which is a bit tricky since the calculations can
also overflow a u64. This patch fixes a shift and simplifies the overall
calculations.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Diffstat (limited to 'fs/bcachefs/bkey.c')
| -rw-r--r-- | fs/bcachefs/bkey.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/bcachefs/bkey.c b/fs/bcachefs/bkey.c index 5de88a93f33f..3e62eeb6774e 100644 --- a/fs/bcachefs/bkey.c +++ b/fs/bcachefs/bkey.c @@ -623,22 +623,22 @@ const char *bch2_bkey_format_validate(struct bkey_format *f) if (f->nr_fields != BKEY_NR_FIELDS) return "incorrect number of fields"; + /* + * Verify that the packed format can't represent fields larger than the + * unpacked format: + */ for (i = 0; i < f->nr_fields; i++) { unsigned unpacked_bits = bch2_bkey_format_current.bits_per_field[i]; - u64 unpacked_mask = ~((~0ULL << 1) << (unpacked_bits - 1)); + u64 unpacked_max = ~((~0ULL << 1) << (unpacked_bits - 1)); + u64 packed_max = f->bits_per_field[i] + ? ~((~0ULL << 1) << (f->bits_per_field[i] - 1)) + : 0; u64 field_offset = le64_to_cpu(f->field_offset[i]); - if (f->bits_per_field[i] > unpacked_bits) + if (packed_max + field_offset < packed_max || + packed_max + field_offset > unpacked_max) return "field too large"; - if ((f->bits_per_field[i] == unpacked_bits) && field_offset) - return "offset + bits overflow"; - - if (((field_offset + ((1ULL << f->bits_per_field[i]) - 1)) & - unpacked_mask) < - field_offset) - return "offset + bits overflow"; - bits += f->bits_per_field[i]; } |