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Enabled erase=noop in test_rbyd, changed read* to error on leb128 overflow

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Now that reproducibility issues with erase_value=-1 (erase=noop) are
fixed, this much more useful to test than erase_value=0x1b. Especially
since erase=noop is filled with so many sharp corners.

These tests already found that we were being too confident with our
leb128/lleb128/tag parsing. Since we need to partially parse unfinished/
old commits, lfsr_dir_read* can easily encounter invalid leb128s during
normal operation. If this happens we should not assert.

Doing things correctly has a bit of a cost:

           code          stack
  before: 33928           2824
  after:  33976 (+0.1%)   2824 (+0.0%)

At least we haven't seen any issues with our valid bit invalidating
logic yet.
This commit is contained in:
Christopher Haster
2024-05-01 15:23:10 -05:00
parent 5fbf073bfb
commit ab2a1cb571
2 changed files with 14 additions and 6 deletions
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lfs.c
+13 -5
View File
@@ -1075,7 +1075,9 @@ static lfs_ssize_t lfsr_bd_readtag_(lfs_t *lfs,
return d_; return d_;
} }
// weights should be limited to 31-bits // weights should be limited to 31-bits
LFS_ASSERT(weight <= 0x7fffffff); if (weight > 0x7fffffff) {
return LFS_ERR_CORRUPT;
}
d += d_; d += d_;
lfs_size_t size; lfs_size_t size;
@@ -1084,7 +1086,9 @@ static lfs_ssize_t lfsr_bd_readtag_(lfs_t *lfs,
return d_; return d_;
} }
// sizes should be limited to 28-bits // sizes should be limited to 28-bits
LFS_ASSERT(size <= 0x0fffffff); if (size > 0x0fffffff) {
return LFS_ERR_CORRUPT;
}
d += d_; d += d_;
// optional checksum // optional checksum
@@ -1405,7 +1409,9 @@ static int lfsr_data_readleb128(lfs_t *lfs, lfsr_data_t *data,
return d; return d;
} }
// all leb128s in our system reserve the sign bit // all leb128s in our system reserve the sign bit
LFS_ASSERT(*word_ <= 0x7fffffff); if (*word_ > 0x7fffffff) {
return LFS_ERR_CORRUPT;
}
*data = lfsr_data_slice(*data, d, -1); *data = lfsr_data_slice(*data, d, -1);
return 0; return 0;
@@ -1422,9 +1428,11 @@ static inline int lfsr_data_readlleb128(lfs_t *lfs, lfsr_data_t *data,
if (err) { if (err) {
return err; return err;
} }
// little-leb128s should be limited to 28-bits // little-leb128s should be limited to 28-bits
LFS_ASSERT(*word_ <= 0x0fffffff); if (*word_ > 0x0fffffff) {
return LFS_ERR_CORRUPT;
}
return 0; return 0;
} }
tests/test_rbyd.toml
+1 -1
View File
@@ -2,7 +2,7 @@
after = 'test_bd' after = 'test_bd'
# test with a number of different erase values # test with a number of different erase values
defines.ERASE_VALUE = [0xff, 0x00, 0x1b] defines.ERASE_VALUE = [0xff, 0x00, -1]
# set block_size to the full size of disk so we can test arbitrarily # set block_size to the full size of disk so we can test arbitrarily
# large rbyd trees, we don't really care about block sizes at this # large rbyd trees, we don't really care about block sizes at this