Fix file sync timing and prevent crash on missing SyncFromDiskMetadata #2595
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domenukk
reviewed
Oct 8, 2024
libafl/src/stages/sync.rs
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| last_time: new_max_time, | ||
| left_to_sync: new_files, | ||
| }; | ||
| match state.metadata_map_mut().get_mut::<SyncFromDiskMetadata>() { |
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You can use state.metadata_or_insert_with here, should be shorter
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Ah now we have one extra allocation :D |
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But actually, just set them to default values, you set them one step below anyway? |
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can you define "default values"? UNIX_EPOCH for max_time and empty vector for |
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just 0 and Vec::new() |
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We can even remove the parameters from |
I'd proceed like this then |
riesentoaster
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Dec 11, 2024
AFLplusplus#2595) * max_time is the current_time(); SyncFromDiskMetadata might not be in state * using metadata_or_insert_with
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I (think I) fixed the following two issues in the SyncFromDisk stage:
last_timeused to determine when to sync files was being updated by adding a fixed interval to the previous check time. This caused newly created files to be re-synced multiple times until the sync interval caught up with their timestamp. Let's say we start the fuzzer at 10:00:00 and begin debugging. After the first sync, thelast_timeis updated to 10:00:05. Now, after 8 minutes of debugging, it’s 10:08:00, and we’re still debugging. During this time, we created two files (A and B) in the sync directory at 10:03:00. At the next sync iteration, thelast_timeis still 10:00:05, so the fuzzer syncs the files A and B. However, because thelast_timeis behind the actual creation time of the files (10:03:00), A and B continue to be re-synced repeatedly until thelast_timecatches up to their timestamps.Solution: we better store the
current_time()aslast_timeand check the files creation time against the previouslast_time.SyncFromDiskMetadatawe were doing:state.metadata_mut::<SyncFromDiskMetadata>().unwrap(), which could cause a crash if the metadata was not present in state (first sync)