Description
How frequently does the bug occur?
Always
Description
We're encountering a crash in Realm Core with the following message:
Assertion failed: has_refs() and this terminating due to uncaught exception of type realm::util::DecryptionFailed: Decryption failed: page 98 in file of size 3198976 failed the HMAC check. Either the encryption key is incorrect or data is corrupted
This occurs when two processes simultaneously access the same encrypted Realm file - one writing, the other reading. Based on our investigation, this seems to be a race condition that happens during concurrent encrypted access across processes.
Reproduction
We've created a minimal example with two apps that reproduce the issue:
- TestApp1 (the listener): opens the encrypted Realm and continuously reads from it.
- TestApp2 (the writer): opens the same Realm file and performs repeated writes.
Steps to Reproduce:
-
Clone this: https://github.com/c128128/RealmBug
-
Start TestApp1 (the listener).
-
Then launch TestApp2 (the writer).
-
Within a few moments, TestApp1 crashes with:
Assertion failed: m_has_refs with (m_ref, ndx, m_size) = [5232, 0, 0]
or sometimes with:
terminating due to uncaught exception of type realm::util::DecryptionFailed: Decryption failed: page 98 in file of size 3198976 failed the HMAC check. Either the encryption key is incorrect or data is corrupted
Environment
- RealmSwift version: 10.54.5
- RealmCore version: 14.14.0
- Platform: Mac Catalyst
- Encryption: Enabled (64-byte key)
- Concurrency: Two processes accessing the same Realm file simultaneously
Key Observations
- The crash does not occur with an unencrypted Realm.
- The crash seems to occur during memory mapping or decryption, possibly due to unsynchronized access to shared encrypted pages.
- Appears to be an issue within Realm Core's internal caching or reference tracking.
- The bug was introduced after
realm-swift10.51.0 - everything works fine on 10.51.0, but crashes consistently starting with 10.52.0 and later versions.
Can you reproduce the bug?
Always
Version
10.54.5
What Atlas Services are you using?
Local Database only
Are you using encryption?
Yes
Platform OS and version(s)
macOS 15.5 (Apple M1 Max)
related #8081