Brian Masney

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** The issue is related to the crypto component of the Linux kernel, specifically the qcom-rng module. The generate function in struct rng alg expects the destination buffer to be completely filled if the function returns 0. However, qcom rng read() can run into a situation where the buffer is partially filled with randomness and the remaining part of the buffer is zeroed since qcom rng generate() doesn't check the return value. This can be reproduced by running the command `kcapi-rng -b 9000000 > OUTFILE` from libkcapi, resulting in a file with three huge sections containing all zeros. The issue is caused by the code where the test `val & PRNG STATUS DATA AVAIL` fails. To fix this, qcom rng read() should always return with a full buffer if the function returns success, and qcom rng generate() should return the correct value. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.