libgphoto2 is a camera access and control library. Versions up to and including 2.5.33 have an out-of-bounds read in the PTP_DPFF_Enumeration case of ptp_unpack_Sony_DPD() in camlibs/ptp2/ptp-pack.c (line 856). The function reads a 2-byte enumeration count N via dtoh16o(data, *poffset) without verifying that 2 bytes remain in the buffer. The standard ptp_unpack_DPD() at line 704 has this exact check, confirming the Sony variant omitted it by oversight. Commit 3b9f9696be76ae51dca983d9dd8ce586a2561845 fixes the issue.
Weakness
The product reads data past the end, or before the beginning, of the intended buffer.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libgphoto2 | Ubuntu | esm-infra/xenial | * |
Potential Mitigations
- Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.