sspi: free libcurl allocated memory with curlx_free#21990
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DecryptMessage() decrypts the buffer in place, overwriting the original contents. It does not allocate any new buffer so the single original buffer should be freed using the same memory "system" that allocated it. Reported-by: Trail of Bits
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Pull request overview
This PR adjusts SSPI/Kerberos handling to avoid freeing buffers with FreeContextBuffer() when the decrypted data is written in-place into an existing libcurl-allocated buffer (per DecryptMessage() behavior).
Changes:
- Clarify via comments that
DecryptMessage()decrypts in place and does not allocate a new buffer. - Remove
FreeContextBuffer()calls for decrypted buffers that are not SSPI-allocated. - Switch to freeing the original libcurl-allocated buffer (
curlx_free) in the SOCKS SSPI path.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| lib/vauth/krb5_sspi.c | Removes an incorrect FreeContextBuffer() and documents in-place decryption behavior. |
| lib/socks_sspi.c | Removes FreeContextBuffer() usage for decrypted data and updates cleanup to free the libcurl-allocated buffer. |
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jay
requested changes
Jun 12, 2026
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DecryptMessage() decrypts the buffer in place, overwriting the original contents. It does not allocate any new buffer so the single original buffer should be freed using the same memory "system" that allocated it.
Reported-by: Trail of Bits