fix: free intervention strings on mcf NULL early return path#379
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eilandert wants to merge 1 commit into
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fix: free intervention strings on mcf NULL early return path#379eilandert wants to merge 1 commit into
eilandert wants to merge 1 commit into
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When msc_intervention() succeeds and fills intervention.log and/or intervention.url, then ngx_http_get_module_loc_conf() returns NULL (unexpected misconfiguration), the function returned immediately with NGX_HTTP_INTERNAL_SERVER_ERROR without freeing either string. Free both intervention.log and intervention.url before the early return to prevent the leak on this error path. Severity: Medium Reported-by: Security audit 2026-05-13
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Hi @eilandert, thanks for this PR too - here my question is the same: is it possible to add some tests? |
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Pull request overview
Fixes a memory leak in the Nginx ModSecurity connector by ensuring ModSecurity-provided intervention strings are freed when the request’s module loc-conf unexpectedly resolves to NULL.
Changes:
- Free
intervention.logandintervention.urlbefore returningNGX_HTTP_INTERNAL_SERVER_ERRORon themcf == NULLearly-return path.
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| if (intervention.log != NULL) { | ||
| free(intervention.log); | ||
| } | ||
| if (intervention.url != NULL) { | ||
| free(intervention.url); | ||
| } |
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When msc_intervention() succeeds and fills intervention.log and/or intervention.url, then ngx_http_get_module_loc_conf() returns NULL (unexpected misconfiguration), the function returned immediately with NGX_HTTP_INTERNAL_SERVER_ERROR without freeing either string.
Free both intervention.log and intervention.url before the early return to prevent the leak on this error path.