Backport:v0.8 Handle multiple URL and DNS selectors correctly #726
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Currently we have experimental support for URL and DNS actions, which could be used to trigger Thinkst canaries. This experimental support incorrectly handles multiple selectors – it simply collects all the URLs in the kprobe and all the FQDNs in the kprobe into lists, and when a URL or FQDN action fires on it, it triggers everything in the corresponding list. This is obviously wrong. This commit fixes this as follows. Each kprobe stores a table of URLs and FQDNs that it references, each entry with its own index. These indices are provided in the config to the match actions in the selectors, and the BPF program reports the matching index. In user space, the URL or FQDN is retrieved from the table using this index. Note that only one URL and/or FQDN action is permitted per selector. It will be possible to enable multiple if necessary, but it is deemed that a single trigger should be sufficient to trigger any further triggers. Signed-off-by: Kevin Sheldrake <[email protected]>
kevsecurity
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tixxdz
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Feb 23, 2023
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Currently we have experimental support for URL and DNS actions, which could be used to trigger Thinkst canaries. This experimental support incorrectly handles multiple selectors – it simply collects all the URLs in the kprobe and all the FQDNs in the kprobe into lists, and when a URL or FQDN action fires on it, it triggers everything in the corresponding list. This is obviously wrong.
This commit fixes this as follows. Each kprobe stores a table of URLs and FQDNs that it references, each entry with its own index. These indices are provided in the config to the match actions in the selectors, and the BPF program reports the matching index. In user space, the URL or FQDN is retrieved from the table using this index.
Note that only one URL and/or FQDN action is permitted per selector. It will be possible to enable multiple if necessary, but it is deemed that a single trigger should be sufficient to trigger any further triggers.
[Upstream commit: 15d2eaa]