GHSA-7cfq-5mhv-jrp9: Inspektor Gadget: Unprivileged container can crash USDT note parser via crafted ELF (no shipped gadget affected)
SummaryA malicious container can crash or destabilize the privileged Inspektor Gadget process when a **gadget using USDT probes** is deployed. The vulnerability is in the USDT note parser (`pkg/uprobetracer/usdt.go`) which is invoked when a gadget with a `SEC("usdt/...")` section attaches to a target binary. An unprivileged process can place a crafted ELF binary at the expected library path, triggering one of two attack vectors:**Panic (immediate crash):** A stapsdt note with a small `DescSize` causes an out-of-bounds slice access, panicking the IG process.**Memory exhaustion (OOM kill):** A stapsdt note with a very large `NameSize` or `DescSize` causes IG to allocate up to ~4 GiB of memory, which can killnthe process if deployed with memory restrictions (e.g., cgroup limits).**Important:** The vulnerability is only triggered when running a gadget that uses USDT probes (i.e., contains a `SEC("usdt/...")` eBPF section). No gadget shipped by the Inspektor Gadget project uses USDT today. Users who deploy their own custom USDT gadgets are affected.Severity**Low** — Denial of Service (process crash or OOM) of a privileged host process, triggered by an unprivileged container. The vulnerable code path is only reached when a gadget using USDT probes is deployed. No such gadget is shipped by the Inspektor Gadget project; only users running custom USDT gadgets are affected.**Attack vector**: An unprivileged process in a container places a crafted ELF  file at a path that a USDT gadget targets (e.g., a library name resolved via the container's ld cache). When the gadget attaches, IG parses the malicious ELF and crashes.**Impact**: The IG process panics and crashes (vector 1) or is OOM-killed (vector 2). This is a DoS against the monitoring infrastructure, not a code execution or privilege escalation vulnerability.**Affected component**: `pkg/uprobetracer/usdt.go`, function `getUsdtInfo()`**Prerequisites**: A gadget with a `SEC("usdt/...")` eBPF section must be running and configured to attach to a library inside the attacker's container.
**No shipped gadgets use USDT probes**, so this only affects deployments with custom USDT gadgets.Affected VersionsAll versions of Inspektor Gadget that include USDT support in `pkg/uprobetracer/usdt.go`, starting from v0.28.0 (commit 7ee5e7a90 "pkg/uprobetracer: support USDT trace points").Root CauseVector 1: Out-of-bounds slice access (panic)In `pkg/uprobetracer/usdt.go`, the function `getUsdtInfo()` parses stapsdt notes from an ELF file's `.note.stapsdt` section. When a matching note is found (`name == "stapsdt\0"` and `type == 3`), it reads three address fields from the note descriptor:For a 64-bit ELF, `wordSize = 8`, so this requires `desc` to be at least 24 bytes. However, `desc` is allocated based on the note's `DescSize` field from the ELF file:A crafted ELF with `DescSize = 1` produces a 4-byte `desc` buffer. The expression `desc[:8]` then panics with:Vector 2: Unbounded memory allocation (OOM)The `NameSize` and `DescSize` fields from the note header are used directly to allocate memory without any upper bound:A crafted ELF with `NameSize = 0xFFFFFFFF` would attempt to allocate ~4 GiB of memory. Under cgroup memory limits (common in Kubernetes deployments), this triggers an OOM kill of the IG process.Vector 3: Missing panic recovery for `debug/elf`Go's `debug/elf` package is [not hardened against adversarial inputs](https://github.com/golang/go/issuesq=is%3Aissue+is%3Aopen+debug%2Felf+in%3Atitle) and may panic on malformed ELF headers. The cilium/ebpf library addresses this with its [`SafeELFFile` wrapper](https://github.com/cilium/ebpf/blob/main/internal/safeelf.go) that uses `recover()`, but `getUsdtInfo()` calls `elf.NewFile()` directly without any panic recovery.FixThe fix (3 changes in `pkg/uprobetracer/usdt.go`):**Bounds check on descriptor size**: Validate `len(desc) >= 3*wordSize` before accessing the address fields. Reject malformed notes with an error instead of panicking.**Cap allocation sizes**: Limit `NameSize` and `DescSize` to a reasonable maximum (1 MiB) before allocating memory, preventing DoS via memory exhaustion. There is no standard upper bound for ELF note fields; 1 MiB is a generous arbitrary cap — legitimate USDT notes are typically under 1 KB.**Panic recovery**: Wrap `getUsdtInfo()` with `defer/recover` to catch any panics from `debug/elf` on malformed input, converting them to errors.RelatedGo `debug/elf` known issues: https://github.com/golang/go/issues?q=is%3Aissue+is%3Aopen+debug%2Felf+in%3Atitlecilium/ebpf `SafeELFFile` wrapper: https://github.com/cilium/ebpf/blob/main/internal/safeelf.go — uses `recover()` around all `debug/elf` operations for exactly this reason.
CVSS v4.0: 2.9