bgp: fix stack buffer overflow in EVPN parseNlriData#34
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FengPan-Frank merged 1 commit intoApr 25, 2026
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Add destination-size clamp before memcpy into ip_binary[16] in three EVPN route-type parsing paths (type-2 MAC-IP, type-3 IMET, type-4 ES). Wire-supplied ip_len field (1 byte) could produce addr_bytes up to 31, overflowing the 16-byte stack buffer. Fix: clamp addr_bytes to sizeof(ip_binary) before memcpy. Signed-off-by: xq9mend <xq9mend@users.noreply.github.com>
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/azp run |
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Azure Pipelines successfully started running 1 pipeline(s). |
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Hi @xq9mend is it fixed in openbmp as well? pls add a link if so. Thanks |
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Submitted a fix to upstream: SNAS/openbmp#100 |
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Why I did it
ip_binary is a 16-byte stack buffer in EVPN::parseNlriData. The IP Address Length field read from wire data (1 byte) was divided by 8 to get addr_bytes, which can be up to 31. This value was passed directly to memcpy with no destination-size check, allowing up to 15 bytes of stack overflow. Three parsing paths were affected: type-2 (MAC-IP Advertisement), type-3 (IMET), and type-4 (ES).
How I did it
Added a clamp after the addr_bytes computation in all three paths:
Also fixed the type-4 path to use the clamped addr_bytes in memcpy instead of the raw unclamped expression it previously used.
How to verify it
Build passes: cmake + make with no errors (tested on Ubuntu 24.04, gcc 13). No unit tests exist in this repo.
The same fix has been submitted upstream: SNAS/openbmp#100