Fix buffer overflow in wc_HpkeLabeledExtract via oversized ECH#9927
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anhu wants to merge 1 commit intowolfSSL:masterfrom
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Fix buffer overflow in wc_HpkeLabeledExtract via oversized ECH#9927anhu wants to merge 1 commit intowolfSSL:masterfrom
anhu wants to merge 1 commit intowolfSSL:masterfrom
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…config SetEchConfigsEx accepted arbitrarily large ECH configs without bounds checking rawLen. This allowed attacker-controlled data (from DNS HTTPS records or TLS retry_configs) to overflow the fixed 512-byte labeled_ikm stack buffer in wc_HpkeLabeledExtract during ClientHello construction. Add MAX_ECH_CONFIG_RAW_SZ to reject oversized configs at parse time, and add bounds checks in both wc_HpkeLabeledExtract and wc_HpkeLabeledExpand before writing into their fixed-size buffers. Fixes ZD#21309
philljj
reviewed
Mar 9, 2026
| * is concatenated into a MAX_HPKE_LABEL_SZ buffer in wc_HpkeLabeledExtract | ||
| * along with version (7) + suite_id (HPKE_SUITE_ID_LEN) + label (~12) + | ||
| * TLS info prefix (8) overhead. */ | ||
| #define MAX_ECH_CONFIG_RAW_SZ (MAX_HPKE_LABEL_SZ - 50) |
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Where does the - 50 come from?
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Closing because #9737 fixes this issue. |
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SetEchConfigsEx accepted arbitrarily large ECH configs without bounds checking rawLen. This allowed attacker-controlled data (from DNS HTTPS records or TLS retry_configs) to overflow the fixed 512-byte labeled_ikm stack buffer in wc_HpkeLabeledExtract during ClientHello construction.
Add MAX_ECH_CONFIG_RAW_SZ to reject oversized configs at parse time, and add bounds checks in both wc_HpkeLabeledExtract and wc_HpkeLabeledExpand before writing into their fixed-size buffers.
Fixes ZD#21309