upipe-ts: fix use-after-free parsing PMT CA descriptors#1172
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uref_ts_flow_get_descriptor() returns a pointer directly into flow_def's udict inline buffer. The uref_ts_flow_set_capid()/set_sysid() calls (and the cat_onid/cat_esid sets inside upipe_ts_catd_parse_bissca_descs) add attributes to that same uref, which can realloc the udict buffer and invalidate the descriptor pointer. Subsequent reads through it (desc09_get_sysid, the loop advance, and the BISS-CA parse) were use-after-free, as caught by AddressSanitizer at desc09_get_sysid(). Parse a stack copy of the descriptor list instead, so the descriptor reads are independent of any reallocation of flow_def. This mirrors the existing VLA copy pattern in upipe_ts_pmtd_parse_descs(); len is bounded by the PMT program_info_length. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Claude verified the VLA can't get > 4096 bytes. |
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Fixes #1171 |
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uref_ts_flow_get_descriptor() returns a pointer directly into flow_def's udict inline buffer. The uref_ts_flow_set_capid()/set_sysid() calls (and the cat_onid/cat_esid sets inside upipe_ts_catd_parse_bissca_descs) add attributes to that same uref, which can realloc the udict buffer and invalidate the descriptor pointer. Subsequent reads through it (desc09_get_sysid, the loop advance, and the BISS-CA parse) were use-after-free, as caught by AddressSanitizer at desc09_get_sysid().
Parse a stack copy of the descriptor list instead, so the descriptor reads are independent of any reallocation of flow_def. This mirrors the existing VLA copy pattern in upipe_ts_pmtd_parse_descs(); len is bounded by the PMT program_info_length.