mod_proxy_http2: reserve NUL when rewriting a backend Link header uri - #711
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arshsmith1 wants to merge 1 commit into
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mod_proxy_http2: reserve NUL when rewriting a backend Link header uri#711arshsmith1 wants to merge 1 commit into
arshsmith1 wants to merge 1 commit into
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map_link() in h2_proxy_util.c rewrites the URI of a backend Link response header into a fixed HUGE_STRING_LEN stack buffer. In the branch that swaps the real backend uri for the proxy uri, need_len is computed as psu_len + link_len without the +1 the sibling branch a few lines above uses to reserve the terminating NUL, so the oversize guard admits need_len == sizeof(buffer) and the following buffer[buffer_len] = '\0' writes one byte past the array. A reverse proxy over HTTP/2 with ProxyPreserveHost off reaches this when a backend returns a Link header whose absolute URI is sized so psu_len + (link_len - rbu_len) equals 8192. Adding the +1 makes the check reserve room for the NUL, matching the other branch.