ext/ftp: avoid one-byte out-of-bounds write in ftp_readline()#102
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iliaal wants to merge 1 commit into
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ext/ftp: avoid one-byte out-of-bounds write in ftp_readline()#102iliaal wants to merge 1 commit into
iliaal wants to merge 1 commit into
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The bug80901 fix (09696ee) terminates an over-long response with *data = 0, but when the line fills the whole FTP_BUFSIZE inbuf without a CR/LF, data points at inbuf[FTP_BUFSIZE] and the terminator is written one byte past the buffer, into the adjacent ftpbuf_t::extra field. Reserve the final byte for the terminator so it always lands inside inbuf. A buffer-filling response loses its last character (bug80901's SYST reply is now 4095 visible chars, with the terminator taking the 4096th slot).
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Submitted upstream as php#22377. |
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The bug80901 fix (09696ee) terminates an over-long server response with
*data = 0, but when the line fills the whole FTP_BUFSIZE inbuf without a CR/LF,datapoints atinbuf[FTP_BUFSIZE]and the terminator is written one byte past the buffer, into the adjacentftpbuf_t::extrafield. Reserving the final byte keeps the terminator inside inbuf. The overwrite is intra-struct (same allocation) so neither valgrind nor ASAN flags it. The existing bug80901 test exercises this exact path (a 4096-byte SYST reply); its expected output drops from 4096 to 4095 visible chars because the terminator now legitimately occupies the last slot instead of overflowing.