From: "Steven M. Schweda" Subject: Fix CVE-2016-9844, buffer overflow in zipinfo Bug-Debian: https://bugs.debian.org/847486 Bug-Ubuntu: https://launchpad.net/bugs/1643750 X-Debian-version: 6.0-21 Upstream-Status: Backport CVE: CVE-2016-9844 Signed-off-by: Zhixiong Chi --- a/zipinfo.c +++ b/zipinfo.c @@ -1921,7 +1921,18 @@ ush dnum=(ush)((G.crec.general_purpose_bit_flag>>1) & 3); methbuf[3] = dtype[dnum]; } else if (methnum >= NUM_METHODS) { /* unknown */ - sprintf(&methbuf[1], "%03u", G.crec.compression_method); + /* 2016-12-05 SMS. + * https://launchpad.net/bugs/1643750 + * Unexpectedly large compression methods overflow + * &methbuf[]. Use the old, three-digit decimal format + * for values which fit. Otherwise, sacrifice the "u", + * and use four-digit hexadecimal. + */ + if (G.crec.compression_method <= 999) { + sprintf( &methbuf[ 1], "%03u", G.crec.compression_method); + } else { + sprintf( &methbuf[ 0], "%04X", G.crec.compression_method); + } } for (k = 0; k < 15; ++k)