rxi/microtar

A stack-based buffer overflow exists in the raw_to_header() function in src/microtar.c in rxi microtar 0.1.0. The function copies the 100-byte name and linkname fields of a TAR header with strcpy() without guaranteeing null termination of the source. The POSIX ustar format permits these fixed-width fields to be fully populated with non-null bytes, so a crafted archive whose linkname field (followed by the trailing padding of the 512-byte raw header) contains no null terminator causes strcpy() to read past the end of the 512-byte raw header stack buffer and to write past the destination header buffer. A remote attacker who supplies a crafted TAR archive that the victim opens or parses (via mtar_open(), mtar_read_header(), or mtar_find()) can cause an out-of-bounds read and a stack buffer overflow, resulting in denial of service (crash) and potentially arbitrary code execution. Confirmed with AddressSanitizer: stack-buffer-overflow READ of size 356 in raw_to_header at src/microtar.c:112.

An integer overflow in the mtar_next() function in src/microtar.c in rxi microtar 0.1.0 allows a remote attacker to cause a denial of service (uncontrolled CPU consumption / infinite loop) via a crafted tar archive. mtar_next() computes the offset to the next record as round_up(h.size, 512) + sizeof(mtar_raw_header_t) using 32-bit arithmetic. When the header size field is a multiple of 512 in the range 0xFFFFFC01-0xFFFFFE00 (e.g. 0xFFFFFE00), the addition wraps to 0, so mtar_next() seeks to the current record position instead of advancing. As a result, mtar_find() and any loop that iterates entries with mtar_next() repeat indefinitely over the same record, hanging the process at 100% CPU with no recovery.

microtar through 0.1.0 contains a stack-based buffer overflow vulnerability in the raw_to_header() function in src/microtar.c that allows attackers to corrupt adjacent stack memory by supplying a crafted TAR archive with non-null-terminated name or linkname fields. The function uses strcpy() to copy 100-byte ustar format fields that lack null terminators, causing writes of up to 355 bytes into a 100-byte destination buffer when mtar_open(), mtar_find(), or mtar_read_header() process attacker-supplied TAR archives.