patches/packages/libXcursor-1.1.15-i486-1_slack13.0.txz
Fix heap overflows when parsing malicious files. (CVE-2017-16612)
It is possible to trigger heap overflows due to an integer overflow
while parsing images and a signedness issue while parsing comments.
The integer overflow occurs because the chosen limit 0x10000 for
dimensions is too large for 32 bit systems, because each pixel takes
4 bytes. Properly chosen values allow an overflow which in turn will
lead to less allocated memory than needed for subsequent reads.
The signedness bug is triggered by reading the length of a comment
as unsigned int, but casting it to int when calling the function
XcursorCommentCreate. Turning length into a negative value allows the
check against XCURSOR_COMMENT_MAX_LEN to pass, and the following
addition of sizeof (XcursorComment) + 1 makes it possible to allocate
less memory than needed for subsequent reads.
For more information, see:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-16612
(* Security fix *)