File CVE-2016-8687.patch of Package libarchive.3431
commit e37b620fe8f14535d737e89a4dcabaed4517bf1a
Author: Tim Kientzle <kientzle@acm.org>
Date: Sun Aug 21 10:51:43 2016 -0700
Issue #767: Buffer overflow printing a filename
The safe_fprintf function attempts to ensure clean output for an
arbitrary sequence of bytes by doing a trial conversion of the
multibyte characters to wide characters -- if the resulting wide
character is printable then we pass through the corresponding bytes
unaltered, otherwise, we convert them to C-style ASCII escapes.
The stack trace in Issue #767 suggest that the 20-byte buffer
was getting overflowed trying to format a non-printable multibyte
character. This should only happen if there is a valid multibyte
character of more than 5 bytes that was unprintable. (Each byte
would get expanded to a four-charcter octal-style escape of the form
"\123" resulting in >20 characters for the >5 byte multibyte character.)
I've not been able to reproduce this, but have expanded the conversion
buffer to 128 bytes on the belief that no multibyte character set
has a single character of more than 32 bytes.
Index: libarchive-3.1.2/tar/util.c
===================================================================
--- libarchive-3.1.2.orig/tar/util.c
+++ libarchive-3.1.2/tar/util.c
@@ -181,7 +181,7 @@ safe_fprintf(FILE *f, const char *fmt, .
}
/* If our output buffer is full, dump it and keep going. */
- if (i > (sizeof(outbuff) - 20)) {
+ if (i > (sizeof(outbuff) - 128)) {
outbuff[i] = '\0';
fprintf(f, "%s", outbuff);
i = 0;