Package: apg Version: 2.2.3-3 Severity: important Tags: patch A couple of invocations of apg with certain parameters (apg -M SNCL -m 10 -x 10 -a 1 for example) totally drain /dev/random (from an strace log):
open("/dev/random", O_RDONLY) = 3
[...]
read(3, "[\354x\341\375\25\306\337O\322v\243{$m\371WQ\266\210\34"..., 4096) =
128
close(3) = 0
As you can see, apg requests 4096 bytes from /dev/random
which is totally excessive since it only uses 8 of them.
Now, the code actually requests 8, so the problem is
likely in the C library. Attached is a patch to use regular
functions open/read/close instead of the C library
ones and really read only 8 bytes.
-- System Information:
Debian Release: testing/unstable
APT prefers unstable
APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: powerpc (ppc)
Shell: /bin/sh linked to /bin/bash
Kernel: Linux 2.6.13-rc3
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Versions of packages apg depends on:
ii libc6 2.3.5-1 GNU C Library: Shared libraries an
apg recommends no packages.
-- no debconf information
--- apg-2.2.3.orig/rnd.c
+++ apg-2.2.3/rnd.c
@@ -36,6 +36,7 @@
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
+#include <fcntl.h>
#include "rnd.h"
#ifndef APG_USE_SHA
@@ -176,25 +177,31 @@
void
x917_setseed (UINT32 seed, int quiet)
{
- FILE * dr;
+ int fd;
UINT32 drs[2];
UINT32 pid = 0;
pid = (UINT32)getpid();
+
+ /* NOTE: this function intentionally does not use
+ * the regular <stdio> API because fread may
+ * read much more data than requested (up to
+ * 4K), which is extremely bad with /dev/random
+ */
- if ( (dr = fopen(APG_DEVRANDOM, "r")) != NULL)
+ if ( (fd = open(APG_DEVRANDOM, O_RDONLY)) != -1)
{
- (void)fread( (void *)&drs[0], 8, 1, dr);
+ read(fd, (void *)&drs[0], 8);
__rnd_seed[0] = seed ^ drs[0];
__rnd_seed[1] = seed ^ drs[1];
- (void) fclose(dr);
+ close(fd);
}
- else if ( (dr = fopen(APG_DEVURANDOM, "r")) != NULL)
+ else if ( (fd = open(APG_DEVURANDOM, O_RDONLY)) != -1)
{
- (void)fread( (void *)&drs[0], 8, 1, dr);
+ read(fd, &drs[0], 8);
__rnd_seed[0] = seed ^ drs[0];
__rnd_seed[1] = seed ^ drs[1];
- (void) fclose(dr);
+ close(fd);
}
else
{
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