I don't know how it is possible for /dev/hwrng to be present but unreadable. Loading rng-core on a system without a hardware random driver doesn't do it. However, it is possible to reproduce this poor randomisation after running 'ln -s null /dev/hwrng'.
I've uploaded a fix for this and am attaching the NMU diff.
Ben.
--
Ben Hutchings
Lowery's Law:
If it jams, force it. If it breaks, it needed replacing anyway.
diff -Nru macchanger-1.7.0/debian/changelog macchanger-1.7.0/debian/changelog --- macchanger-1.7.0/debian/changelog 2014-12-18 11:51:19.000000000 +0000 +++ macchanger-1.7.0/debian/changelog 2015-01-16 23:22:14.000000000 +0000 @@ -1,3 +1,10 @@ +macchanger (1.7.0-5.1) unstable; urgency=medium + + * Non-maintainer upload + * Check for random device read errors (Closes: #775005) + + -- Ben Hutchings <b...@decadent.org.uk> Fri, 16 Jan 2015 23:22:13 +0000 + macchanger (1.7.0-5) unstable; urgency=low * fix maintainer-script-without-set-e config diff -Nru macchanger-1.7.0/debian/patches/check-random-device-read-errors.patch macchanger-1.7.0/debian/patches/check-random-device-read-errors.patch --- macchanger-1.7.0/debian/patches/check-random-device-read-errors.patch 1970-01-01 01:00:00.000000000 +0100 +++ macchanger-1.7.0/debian/patches/check-random-device-read-errors.patch 2015-01-16 23:03:34.000000000 +0000 @@ -0,0 +1,47 @@ +Description: Check for random device read errors + In some cases it is possible to open /dev/hwrng but not to read from it. + We need to check for errors and move on to the next possible random device + in this case. +Author: Ben Hutchings <b...@decadent.org.uk> +Bug-Debian: https://bugs.debian.org/775005 + +--- +--- a/src/main.c ++++ b/src/main.c +@@ -91,17 +91,29 @@ print_mac (const char *s, const mac_t *m + static void + random_seed (void) + { ++ static const char *const dev_names[] = { ++ "/dev/hwrng", ++ "/dev/random", ++ "/dev/urandom", ++ NULL, ++ }; + int fd; + struct timeval tv; + unsigned int seed; ++ const char *const *name; ++ ssize_t read_len = 0; + +- if ((fd = open("/dev/hwrng", O_RDONLY)) >= 0 || +- (fd = open("/dev/random", O_RDONLY)) >= 0 || +- (fd = open("/dev/urandom", O_RDONLY)) >= 0) +- { +- read (fd, &seed, sizeof(seed)); +- close (fd); +- } else { ++ for (name = dev_names; *name; name++) { ++ fd = open(*name, O_RDONLY); ++ if (fd >= 0) { ++ read_len = read (fd, &seed, sizeof(seed)); ++ close (fd); ++ if (read_len == sizeof(seed)) ++ break; ++ } ++ } ++ ++ if (read_len != sizeof(seed)) { + gettimeofday (&tv, NULL); + seed = (getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec; + } diff -Nru macchanger-1.7.0/debian/patches/series macchanger-1.7.0/debian/patches/series --- macchanger-1.7.0/debian/patches/series 2014-03-18 14:59:20.000000000 +0000 +++ macchanger-1.7.0/debian/patches/series 2015-01-16 22:51:05.000000000 +0000 @@ -1,3 +1,4 @@ 02-fix_usage_message.patch 06-update_OUI_list.patch 08-fix_random_MAC_choice.patch +check-random-device-read-errors.patch
signature.asc
Description: This is a digitally signed message part
