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Message-ID: <20130202222233.GN6181@port70.net> Date: Sat, 2 Feb 2013 23:22:33 +0100 From: Szabolcs Nagy <nsz@...t70.net> To: musl@...ts.openwall.com Subject: Re: [PATCH] Add support for mkostemp, mkstemps and mkostemps * Anthony G. Basile <basile@...nsource.dyc.edu> [2013-02-02 15:38:43 -0500]: > 2. This is from uclibc. Clearly, static is critical here, but still > they never initialize a value of 'value' on first entry into the > function, so that memory is dirty to start. Mine is worse, but I > wonder if this is still a bug there. > > static void brain_damaged_fillrand(unsigned char *buf, unsigned int len) > { > ... > static uint64_t value; > gettimeofday(&tv, NULL); > value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid(); > ... static variables are always initialized to 0 they use static so every call to that function uses some entropy from the previous call (in multithreaded code it may not work that way) > 3. I retested your address approach. I like it but it only maps to > upper and lower case letters, no numbers which uclibc and glibc do. yes i used 6*5 bit for the names, which makes sense: r is 32bits usually (ie. that code can generate 2^30 different names) uclibc/glibc can generate 62^6 names (about 2^36) which is a bit more but by not much > clock_gettime(CLOCK_REALTIME, &ts); > r = ts.tv_nsec*65537 ^ (uintptr_t)&ts / 16 + (uintptr_t)template; > for (i=0; i<6; i++, r>>=5) > template[i] = 'A'+(r&15)+(r&16)*2; >
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