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Diffstat (limited to 'CHANGES')
| -rw-r--r-- | CHANGES | 27 |
1 files changed, 26 insertions, 1 deletions
@@ -2,7 +2,32 @@ OpenSSL CHANGES _______________ - Changes between 0.9.6a and 0.9.6b [XX xxx XXXX] + Changes between 0.9.6a and 0.9.6b [9 Jul 2001] + + *) Change ssleay_rand_bytes (crypto/rand/md_rand.c) + to avoid a SSLeay/OpenSSL PRNG weakness pointed out by + Markku-Juhani O. Saarinen <markku-juhani.saarinen@nokia.com>: + PRNG state recovery was possible based on the output of + one PRNG request appropriately sized to gain knowledge on + 'md' followed by enough consecutive 1-byte PRNG requests + to traverse all of 'state'. + + 1. When updating 'md_local' (the current thread's copy of 'md') + during PRNG output generation, hash all of the previous + 'md_local' value, not just the half used for PRNG output. + + 2. Make the number of bytes from 'state' included into the hash + independent from the number of PRNG bytes requested. + + The first measure alone would be sufficient to avoid + Markku-Juhani's attack. (Actually it had never occurred + to me that the half of 'md_local' used for chaining was the + half from which PRNG output bytes were taken -- I had always + assumed that the secret half would be used.) The second + measure makes sure that additional data from 'state' is never + mixed into 'md_local' in small portions; this heuristically + further strengthens the PRNG. + [Bodo Moeller] *) Fix crypto/bn/asm/mips3.s. [Andy Polyakov] |