Commit 679ce0ac authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds

random: fix output buffer folding

(As reported by linux@horizon.com)

Folding is done to minimize the theoretical possibility of systematic
weakness in the particular bits of the SHA1 hash output.  The result of
this bug is that 16 out of 80 bits are un-folded.  Without a major new
vulnerability being found in SHA1, this is harmless, but still worth
fixing.
Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
Cc: <linux@horizon.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 39a27902
...@@ -794,7 +794,7 @@ static void extract_buf(struct entropy_store *r, __u8 *out) ...@@ -794,7 +794,7 @@ static void extract_buf(struct entropy_store *r, __u8 *out)
buf[0] ^= buf[3]; buf[0] ^= buf[3];
buf[1] ^= buf[4]; buf[1] ^= buf[4];
buf[0] ^= rol32(buf[3], 16); buf[2] ^= rol32(buf[2], 16);
memcpy(out, buf, EXTRACT_SIZE); memcpy(out, buf, EXTRACT_SIZE);
memset(buf, 0, sizeof(buf)); memset(buf, 0, sizeof(buf));
} }
......
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