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author | Robert de Bath <rdebath@poboxes.com> | 1998-02-01 11:26:21 +0100 |
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committer | Lubomir Rintel <lkundrak@v3.sk> | 2013-10-23 23:40:14 +0200 |
commit | 48f0b3eb836162d41622cedc1eb5f5168168fb8e (patch) | |
tree | c53156383d4682a0a296f6611575dbc1d64d1881 /libc/misc/crypt.c | |
parent | 48798bf2eb93ec3b99720ac2e16093441156653d (diff) | |
download | dev86-48f0b3eb836162d41622cedc1eb5f5168168fb8e.tar.gz |
Import Dev86src-0.13.5.tar.gzv0.13.5
Diffstat (limited to 'libc/misc/crypt.c')
-rw-r--r-- | libc/misc/crypt.c | 45 |
1 files changed, 34 insertions, 11 deletions
diff --git a/libc/misc/crypt.c b/libc/misc/crypt.c index 906dea2..db69325 100644 --- a/libc/misc/crypt.c +++ b/libc/misc/crypt.c @@ -1,42 +1,65 @@ -#include <features.h> -#include <stdlib.h> /* TEA based crypt(), version 0.0 <ndf@linux.mit.edu> * It looks like there are problems with key bits carrying through * to the encryted data, and I want to get rid of that libc call.. * This is just so rob could see it ;) */ + +/* + * I've: + * Compared the TEA implementation to a reference source - OK + * Noted the cycles count at 64 is twice the suggested value. + * Changed the types of 'n' and 'i' for better code with bcc. + * Removed a possible overrun of rkey by looping the values, it's now + * possible to _choose_ every bit of the 128bit PW with a 32 character word. + * Corrected the output transformation, it lost bits between words. + * Cleaned out all trace of the uncrypted PW from rkey. + * + * RDB. + */ + +#include <stdlib.h> + char * crypt(const char * key, const char * salt) { - /* n is the number of rounds, delta is a golden # derivative, - k is the key, v is the data to be encrypted. */ - unsigned long v[2], sum=0, delta=0x9e3779b9, n=64, k[4]; + /* n is the number of cycles (2 rounds/cycle), + delta is a golden # derivative, + k is the key, v is the data to be encrypted. */ + + unsigned long v[2], sum=0, delta=0x9e3779b9, k[4]; + int n=64, i, j; static char rkey[16]; - unsigned char i; /* Our constant string will be a string of zeros .. */ v[0]=v[1]=k[0]=k[1]=k[2]=k[3]=0; for(i=0;i<16;i++) rkey[i]=0; + rkey[0]=*salt; rkey[1]=salt[1]; - for (i=0;key[i];i++) rkey[i+1]=key[i]; + for (j=2,i=0;key[i];i++,j=((j+1)&15)) + rkey[j]=(rkey[j]<<4)+(rkey[j]>>4)+ key[i]; + memcpy(k, rkey, 4*sizeof(long)); - while (n-->0) { + while (n-->0) { sum += delta; v[0] += (v[1]<<4)+k[0] ^ v[1]+sum ^ (v[1]>>5)+k[1]; v[1] += (v[0]<<4)+k[2] ^ v[0]+sum ^ (v[0]>>5)+k[3]; } + /* Remove any trace of key */ + for(i=0;i<16;i++) rkey[i]=0; *rkey=*salt; rkey[1]=salt[1]; /* Now we need to unpack the bits and map it to "A-Za-z0-9./" for printing in /etc/passwd */ + sum=v[0]; for (i=2;i<13;i++) { /* This unpacks the 6 bit data, each cluster into its own byte */ - if (i==8) v[0]|=v[1]>>28; - rkey[i]=v[(i-2)/6]&0x3F; - v[(i-2)/6]>>=6; + rkey[i]=(sum&0x3F); + sum>>=6; + if(i==0+2) sum |= (v[1]<<26); + if(i==5+2) sum |= (v[1]>>4); /* Now we map to the proper chars */ if (rkey[i]>=0 && rkey[i]<12) rkey[i]+=46; |