Mercurial > dropbear
view libtomcrypt/src/mac/hmac/hmac_done.c @ 1930:299f4f19ba19
Add /usr/sbin and /sbin to default root PATH
When dropbear is used in a very restricted environment (such as in a
initrd), the default user shell is often also very restricted
and doesn't take care of setting the PATH so the user ends up
with the PATH set by dropbear. Unfortunately, dropbear always
sets "/usr/bin:/bin" as default PATH even for the root user
which should have /usr/sbin and /sbin too.
For a concrete instance of this problem, see the "Remote Unlocking"
section in this tutorial: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/
It speaks of a bug in the initramfs script because it's written "blkid"
instead of "/sbin/blkid"... this is just because the scripts from the
initramfs do not expect to have a PATH without the sbin directories and
because dropbear is not setting the PATH appropriately for the root user.
I'm thus suggesting to use the attached patch to fix this misbehaviour (I
did not test it, but it's easy enough). It might seem anecdotic but
multiple Kali users have been bitten by this.
From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
author | Raphael Hertzog <hertzog@debian.org> |
---|---|
date | Mon, 09 Jul 2018 16:27:53 +0200 |
parents | 6dba84798cd5 |
children |
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. */ #include "tomcrypt.h" /** @file hmac_done.c HMAC support, terminate stream, Tom St Denis/Dobes Vandermeer */ #ifdef LTC_HMAC #define LTC_HMAC_BLOCKSIZE hash_descriptor[hash].blocksize /** Terminate an HMAC session @param hmac The HMAC state @param out [out] The destination of the HMAC authentication tag @param outlen [in/out] The max size and resulting size of the HMAC authentication tag @return CRYPT_OK if successful */ int hmac_done(hmac_state *hmac, unsigned char *out, unsigned long *outlen) { unsigned char buf[MAXBLOCKSIZE], isha[MAXBLOCKSIZE]; unsigned long hashsize, i; int hash, err; LTC_ARGCHK(hmac != NULL); LTC_ARGCHK(out != NULL); /* test hash */ hash = hmac->hash; if((err = hash_is_valid(hash)) != CRYPT_OK) { return err; } /* get the hash message digest size */ hashsize = hash_descriptor[hash].hashsize; if ((err = hash_descriptor[hash].done(&hmac->md, isha)) != CRYPT_OK) { goto LBL_ERR; } /* Create the second HMAC vector vector for step (3) */ for(i=0; i < LTC_HMAC_BLOCKSIZE; i++) { buf[i] = hmac->key[i] ^ 0x5C; } /* Now calculate the "outer" hash for step (5), (6), and (7) */ if ((err = hash_descriptor[hash].init(&hmac->md)) != CRYPT_OK) { goto LBL_ERR; } if ((err = hash_descriptor[hash].process(&hmac->md, buf, LTC_HMAC_BLOCKSIZE)) != CRYPT_OK) { goto LBL_ERR; } if ((err = hash_descriptor[hash].process(&hmac->md, isha, hashsize)) != CRYPT_OK) { goto LBL_ERR; } if ((err = hash_descriptor[hash].done(&hmac->md, buf)) != CRYPT_OK) { goto LBL_ERR; } /* copy to output */ for (i = 0; i < hashsize && i < *outlen; i++) { out[i] = buf[i]; } *outlen = i; err = CRYPT_OK; LBL_ERR: XFREE(hmac->key); #ifdef LTC_CLEAN_STACK zeromem(isha, hashsize); zeromem(buf, hashsize); zeromem(hmac, sizeof(*hmac)); #endif return err; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */