Mercurial > dropbear
view libtomcrypt/src/encauth/ocb3/ocb3_decrypt.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. */ /** @file ocb3_decrypt.c OCB implementation, decrypt data, by Tom St Denis */ #include "tomcrypt.h" #ifdef LTC_OCB3_MODE /** Decrypt blocks of ciphertext with OCB @param ocb The OCB state @param ct The ciphertext (length multiple of the block size of the block cipher) @param ctlen The length of the input (octets) @param pt [out] The plaintext (length of ct) @return CRYPT_OK if successful */ int ocb3_decrypt(ocb3_state *ocb, const unsigned char *ct, unsigned long ctlen, unsigned char *pt) { unsigned char tmp[MAXBLOCKSIZE]; int err, i, full_blocks; unsigned char *pt_b, *ct_b; LTC_ARGCHK(ocb != NULL); if (ctlen == 0) return CRYPT_OK; /* no data, nothing to do */ LTC_ARGCHK(ct != NULL); LTC_ARGCHK(pt != NULL); if ((err = cipher_is_valid(ocb->cipher)) != CRYPT_OK) { return err; } if (ocb->block_len != cipher_descriptor[ocb->cipher].block_length) { return CRYPT_INVALID_ARG; } if (ctlen % ocb->block_len) { /* ctlen has to bu multiple of block_len */ return CRYPT_INVALID_ARG; } full_blocks = ctlen/ocb->block_len; for(i=0; i<full_blocks; i++) { pt_b = (unsigned char *)pt+i*ocb->block_len; ct_b = (unsigned char *)ct+i*ocb->block_len; /* ocb->Offset_current[] = ocb->Offset_current[] ^ Offset_{ntz(block_index)} */ ocb3_int_xor_blocks(ocb->Offset_current, ocb->Offset_current, ocb->L_[ocb3_int_ntz(ocb->block_index)], ocb->block_len); /* tmp[] = ct[] XOR ocb->Offset_current[] */ ocb3_int_xor_blocks(tmp, ct_b, ocb->Offset_current, ocb->block_len); /* decrypt */ if ((err = cipher_descriptor[ocb->cipher].ecb_decrypt(tmp, tmp, &ocb->key)) != CRYPT_OK) { goto LBL_ERR; } /* pt[] = tmp[] XOR ocb->Offset_current[] */ ocb3_int_xor_blocks(pt_b, tmp, ocb->Offset_current, ocb->block_len); /* ocb->checksum[] = ocb->checksum[] XOR pt[] */ ocb3_int_xor_blocks(ocb->checksum, ocb->checksum, pt_b, ocb->block_len); ocb->block_index++; } err = CRYPT_OK; LBL_ERR: #ifdef LTC_CLEAN_STACK zeromem(tmp, sizeof(tmp)); #endif return err; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */