Mercurial > dropbear
view libtomcrypt/tests/no_prng.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 no_prng.c NO PRNG, Steffen Jaeckel */ #ifdef LTC_PKCS_1 typedef struct { struct ltc_prng_descriptor desc; char name[64]; unsigned char entropy[1024]; unsigned long len; unsigned long offset; } no_prng_desc_t; /** Start the PRNG @param prng [out] The PRNG state to initialize @return CRYPT_OK if successful */ int no_prng_start(prng_state *prng) { no_prng_desc_t *no_prng = (no_prng_desc_t*) prng; LTC_ARGCHK(no_prng != NULL); LTC_ARGCHK(no_prng->name == (char*)no_prng + offsetof(no_prng_desc_t, name)); no_prng->len = 0; no_prng->offset = 0; return CRYPT_OK; } /** Add entropy to the PRNG state @param in The data to add @param inlen Length of the data to add @param prng PRNG state to update @return CRYPT_OK if successful */ int no_prng_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng) { no_prng_desc_t *no_prng = (no_prng_desc_t*) prng; LTC_ARGCHK(no_prng != NULL); LTC_ARGCHK(no_prng->name == (char*)no_prng + offsetof(no_prng_desc_t, name)); LTC_ARGCHK(in != NULL); LTC_ARGCHK(inlen <= sizeof(no_prng->entropy)); no_prng->len = MIN(inlen, sizeof(no_prng->entropy)); memcpy(no_prng->entropy, in, no_prng->len); no_prng->offset = 0; return CRYPT_OK; } /** Make the PRNG ready to read from @param prng The PRNG to make active @return CRYPT_OK if successful */ int no_prng_ready(prng_state *prng) { LTC_ARGCHK(prng != NULL); return CRYPT_OK; } /** Read from the PRNG @param out Destination @param outlen Length of output @param prng The active PRNG to read from @return Number of octets read */ unsigned long no_prng_read(unsigned char *out, unsigned long outlen, prng_state *prng) { no_prng_desc_t *no_prng = (no_prng_desc_t*) prng; LTC_ARGCHK(no_prng != NULL); LTC_ARGCHK(no_prng->name == (char*)no_prng + offsetof(no_prng_desc_t, name)); LTC_ARGCHK(out != NULL); outlen = MIN(outlen, no_prng->len - no_prng->offset); memcpy(out, &no_prng->entropy[no_prng->offset], outlen); no_prng->offset += outlen; return outlen; } /** Terminate the PRNG @param prng The PRNG to terminate @return CRYPT_OK if successful */ int no_prng_done(prng_state *prng) { LTC_UNUSED_PARAM(prng); return CRYPT_OK; } /** Export the PRNG state @param out [out] Destination @param outlen [in/out] Max size and resulting size of the state @param prng The PRNG to export @return CRYPT_OK if successful */ int no_prng_export(unsigned char *out, unsigned long *outlen, prng_state *prng) { LTC_UNUSED_PARAM(out); LTC_UNUSED_PARAM(outlen); LTC_UNUSED_PARAM(prng); return CRYPT_OK; } /** Import a PRNG state @param in The PRNG state @param inlen Size of the state @param prng The PRNG to import @return CRYPT_OK if successful */ int no_prng_import(const unsigned char *in, unsigned long inlen, prng_state *prng) { LTC_UNUSED_PARAM(in); LTC_UNUSED_PARAM(inlen); LTC_UNUSED_PARAM(prng); return CRYPT_OK; } /** PRNG self-test @return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled */ int no_prng_test(void) { return CRYPT_OK; } static const struct ltc_prng_descriptor no_prng_desc = { NULL, 0, &no_prng_start, &no_prng_add_entropy, &no_prng_ready, &no_prng_read, &no_prng_done, &no_prng_export, &no_prng_import, &no_prng_test }; struct ltc_prng_descriptor* no_prng_desc_get(void) { no_prng_desc_t* no_prng = XMALLOC(sizeof(*no_prng)); LTC_ARGCHK(no_prng != NULL); XMEMCPY(&no_prng->desc, &no_prng_desc, sizeof(no_prng_desc)); LTC_ARGCHK(snprintf(no_prng->name, sizeof(no_prng->name), "no_prng@%p", no_prng) < (int)sizeof(no_prng->name)); no_prng->desc.name = no_prng->name; return &no_prng->desc; } void no_prng_desc_free(struct ltc_prng_descriptor* prng) { no_prng_desc_t *no_prng = (no_prng_desc_t*) prng; LTC_ARGCHK(no_prng != NULL); LTC_ARGCHK(no_prng->name == (char*)no_prng + offsetof(no_prng_desc_t, name)); XFREE(no_prng); } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */