Mercurial > dropbear
annotate fuzz/fuzzer-kexdh.c @ 1885:5d8dbb6fdab7
Fix SSH_PUBKEYINFO, limit characters, add tests
We fix a bad_bufptr() failure from a previous commit. We now limit
the allowed characters to those that will definitely be safe
in a shell. Some scripts/programs may use arbitrary environment
variables without escaping correctly - that could be a problem
in a restricted environment.
The current allowed set is a-z A-Z 0-9 .,_-+@
This also adds a test for SSH_PUBKEYINFO, by default it only runs
under github actions (or "act -j build").
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Wed, 16 Mar 2022 17:17:23 +0800 |
| parents | 0cc85b4a4abb |
| children |
| rev | line source |
|---|---|
| 1589 | 1 #include "fuzz.h" |
| 2 #include "session.h" | |
| 3 #include "fuzz-wrapfd.h" | |
| 4 #include "debug.h" | |
| 5 #include "runopts.h" | |
| 6 #include "algo.h" | |
| 7 #include "bignum.h" | |
| 8 | |
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9 static struct key_context* keep_newkeys = NULL; |
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10 #define NUM_PARAMS 80 |
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parents:
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11 static struct kex_dh_param *dh_params[NUM_PARAMS]; |
| 1589 | 12 |
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13 static void setup() __attribute__((constructor)); |
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Matt Johnston <matt@ucc.asn.au>
parents:
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diff
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14 // Perform initial setup here to avoid hitting timeouts on first run |
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Move fuzzer-kex initialisation into a constructor function
Matt Johnston <matt@ucc.asn.au>
parents:
1756
diff
changeset
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15 static void setup() { |
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Matt Johnston <matt@ucc.asn.au>
parents:
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16 fuzz_common_setup(); |
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parents:
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17 fuzz_svr_setup(); |
| 1589 | 18 |
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parents:
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diff
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19 keep_newkeys = (struct key_context*)m_malloc(sizeof(struct key_context)); |
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parents:
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20 keep_newkeys->algo_kex = fuzz_get_algo(sshkex, "diffie-hellman-group14-sha256"); |
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parents:
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21 keep_newkeys->algo_hostkey = DROPBEAR_SIGNKEY_ECDSA_NISTP256; |
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parents:
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22 ses.newkeys = keep_newkeys; |
| 1589 | 23 |
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24 /* Pre-generate parameters */ |
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25 int i; |
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26 for (i = 0; i < NUM_PARAMS; i++) { |
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27 dh_params[i] = gen_kexdh_param(); |
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28 } |
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29 } |
| 1589 | 30 |
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31 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { |
| 1589 | 32 if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) { |
| 33 return 0; | |
| 34 } | |
| 35 | |
| 36 m_malloc_set_epoch(1); | |
| 37 | |
| 38 if (setjmp(fuzz.jmp) == 0) { | |
| 39 /* Based on recv_msg_kexdh_init()/send_msg_kexdh_reply() | |
| 40 with DROPBEAR_KEX_NORMAL_DH */ | |
| 41 ses.newkeys = keep_newkeys; | |
| 42 | |
| 43 /* Choose from the collection of ecdh params */ | |
| 44 unsigned int e = buf_getint(fuzz.input); | |
| 45 struct kex_dh_param * dh_param = dh_params[e % NUM_PARAMS]; | |
| 46 | |
| 47 DEF_MP_INT(dh_e); | |
| 48 m_mp_init(&dh_e); | |
| 49 if (buf_getmpint(fuzz.input, &dh_e) != DROPBEAR_SUCCESS) { | |
| 50 dropbear_exit("Bad kex value"); | |
| 51 } | |
| 52 | |
|
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kexhashbuf was much to small in kex fuzzers
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53 ses.kexhashbuf = buf_new(KEXHASHBUF_MAX_INTS); |
| 1589 | 54 kexdh_comb_key(dh_param, &dh_e, svr_opts.hostkey); |
| 55 | |
| 1609 | 56 mp_clear(ses.dh_K); |
| 1589 | 57 m_free(ses.dh_K); |
| 58 mp_clear(&dh_e); | |
| 59 | |
| 1609 | 60 buf_free(ses.hash); |
| 61 buf_free(ses.session_id); | |
| 62 /* kexhashbuf is freed in kexdh_comb_key */ | |
| 63 | |
| 1589 | 64 m_malloc_free_epoch(1, 0); |
| 65 } else { | |
| 66 m_malloc_free_epoch(1, 1); | |
| 67 TRACE(("dropbear_exit longjmped")) | |
| 68 /* dropbear_exit jumped here */ | |
| 69 } | |
| 70 | |
| 71 return 0; | |
| 72 } |