Mercurial > dropbear
view fuzz.h @ 1715:3974f087d9c0
Disallow leading lines before the ident for server (#102)
Per RFC4253 4.2 clients must be able to process other lines of data
before the version string, server behavior is not defined neither
with MUST/SHOULD nor with MAY.
If server process up to 50 lines too - it may cause too long hanging
session with invalid/evil client that consume host resources and
potentially may lead to DDoS on poor embedded boxes.
Let's require first line from client to be version string and fail
early if it's not - matches both RFC and real OpenSSH behavior.
author | Vladislav Grishenko <themiron@users.noreply.github.com> |
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date | Mon, 15 Jun 2020 18:22:18 +0500 |
parents | 35af85194268 |
children | dfbe947bdf0d |
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#ifndef DROPBEAR_FUZZ_H #define DROPBEAR_FUZZ_H #include "config.h" #if DROPBEAR_FUZZ #include "includes.h" #include "buffer.h" #include "algo.h" #include "fuzz-wrapfd.h" // once per process void fuzz_common_setup(void); void fuzz_svr_setup(void); // must be called once per fuzz iteration. // returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE int fuzz_set_input(const uint8_t *Data, size_t Size); int fuzz_run_preauth(const uint8_t *Data, size_t Size, int skip_kexmaths); const void* fuzz_get_algo(const algo_type *algos, const char* name); // fuzzer functions that intrude into general code void fuzz_kex_fakealgos(void); int fuzz_checkpubkey_line(buffer* line, int line_num, char* filename, const char* algo, unsigned int algolen, const unsigned char* keyblob, unsigned int keybloblen); extern const char * const * fuzz_signkey_names; void fuzz_seed(void); void fuzz_get_socket_address(int fd, char **local_host, char **local_port, char **remote_host, char **remote_port, int host_lookup); void fuzz_fake_send_kexdh_reply(void); // fake IO wrappers #ifndef FUZZ_SKIP_WRAP #define select(nfds, readfds, writefds, exceptfds, timeout) \ wrapfd_select(nfds, readfds, writefds, exceptfds, timeout) #define write(fd, buf, count) wrapfd_write(fd, buf, count) #define read(fd, buf, count) wrapfd_read(fd, buf, count) #define close(fd) wrapfd_close(fd) #endif // FUZZ_SKIP_WRAP struct dropbear_fuzz_options { int fuzzing; // fuzzing input buffer *input; struct dropbear_cipher recv_cipher; struct dropbear_hash recv_mac; int wrapfds; // whether to skip slow bignum maths int skip_kexmaths; // dropbear_exit() jumps back int do_jmp; sigjmp_buf jmp; uid_t pw_uid; gid_t pw_gid; char* pw_name; char* pw_dir; char* pw_shell; char* pw_passwd; }; extern struct dropbear_fuzz_options fuzz; #endif // DROPBEAR_FUZZ #endif /* DROPBEAR_FUZZ_H */