Spyderhook

System call hooking library.

Compile

make [target] [options]

Target list:

target	description
default (no target defined)	Build the library (dynamic and static)
all	Build the library (dynamic and static)
install	install the library
uninstall	Delete files installed by "install" target
clean	Delete files generated by "default/all" target

Option list:

option	description
PREFIX	set prefix to install/uninstall files (default: /usr)
CFLAGS	set compiler flags
LDFLAGS	set linker flags

Compiling and install

$ make all
$ sudo make install

Linking

$ gcc mysource.c -lspyderhook -o dynamic-linked
$ gcc mysource.c -l:libspyderhook.a -o static-linked

Remove

$ sudo make uninstall

Example

here is a simple fakeroot program:

#include <spyderhook.h>
#include <sys/syscall.h>
#include <sys/ptrace.h>
#include <stdio.h>

int fakeroot(pidinfo_t *info, unsigned long nr, __attribute__((unused)) void *data){
    unsigned long second_parameter;

    switch(nr){
        case SYS_getuid:
        case SYS_geteuid:
        case SYS_getgid:
        case SYS_getegid:
            /* change the return register */
            sh_setreg(info->pid, SH_SYSCALL_RESULT, 0);
            break;

        case SYS_getgroups:
            /* getgroups(len, ptr) */
            sh_setreg(info->pid, SH_SYSCALL_RESULT, 1);
            second_parameter = sh_getreg(info->pid, SH_SECOND_ARG);
            if(second_parameter){
                ptrace(PTRACE_POKETEXT, info->pid, second_parameter, 0);
            }
            break;
    }

    return SH_CONTINUE;
}

int main(int argc, char **argv, char **envp){
    if(argc < 2){
        printf("fakeroot [filename] [args ...]\n");
        return 0;
    }

    int err;

    spyderhook_t *sh = sh_init();

    sh_setopt(sh, SHOPT_FILENAME, argv[1]);
    sh_setopt(sh, SHOPT_ARGV, argv+1);
    sh_setopt(sh, SHOPT_ENVP, envp);
    sh_setopt(sh, SHOPT_RESULT_CALLBACK, fakeroot);

    err = sh_mainloop(sh);
    if(err != SH_SUCCESS){
        printf("error => %d | %s\n", err, sh_strerror(err));
    }

    sh_free(sh);
    return 0;
}

testing:

$ id
uid=1000(nobody) gid=1000(nobody) groups=1000(nobody),998(wheel)
$ gcc fakeroot.c -o fakeroot -lspyderhook
$ ./fakeroot /bin/id
uid=0(root) gid=0(root) grupos=0(root)

Documentation

Someday ...

Contributing

You can help with code, or donating money. There is not a specific code style to follow, just 4 spaces for indentation.

paypal:

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