* Removed startup code patches in lib/csu regarding kernel to userland ABI. * Aligned stack layout on NetBSD stack layout. * Generate valid stack pointers instead of offsets by taking into account _minix_kerninfo->kinfo->user_sp. * Refactored stack generation, by moving part of execve in two functions {minix_stack_params(), minix_stack_fill()} and using them in execve(), rs and vm. * Changed load offset of rtld (ld.so) to: execi.args.stack_high - execi.args.stack_size - 0xa00000 which is 10MB below the main executable stack. Change-Id: I839daf3de43321cded44105634102d419cb36cec
204 lines
5.8 KiB
C
204 lines
5.8 KiB
C
/* This file handles the EXEC system call. It performs the work as follows:
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* - see if the permissions allow the file to be executed
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* - read the header and extract the sizes
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* - fetch the initial args and environment from the user space
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* - allocate the memory for the new process
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* - copy the initial stack from PM to the process
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* - read in the text and data segments and copy to the process
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* - take care of setuid and setgid bits
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* - fix up 'mproc' table
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* - tell kernel about EXEC
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* - save offset to initial argc (for procfs)
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*
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* The entry points into this file are:
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* do_exec: perform the EXEC system call
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* do_newexec: handle PM part of exec call after VFS
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* do_execrestart: finish the special exec call for RS
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* exec_restart: finish a regular exec call
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*/
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#include "pm.h"
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#include <sys/stat.h>
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#include <minix/callnr.h>
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#include <minix/endpoint.h>
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#include <minix/com.h>
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#include <minix/vm.h>
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#include <signal.h>
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#include <string.h>
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#include <libexec.h>
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#include <sys/ptrace.h>
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#include "mproc.h"
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#include "param.h"
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#define ESCRIPT (-2000) /* Returned by read_header for a #! script. */
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#define PTRSIZE sizeof(char *) /* Size of pointers in argv[] and envp[]. */
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/*===========================================================================*
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* do_exec *
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*===========================================================================*/
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int do_exec()
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{
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message m;
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/* Forward call to VFS */
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m.m_type = PM_EXEC;
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m.PM_PROC = mp->mp_endpoint;
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m.PM_PATH = m_in.exec_name;
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m.PM_PATH_LEN = m_in.exec_len;
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m.PM_FRAME = m_in.frame_ptr;
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m.PM_FRAME_LEN = m_in.msg_frame_len;
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m.PM_EXECFLAGS = m_in.PMEXEC_FLAGS;
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m.PM_PS_STR = (vir_bytes)m_in.m1_p4; /* ps_strings pointer into the frame. */
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tell_vfs(mp, &m);
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/* Do not reply */
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return SUSPEND;
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}
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/*===========================================================================*
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* do_newexec *
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*===========================================================================*/
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int do_newexec(void)
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{
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int proc_e, proc_n, allow_setuid;
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char *ptr;
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struct mproc *rmp;
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struct exec_info args;
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int r, flags = 0;
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if (who_e != VFS_PROC_NR && who_e != RS_PROC_NR)
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return EPERM;
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proc_e= m_in.EXC_NM_PROC;
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if (pm_isokendpt(proc_e, &proc_n) != OK) {
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panic("do_newexec: got bad endpoint: %d", proc_e);
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}
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rmp= &mproc[proc_n];
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ptr= m_in.EXC_NM_PTR;
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r= sys_datacopy(who_e, (vir_bytes)ptr,
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SELF, (vir_bytes)&args, sizeof(args));
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if (r != OK)
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panic("do_newexec: sys_datacopy failed: %d", r);
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allow_setuid = 0; /* Do not allow setuid execution */
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rmp->mp_flags &= ~TAINTED; /* By default not tainted */
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if (rmp->mp_tracer == NO_TRACER) {
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/* Okay, setuid execution is allowed */
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allow_setuid = 1;
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}
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if (allow_setuid && args.allow_setuid) {
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rmp->mp_effuid = args.new_uid;
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rmp->mp_effgid = args.new_gid;
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}
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/* A process is considered 'tainted' when it's executing with
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* setuid or setgid bit set, or when the real{u,g}id doesn't
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* match the eff{u,g}id, respectively. */
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if (allow_setuid && args.allow_setuid) {
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/* Program has setuid and/or setgid bits set */
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rmp->mp_flags |= TAINTED;
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} else if (rmp->mp_effuid != rmp->mp_realuid ||
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rmp->mp_effgid != rmp->mp_realgid) {
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rmp->mp_flags |= TAINTED;
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}
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/* System will save command line for debugging, ps(1) output, etc. */
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strncpy(rmp->mp_name, args.progname, PROC_NAME_LEN-1);
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rmp->mp_name[PROC_NAME_LEN-1] = '\0';
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/* Save offset to initial argc (for procfs) */
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rmp->mp_frame_addr = (vir_bytes) args.stack_high - args.frame_len;
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rmp->mp_frame_len = args.frame_len;
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/* Kill process if something goes wrong after this point. */
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rmp->mp_flags |= PARTIAL_EXEC;
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mp->mp_reply.reply_res2= (vir_bytes) rmp->mp_frame_addr;
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mp->mp_reply.reply_res3= flags;
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if (allow_setuid && args.allow_setuid)
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mp->mp_reply.reply_res3 |= EXC_NM_RF_ALLOW_SETUID;
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return r;
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}
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/*===========================================================================*
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* do_execrestart *
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*===========================================================================*/
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int do_execrestart(void)
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{
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int proc_e, proc_n, result;
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struct mproc *rmp;
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vir_bytes pc, ps_str;
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if (who_e != RS_PROC_NR)
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return EPERM;
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proc_e = m_in.EXC_RS_PROC;
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if (pm_isokendpt(proc_e, &proc_n) != OK) {
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panic("do_execrestart: got bad endpoint: %d", proc_e);
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}
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rmp = &mproc[proc_n];
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result = m_in.EXC_RS_RESULT;
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pc = (vir_bytes)m_in.EXC_RS_PC;
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ps_str = (vir_bytes)m_in.EXC_RS_PS_STR;
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exec_restart(rmp, result, pc, rmp->mp_frame_addr, ps_str);
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return OK;
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}
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/*===========================================================================*
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* exec_restart *
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*===========================================================================*/
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void exec_restart(struct mproc *rmp, int result, vir_bytes pc, vir_bytes sp,
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vir_bytes ps_str)
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{
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int r, sn;
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if (result != OK)
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{
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if (rmp->mp_flags & PARTIAL_EXEC)
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{
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/* Use SIGKILL to signal that something went wrong */
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sys_kill(rmp->mp_endpoint, SIGKILL);
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return;
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}
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setreply(rmp-mproc, result);
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return;
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}
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rmp->mp_flags &= ~PARTIAL_EXEC;
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/* Fix 'mproc' fields, tell kernel that exec is done, reset caught
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* sigs.
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*/
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for (sn = 1; sn < _NSIG; sn++) {
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if (sigismember(&rmp->mp_catch, sn)) {
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sigdelset(&rmp->mp_catch, sn);
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rmp->mp_sigact[sn].sa_handler = SIG_DFL;
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sigemptyset(&rmp->mp_sigact[sn].sa_mask);
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}
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}
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/* Cause a signal if this process is traced.
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* Do this before making the process runnable again!
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*/
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#if USE_TRACE
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if (rmp->mp_tracer != NO_TRACER && !(rmp->mp_trace_flags & TO_NOEXEC))
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{
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sn = (rmp->mp_trace_flags & TO_ALTEXEC) ? SIGSTOP : SIGTRAP;
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check_sig(rmp->mp_pid, sn, FALSE /* ksig */);
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}
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#endif /* USE_TRACE */
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/* Call kernel to exec with SP and PC set by VFS. */
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r = sys_exec(rmp->mp_endpoint, (char *) sp, rmp->mp_name, pc, ps_str);
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if (r != OK) panic("sys_exec failed: %d", r);
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}
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