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Implement the fexecve(2) syscall.

Browse Source 
Based on the submission by rdivacky,
	sponsored by Google Summer of Code 2007
Reviewed by:	rwatson, rdivacky
Tested by:	pho
This commit is contained in:
Konstantin Belousov 2008-03-31 12:05:52 +00:00
parent e4193f25cb
commit 632dbc19e2
2 changed files with 78 additions and 28 deletions
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105
sys/kern/kern_exec.c
View File

@ -188,6 +188,28 @@ execve(td, uap)
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct fexecve_args {
int fd;
char **argv;
char **envv;
}
#endif
int
fexecve(struct thread *td, struct fexecve_args *uap)
{
int error;
struct image_args args;
error = exec_copyin_args(&args, NULL, UIO_SYSSPACE,
uap->argv, uap->envv);
if (error == 0) {
args.fd = uap->fd;
error = kern_execve(td, &args, NULL);
}
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct __mac_execve_args {
char *fname;
@ -284,7 +306,7 @@ do_execve(td, args, mac_p)
struct ucred *newcred = NULL, *oldcred;
struct uidinfo *euip;
register_t *stack_base;
int error, len, i;
int error, len = 0, i;
struct image_params image_params, *imgp;
struct vattr attr;
int (*img_first)(struct image_params *);
@ -294,7 +316,7 @@ do_execve(td, args, mac_p)
struct vnode *tracevp = NULL;
struct ucred *tracecred = NULL;
#endif
struct vnode *textvp = NULL;
struct vnode *textvp = NULL, *binvp = NULL;
int credential_changing;
int vfslocked;
int textset;
@ -305,6 +327,7 @@ do_execve(td, args, mac_p)
#ifdef HWPMC_HOOKS
struct pmckern_procexec pe;
#endif
static const char fexecv_proc_title[] = "(fexecv)";
vfslocked = 0;
imgp = &image_params;
@ -355,17 +378,29 @@ do_execve(td, args, mac_p)
* XXXAUDIT: It would be desirable to also audit the name of the
* interpreter if this is an interpreted binary.
*/
ndp = &nd;
NDINIT(ndp, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME | MPSAFE |
AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
if (args->fname != NULL) {
ndp = &nd;
NDINIT(ndp, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME
| MPSAFE | AUDITVNODE1, UIO_SYSSPACE, args->fname, td);
}
interpret:
error = namei(ndp);
if (error)
goto exec_fail;
if (args->fname != NULL) {
error = namei(ndp);
if (error)
goto exec_fail;
vfslocked = NDHASGIANT(ndp);
imgp->vp = ndp->ni_vp;
vfslocked = NDHASGIANT(ndp);
binvp = ndp->ni_vp;
imgp->vp = binvp;
} else {
error = fgetvp(td, args->fd, &binvp);
if (error)
goto exec_fail;
vfslocked = VFS_LOCK_GIANT(binvp->v_mount);
vn_lock(binvp, LK_EXCLUSIVE | LK_RETRY);
imgp->vp = binvp;
}
/*
* Check file permissions (also 'opens' file)
@ -438,12 +473,13 @@ do_execve(td, args, mac_p)
*/
imgp->vp->v_vflag &= ~VV_TEXT;
/* free name buffer and old vnode */
NDFREE(ndp, NDF_ONLY_PNBUF);
if (args->fname != NULL)
NDFREE(ndp, NDF_ONLY_PNBUF);
#ifdef MAC
interplabel = mac_vnode_label_alloc();
mac_vnode_copy_label(ndp->ni_vp->v_label, interplabel);
mac_vnode_copy_label(binvp->v_label, interplabel);
#endif
vput(ndp->ni_vp);
vput(binvp);
vm_object_deallocate(imgp->object);
imgp->object = NULL;
VFS_UNLOCK_GIANT(vfslocked);
@ -451,6 +487,7 @@ do_execve(td, args, mac_p)
/* set new name to that of the interpreter */
NDINIT(ndp, LOOKUP, LOCKLEAF | FOLLOW | SAVENAME | MPSAFE,
UIO_SYSSPACE, imgp->interpreter_name, td);
args->fname = imgp->interpreter_name;
goto interpret;
}
@ -496,7 +533,7 @@ do_execve(td, args, mac_p)
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
/* Get a reference to the vnode prior to locking the proc */
VREF(ndp->ni_vp);
VREF(binvp);
/*
* For security and other reasons, signal handlers cannot
@ -522,8 +559,18 @@ do_execve(td, args, mac_p)
execsigs(p);
/* name this process - nameiexec(p, ndp) */
len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
if (args->fname) {
len = min(ndp->ni_cnd.cn_namelen,MAXCOMLEN);
bcopy(ndp->ni_cnd.cn_nameptr, p->p_comm, len);
} else {
len = MAXCOMLEN;
if (vn_commname(binvp, p->p_comm, MAXCOMLEN + 1) == 0)
len = MAXCOMLEN;
else {
len = sizeof(fexecv_proc_title);
bcopy(fexecv_proc_title, p->p_comm, len);
}
}
p->p_comm[len] = 0;
bcopy(p->p_comm, td->td_name, sizeof(td->td_name));
@ -653,7 +700,7 @@ do_execve(td, args, mac_p)
* to locking the proc lock.
*/
textvp = p->p_textvp;
p->p_textvp = ndp->ni_vp;
p->p_textvp = binvp;
/*
* Notify others that we exec'd, and clear the P_INEXEC flag
@ -736,8 +783,8 @@ do_execve(td, args, mac_p)
vrele(textvp);
VFS_UNLOCK_GIANT(tvfslocked);
}
if (ndp->ni_vp && error != 0)
vrele(ndp->ni_vp);
if (binvp && error != 0)
vrele(binvp);
#ifdef KTRACE
if (tracevp != NULL) {
int tvfslocked;
@ -766,7 +813,8 @@ do_execve(td, args, mac_p)
exec_unmap_first_page(imgp);
if (imgp->vp != NULL) {
NDFREE(ndp, NDF_ONLY_PNBUF);
if (args->fname)
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(imgp->vp);
}
@ -991,17 +1039,18 @@ exec_copyin_args(struct image_args *args, char *fname,
args->begin_argv = args->buf;
args->endp = args->begin_argv;
args->stringspace = ARG_MAX;
args->fname = args->buf + ARG_MAX;
/*
* Copy the file name.
*/
error = (segflg == UIO_SYSSPACE) ?
copystr(fname, args->fname, PATH_MAX, &length) :
copyinstr(fname, args->fname, PATH_MAX, &length);
if (error != 0)
goto err_exit;
if (fname != NULL) {
args->fname = args->buf + ARG_MAX;
error = (segflg == UIO_SYSSPACE) ?
copystr(fname, args->fname, PATH_MAX, &length) :
copyinstr(fname, args->fname, PATH_MAX, &length);
if (error != 0)
goto err_exit;
} else
args->fname = NULL;
/*
* extract arguments first

1
sys/sys/imgact.h
View File

@ -45,6 +45,7 @@ struct image_args {
int stringspace; /* space left in arg & env buffer */
int argc; /* count of argument strings */
int envc; /* count of environment strings */
int fd; /* file descriptor of the executable */
};
struct image_params {