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- Hold the vnode lock throughout execve.

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- Set VV_TEXT in the top level execve code.
 - Fixup the image activators to deal with the newly locked vnode.
This commit is contained in:
Jeff Roberson 2002-08-13 06:55:28 +00:00
parent e9ed460af2
commit 619eb6e579
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=101771
8 changed files with 91 additions and 74 deletions
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14
sys/alpha/osf1/imgact_osf1.c
View File

@ -146,12 +146,11 @@ exec_osf1_imgact(struct image_params *imgp)
return(error);
}
if (imgp->vp) {
vrele(imgp->vp);
vput(imgp->vp);
/* leaking in the nameizone ??? XXX */
}
imgp->vp = ndp->ni_vp;
error = exec_map_first_page(imgp);
VOP_UNLOCK(imgp->vp, 0, FIRST_THREAD_IN_PROC(imgp->proc));
osf_auxargs->loader = "/compat/osf1/sbin/loader";
}
@ -188,17 +187,6 @@ exec_osf1_imgact(struct image_params *imgp)
imgp->interpreted = 0;
imgp->proc->p_sysent = &osf1_sysvec;
mp_fixme("Unlocked writecount and v_vflag access.");
if ((eap->tsize != 0 || eap->dsize != 0) &&
imgp->vp->v_writecount != 0) {
#ifdef DIAGNOSTIC
if (imgp->vp->v_vflag & VV_TEXT)
panic("exec: a VV_TEXT vnode has writecount != 0\n");
#endif
return ETXTBSY;
}
imgp->vp->v_vflag |= VV_TEXT;
/* set up text segment */
if ((error = vm_mmap(&vmspace->vm_map, &taddr, tsize,
VM_PROT_READ|VM_PROT_EXECUTE, VM_PROT_ALL, MAP_FIXED|MAP_COPY,

15
sys/compat/pecoff/imgact_pecoff.c
View File

@ -533,8 +533,6 @@ exec_pecoff_coff_prep_zmagic(struct image_params * imgp,
imgp->auxarg_size = sizeof(struct pecoff_args);
imgp->interpreted = 0;
mp_fixme("Unlocked vflag access.");
imgp->vp->v_vflag |= VV_TEXT;
if (sh != NULL)
free(sh, M_TEMP);
return 0;
@ -628,21 +626,26 @@ imgact_pecoff(struct image_params * imgp)
imgp->image_header;
struct coff_filehdr *fp;
int error, peofs;
struct thread *td = curthread;
error = pecoff_signature(FIRST_THREAD_IN_PROC(imgp->proc),
imgp->vp, dp);
if (error) {
return -1;
}
VOP_UNLOCK(imgp->vp, 0, td);
peofs = dp->d_peofs + sizeof(signature) - 1;
fp = malloc(PECOFF_HDR_SIZE, M_TEMP, M_WAITOK);
error = pecoff_read_from(FIRST_THREAD_IN_PROC(imgp->proc),
imgp->vp, peofs, (caddr_t) fp, PECOFF_HDR_SIZE);
if (error) {
free(fp, M_TEMP);
return error;
}
if (error)
goto fail;
error = exec_pecoff_coff_makecmds(imgp, fp, peofs);
fail:
free(fp, M_TEMP);
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td);
return error;
}

26
sys/compat/svr4/imgact_svr4.c
View File

@ -67,6 +67,7 @@ exec_svr4_imgact(imgp)
vm_offset_t buffer;
unsigned long bss_size;
int error;
struct thread *td = curthread;
if (((a_out->a_magic >> 16) & 0xff) != 0x64)
return -1;
@ -111,10 +112,12 @@ exec_svr4_imgact(imgp)
a_out->a_data + bss_size > imgp->proc->p_rlimit[RLIMIT_DATA].rlim_cur)
return (ENOMEM);
VOP_UNLOCK(imgp->vp, 0, td);
/* copy in arguments and/or environment from old process */
error = exec_extract_strings(imgp);
if (error)
return (error);
goto fail;
/*
* Destroy old process VM and create a new one (with a new stack)
@ -139,14 +142,14 @@ exec_svr4_imgact(imgp)
a_out->a_text + a_out->a_data + bss_size, FALSE,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (error)
return error;
goto fail;
error = vm_mmap(kernel_map, &buffer,
round_page(a_out->a_text + a_out->a_data + file_offset),
VM_PROT_READ, VM_PROT_READ, 0,
(caddr_t) imgp->vp, trunc_page(file_offset));
if (error)
return error;
goto fail;
error = copyout((caddr_t)(buffer + file_offset), (caddr_t)vmaddr,
a_out->a_text + a_out->a_data);
@ -155,7 +158,7 @@ exec_svr4_imgact(imgp)
buffer + round_page(a_out->a_text + a_out->a_data + file_offset));
if (error)
return error;
goto fail;
/*
* remove write enable on the 'text' part
@ -166,7 +169,7 @@ exec_svr4_imgact(imgp)
VM_PROT_EXECUTE|VM_PROT_READ,
TRUE);
if (error)
return error;
goto fail;
}
else {
#ifdef DEBUG
@ -183,7 +186,7 @@ exec_svr4_imgact(imgp)
MAP_PRIVATE | MAP_FIXED,
(caddr_t)imgp->vp, file_offset);
if (error)
return (error);
goto fail;
#ifdef DEBUG
printf("imgact: startaddr=%08lx, length=%08lx\n", (u_long)vmaddr,
@ -198,7 +201,7 @@ exec_svr4_imgact(imgp)
VM_PROT_ALL,
FALSE);
if (error)
return (error);
goto fail;
/*
* Allocate anon demand-zeroed area for uninitialized data
@ -208,16 +211,13 @@ exec_svr4_imgact(imgp)
error = vm_map_find(&vmspace->vm_map, NULL, 0, &vmaddr,
bss_size, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
if (error)
return (error);
goto fail;
#ifdef DEBUG
printf("imgact: bssaddr=%08lx, length=%08lx\n",
(u_long)vmaddr, bss_size);
#endif
}
/* Indicate that this file should not be modified */
mp_fixme("Unlocked vflag access.");
imgp->vp->v_vflag |= VV_TEXT;
}
/* Fill in process VM information */
vmspace->vm_tsize = round_page(a_out->a_text) >> PAGE_SHIFT;
@ -230,7 +230,9 @@ exec_svr4_imgact(imgp)
imgp->entry_addr = a_out->a_entry;
imgp->proc->p_sysent = &svr4_sysvec;
return (0);
fail:
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
return (error);
}
/*

22
sys/i386/ibcs2/imgact_coff.c
View File

@ -301,6 +301,7 @@ exec_coff_imgact(imgp)
unsigned long data_offset = 0, data_address = 0, data_size = 0;
unsigned long bss_size = 0;
caddr_t hole;
struct thread *td = curthread;
if (fhdr->f_magic != I386_COFF ||
!(fhdr->f_flags & F_EXEC)) {
@ -328,9 +329,11 @@ exec_coff_imgact(imgp)
((const char*)(imgp->image_header) + sizeof(struct filehdr) +
sizeof(struct aouthdr));
VOP_UNLOCK(imgp->vp, 0, td);
if ((error = exec_extract_strings(imgp)) != 0) {
DPRINTF(("%s(%d): return %d\n", __FILE__, __LINE__, error));
return error;
goto fail;
}
exec_new_vmspace(imgp, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS, USRSTACK);
@ -375,7 +378,8 @@ exec_coff_imgact(imgp)
0,
(caddr_t) imgp->vp,
foff)) != 0) {
return ENOEXEC;
error = ENOEXEC;
goto fail;
}
if(scns[i].s_size) {
char *libbuf;
@ -410,7 +414,7 @@ exec_coff_imgact(imgp)
(vm_offset_t) buf + len))
panic("exec_coff_imgact vm_map_remove failed");
if (error)
return error;
goto fail;
}
}
/*
@ -427,7 +431,7 @@ exec_coff_imgact(imgp)
text_size, text_size,
VM_PROT_READ | VM_PROT_EXECUTE)) != 0) {
DPRINTF(("%s(%d): error = %d\n", __FILE__, __LINE__, error));
return error;
goto fail;
}
/*
* Map in .data and .bss now
@ -445,7 +449,7 @@ exec_coff_imgact(imgp)
VM_PROT_ALL)) != 0) {
DPRINTF(("%s(%d): error = %d\n", __FILE__, __LINE__, error));
return error;
goto fail;
}
imgp->interpreted = 0;
@ -472,10 +476,10 @@ exec_coff_imgact(imgp)
ctob(vmspace->vm_dsize) + vmspace->vm_daddr ));
DPRINTF(("%s(%d): returning successfully!\n", __FILE__, __LINE__));
/* Indicate that this file should not be modified */
mp_fixme("Unlocked v_flag access");
imgp->vp->v_vflag |= VV_TEXT;
return 0;
fail:
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td);
return error;
}
/*

24
sys/i386/linux/imgact_linux.c
View File

@ -65,6 +65,7 @@ exec_linux_imgact(imgp)
unsigned long virtual_offset, file_offset;
vm_offset_t buffer;
unsigned long bss_size;
struct thread *td = curthread;
int error;
if (((a_out->a_magic >> 16) & 0xff) != 0x64)
@ -110,10 +111,12 @@ exec_linux_imgact(imgp)
a_out->a_data + bss_size > imgp->proc->p_rlimit[RLIMIT_DATA].rlim_cur)
return (ENOMEM);
VOP_UNLOCK(imgp->vp, 0, td);
/* copy in arguments and/or environment from old process */
error = exec_extract_strings(imgp);
if (error)
return (error);
goto fail;
/*
* Destroy old process VM and create a new one (with a new stack)
@ -138,14 +141,14 @@ exec_linux_imgact(imgp)
a_out->a_text + a_out->a_data + bss_size, FALSE,
VM_PROT_ALL, VM_PROT_ALL, 0);
if (error)
return error;
goto fail;
error = vm_mmap(kernel_map, &buffer,
round_page(a_out->a_text + a_out->a_data + file_offset),
VM_PROT_READ, VM_PROT_READ, 0,
(caddr_t) imgp->vp, trunc_page(file_offset));
if (error)
return error;
goto fail;
error = copyout((caddr_t)(void *)(uintptr_t)(buffer + file_offset),
(caddr_t)vmaddr, a_out->a_text + a_out->a_data);
@ -154,7 +157,7 @@ exec_linux_imgact(imgp)
buffer + round_page(a_out->a_text + a_out->a_data + file_offset));
if (error)
return error;
goto fail;
/*
* remove write enable on the 'text' part
@ -165,7 +168,7 @@ exec_linux_imgact(imgp)
VM_PROT_EXECUTE|VM_PROT_READ,
TRUE);
if (error)
return error;
goto fail;
}
else {
#ifdef DEBUG
@ -182,7 +185,7 @@ exec_linux_imgact(imgp)
MAP_PRIVATE | MAP_FIXED,
(caddr_t)imgp->vp, file_offset);
if (error)
return (error);
goto fail;
#ifdef DEBUG
printf("imgact: startaddr=%08lx, length=%08lx\n",
@ -197,7 +200,7 @@ exec_linux_imgact(imgp)
VM_PROT_ALL,
FALSE);
if (error)
return (error);
goto fail;
/*
* Allocate anon demand-zeroed area for uninitialized data
@ -207,7 +210,7 @@ exec_linux_imgact(imgp)
error = vm_map_find(&vmspace->vm_map, NULL, 0, &vmaddr,
bss_size, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
if (error)
return (error);
goto fail;
#ifdef DEBUG
printf("imgact: bssaddr=%08lx, length=%08lx\n",
(u_long)vmaddr, bss_size);
@ -230,7 +233,10 @@ exec_linux_imgact(imgp)
imgp->entry_addr = a_out->a_entry;
imgp->proc->p_sysent = &linux_sysvec;
return (0);
fail:
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td);
return (error);
}
/*

4
sys/kern/imgact_aout.c
View File

@ -239,10 +239,6 @@ exec_aout_imgact(imgp)
imgp->proc->p_sysent = &aout_sysvec;
/* Indicate that this file should not be modified */
mp_fixme("Unlocked vflag access.");
imgp->vp->v_vflag |= VV_TEXT;
return (0);
}

13
sys/kern/imgact_elf.c
View File

@ -599,6 +599,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
const char *interp = NULL;
Elf_Brandinfo *brand_info;
char *path;
struct thread *td = curthread;
GIANT_REQUIRED;
@ -624,16 +625,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
* From this point on, we may have resources that need to be freed.
*/
/*
* Yeah, I'm paranoid. There is every reason in the world to get
* VTEXT now since from here on out, there are places we can have
* a context switch. Better safe than sorry; I really don't want
* the file to change while it's being loaded.
*
* XXX We can't really set this flag safely without the vnode lock.
*/
mp_fixme("This needs the vnode lock to be safe.");
imgp->vp->v_vflag |= VV_TEXT;
VOP_UNLOCK(imgp->vp, 0, td);
if ((error = exec_extract_strings(imgp)) != 0)
goto fail;
@ -846,6 +838,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
imgp->interpreted = 0;
fail:
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td);
return error;
}

47
sys/kern/kern_exec.c
View File

@ -148,6 +148,7 @@ execve(td, uap)
#endif
struct vnode *textvp = NULL;
int credential_changing;
int textset;
imgp = &image_params;
@ -227,15 +228,23 @@ execve(td, uap)
* Check file permissions (also 'opens' file)
*/
error = exec_check_permissions(imgp);
if (error) {
VOP_UNLOCK(imgp->vp, 0, td);
if (error)
goto exec_fail_dealloc;
}
VOP_GETVOBJECT(imgp->vp, &imgp->object);
vm_object_reference(imgp->object);
if (VOP_GETVOBJECT(imgp->vp, &imgp->object) == 0)
vm_object_reference(imgp->object);
/*
* Set VV_TEXT now so no one can write to the executable while we're
* activating it.
*
* Remember if this was set before and unset it in case this is not
* actually an executable image.
*/
textset = imgp->vp->v_vflag & VV_TEXT;
imgp->vp->v_vflag |= VV_TEXT;
error = exec_map_first_page(imgp);
VOP_UNLOCK(imgp->vp, 0, td);
if (error)
goto exec_fail_dealloc;
@ -262,8 +271,11 @@ execve(td, uap)
}
if (error) {
if (error == -1)
if (error == -1) {
if (textset == 0)
imgp->vp->v_vflag &= ~VV_TEXT;
error = ENOEXEC;
}
goto exec_fail_dealloc;
}
@ -273,9 +285,16 @@ execve(td, uap)
*/
if (imgp->interpreted) {
exec_unmap_first_page(imgp);
/*
* VV_TEXT needs to be unset for scripts. There is a short
* period before we determine that something is a script where
* VV_TEXT will be set. The vnode lock is held over this
* entire period so nothing should illegitimately be blocked.
*/
imgp->vp->v_vflag &= ~VV_TEXT;
/* free name buffer and old vnode */
NDFREE(ndp, NDF_ONLY_PNBUF);
vrele(ndp->ni_vp);
vput(ndp->ni_vp);
vm_object_deallocate(imgp->object);
imgp->object = NULL;
/* set new name to that of the interpreter */
@ -329,6 +348,9 @@ execve(td, uap)
/* close files on exec */
fdcloseexec(td);
/* Get a reference to the vnode prior to locking the proc */
VREF(ndp->ni_vp);
/*
* For security and other reasons, signal handlers cannot
* be shared after an exec. The new process gets a copy of the old
@ -453,10 +475,10 @@ execve(td, uap)
}
/*
* Store the vp for use in procfs
* Store the vp for use in procfs. This vnode was referenced prior
* to locking the proc lock.
*/
textvp = p->p_textvp;
VREF(ndp->ni_vp);
p->p_textvp = ndp->ni_vp;
/*
@ -499,6 +521,7 @@ execve(td, uap)
done1:
PROC_UNLOCK(p);
/*
* Free any resources malloc'd earlier that we didn't use.
*/
@ -512,6 +535,8 @@ execve(td, uap)
*/
if (textvp != NULL)
vrele(textvp);
if (ndp->ni_vp && error != 0)
vrele(ndp->ni_vp);
#ifdef KTRACE
if (tracevp != NULL)
vrele(tracevp);
@ -535,7 +560,7 @@ execve(td, uap)
if (imgp->vp) {
NDFREE(ndp, NDF_ONLY_PNBUF);
vrele(imgp->vp);
vput(imgp->vp);
}
if (imgp->object)