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Change the check for 'size' wrapping around to zero in kern_mmap to account

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for both the lower and upper bound modifications. Change the error returned
to ENOMEM. Rename the parameter size to len and make size a local variable
that stores the value of len after it has been modified.

This addresses concerns expressed by Bruce Evans after r348843.

Reported by: brde@optusnet.com.au
Reviewed by: kib, markj (mentors)
MFC after: 3 days
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D20592
This commit is contained in:
Doug Moore 2019-06-10 21:26:14 +00:00
parent 0422393286
commit 77555b849d
2 changed files with 10 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/sys/syscallsubr.h
View File

@ -173,7 +173,7 @@ int kern_mknodat(struct thread *td, int fd, const char *path,
enum uio_seg pathseg, int mode, dev_t dev);
int kern_mlock(struct proc *proc, struct ucred *cred, uintptr_t addr,
size_t len);
int kern_mmap(struct thread *td, uintptr_t addr, size_t size, int prot,
int kern_mmap(struct thread *td, uintptr_t addr, size_t len, int prot,
int flags, int fd, off_t pos);
int kern_mprotect(struct thread *td, uintptr_t addr, size_t size, int prot);
int kern_msgctl(struct thread *, int, int, struct msqid_ds *);

18
sys/vm/vm_mmap.c
View File

@ -179,13 +179,13 @@ sys_mmap(struct thread *td, struct mmap_args *uap)
}
int
kern_mmap(struct thread *td, uintptr_t addr0, size_t size, int prot, int flags,
kern_mmap(struct thread *td, uintptr_t addr0, size_t len, int prot, int flags,
int fd, off_t pos)
{
struct vmspace *vms;
struct file *fp;
vm_offset_t addr;
vm_size_t pageoff;
vm_size_t pageoff, size;
vm_prot_t cap_maxprot;
int align, error;
cap_rights_t rights;
@ -210,7 +210,7 @@ kern_mmap(struct thread *td, uintptr_t addr0, size_t size, int prot, int flags,
* pos.
*/
if (!SV_CURPROC_FLAG(SV_AOUT)) {
if ((size == 0 && curproc->p_osrel >= P_OSREL_MAP_ANON) ||
if ((len == 0 && curproc->p_osrel >= P_OSREL_MAP_ANON) ||
((flags & MAP_ANON) != 0 && (fd != -1 || pos != 0)))
return (EINVAL);
} else {
@ -255,12 +255,12 @@ kern_mmap(struct thread *td, uintptr_t addr0, size_t size, int prot, int flags,
pageoff = (pos & PAGE_MASK);
pos -= pageoff;
/* Adjust size for rounding (on both ends). */
size += pageoff; /* low end... */
/* Check for rounding up to zero. */
if (round_page(size) < size)
return (EINVAL);
/* Compute size from len by rounding (on both ends). */
size = len + pageoff; /* low end... */
size = round_page(size); /* hi end */
/* Check for rounding up to zero. */
if (len < size)
return (ENOMEM);
/* Ensure alignment is at least a page and fits in a pointer. */
align = flags & MAP_ALIGNMENT_MASK;
@ -317,7 +317,7 @@ kern_mmap(struct thread *td, uintptr_t addr0, size_t size, int prot, int flags,
addr = round_page((vm_offset_t)vms->vm_daddr +
lim_max(td, RLIMIT_DATA));
}
if (size == 0) {
if (len == 0) {
/*
* Return success without mapping anything for old
* binaries that request a page-aligned mapping of