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linuxolator: implement Linux' PROT_GROWSDOWN

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From the Linux man page for mprotect(2):
   PROT_GROWSDOWN
       Apply  the  protection  mode  down to the beginning of a mapping
       that grows downward (which should be a stack segment or a
       segment mapped with the MAP_GROWSDOWN flag set).

Reported by:	dchagin
Reviewed by:	alc, markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D41099
This commit is contained in:
Konstantin Belousov 2023-07-30 00:00:51 +03:00
parent 90049eabcf
commit 9b65fa6940
4 changed files with 18 additions and 10 deletions
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2
sys/compat/freebsd32/freebsd32_misc.c
View File

@ -512,7 +512,7 @@ freebsd32_mprotect(struct thread *td, struct freebsd32_mprotect_args *uap)
prot |= PROT_EXEC;
#endif
return (kern_mprotect(td, (uintptr_t)PTRIN(uap->addr), uap->len,
prot));
prot, 0));
}
int

14
sys/compat/linux/linux_mmap.c
View File

@ -229,16 +229,22 @@ linux_mmap_common(struct thread *td, uintptr_t addr, size_t len, int prot,
int
linux_mprotect_common(struct thread *td, uintptr_t addr, size_t len, int prot)
{
int flags = 0;
/* XXX Ignore PROT_GROWSDOWN and PROT_GROWSUP for now. */
prot &= ~(LINUX_PROT_GROWSDOWN | LINUX_PROT_GROWSUP);
if ((prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC)) != 0)
/* XXX Ignore PROT_GROWSUP for now. */
prot &= ~LINUX_PROT_GROWSUP;
if ((prot & ~(LINUX_PROT_GROWSDOWN | PROT_READ | PROT_WRITE |
PROT_EXEC)) != 0)
return (EINVAL);
if ((prot & LINUX_PROT_GROWSDOWN) != 0) {
prot &= ~LINUX_PROT_GROWSDOWN;
flags |= VM_MAP_PROTECT_GROWSDOWN;
}
#if defined(__amd64__)
linux_fixup_prot(td, &prot);
#endif
return (kern_mprotect(td, addr, len, prot));
return (kern_mprotect(td, addr, len, prot, flags));
}
/*

3
sys/sys/syscallsubr.h
View File

@ -216,7 +216,8 @@ int kern_mmap(struct thread *td, const struct mmap_req *mrp);
int kern_mmap_racct_check(struct thread *td, struct vm_map *map,
vm_size_t size);
int kern_mmap_maxprot(struct proc *p, int prot);
int kern_mprotect(struct thread *td, uintptr_t addr, size_t size, int prot);
int kern_mprotect(struct thread *td, uintptr_t addr, size_t size,
int prot, int flags);
int kern_msgctl(struct thread *, int, int, struct msqid_ds *);
int kern_msgrcv(struct thread *, int, void *, size_t, long, int, long *);
int kern_msgsnd(struct thread *, int, const void *, size_t, int, long);

9
sys/vm/vm_mmap.c
View File

@ -658,16 +658,17 @@ int
sys_mprotect(struct thread *td, struct mprotect_args *uap)
{
return (kern_mprotect(td, (uintptr_t)uap->addr, uap->len, uap->prot));
return (kern_mprotect(td, (uintptr_t)uap->addr, uap->len,
uap->prot, 0));
}
int
kern_mprotect(struct thread *td, uintptr_t addr0, size_t size, int prot)
kern_mprotect(struct thread *td, uintptr_t addr0, size_t size, int prot,
int flags)
{
vm_offset_t addr;
vm_size_t pageoff;
int vm_error, max_prot;
int flags;
addr = addr0;
if ((prot & ~(_PROT_ALL | PROT_MAX(_PROT_ALL))) != 0)
@ -687,7 +688,7 @@ kern_mprotect(struct thread *td, uintptr_t addr0, size_t size, int prot)
if (addr + size < addr)
return (EINVAL);
flags = VM_MAP_PROTECT_SET_PROT;
flags |= VM_MAP_PROTECT_SET_PROT;
if (max_prot != 0)
flags |= VM_MAP_PROTECT_SET_MAXPROT;
vm_error = vm_map_protect(&td->td_proc->p_vmspace->vm_map,