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mm/mseal: small cleanups

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Drop the wholly unnecessary set_vma_sealed() helper(), which is used only
once, and place VMA_ITERATOR() declarations in the correct place.

Retain vma_is_sealed(), and use it instead of the confusingly named
can_modify_vma(), so it's abundantly clear what's being tested, rather
then a nebulous sense of 'can the VMA be modified'.

No functional change intended.

Link: https://lkml.kernel.org/r/98cf28d04583d632a6eb698e9ad23733bb6af26b.1753431105.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Jeff Xu <jeffxu@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Lorenzo Stoakes 2025-07-25 09:29:43 +01:00 committed by Andrew Morton
parent d0b47a6866
commit 8b2914162a
6 changed files with 8 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
mm/madvise.c
View File

@ -1287,7 +1287,7 @@ static bool can_madvise_modify(struct madvise_behavior *madv_behavior)
struct vm_area_struct *vma = madv_behavior->vma; struct vm_area_struct *vma = madv_behavior->vma;
/* If the VMA isn't sealed we're good. */ /* If the VMA isn't sealed we're good. */
if (can_modify_vma(vma)) if (!vma_is_sealed(vma))
return true; return true;
/* For a sealed VMA, we only care about discard operations. */ /* For a sealed VMA, we only care about discard operations. */

2
mm/mprotect.c
View File

@ -766,7 +766,7 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
unsigned long charged = 0; unsigned long charged = 0;
int error; int error;
if (!can_modify_vma(vma)) if (vma_is_sealed(vma))
return -EPERM; return -EPERM;
if (newflags == oldflags) { if (newflags == oldflags) {

2
mm/mremap.c
View File

@ -1651,7 +1651,7 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
return -EFAULT; return -EFAULT;
/* If mseal()'d, mremap() is prohibited. */ /* If mseal()'d, mremap() is prohibited. */
if (!can_modify_vma(vma)) if (vma_is_sealed(vma))
return -EPERM; return -EPERM;
/* Align to hugetlb page size, if required. */ /* Align to hugetlb page size, if required. */

9
mm/mseal.c
View File

@ -15,11 +15,6 @@
#include <linux/sched.h> #include <linux/sched.h>
#include "internal.h" #include "internal.h"
static inline void set_vma_sealed(struct vm_area_struct *vma)
{
vm_flags_set(vma, VM_SEALED);
}
static int mseal_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma, static int mseal_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct vm_area_struct **prev, unsigned long start, struct vm_area_struct **prev, unsigned long start,
unsigned long end, vm_flags_t newflags) unsigned long end, vm_flags_t newflags)
@ -36,7 +31,7 @@ static int mseal_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma,
goto out; goto out;
} }
set_vma_sealed(vma); vm_flags_set(vma, VM_SEALED);
out: out:
*prev = vma; *prev = vma;
return ret; return ret;
@ -53,7 +48,6 @@ static int check_mm_seal(unsigned long start, unsigned long end)
{ {
struct vm_area_struct *vma; struct vm_area_struct *vma;
unsigned long nstart = start; unsigned long nstart = start;
VMA_ITERATOR(vmi, current->mm, start); VMA_ITERATOR(vmi, current->mm, start);
/* going through each vma to check. */ /* going through each vma to check. */
@ -78,7 +72,6 @@ static int apply_mm_seal(unsigned long start, unsigned long end)
{ {
unsigned long nstart; unsigned long nstart;
struct vm_area_struct *vma, *prev; struct vm_area_struct *vma, *prev;
VMA_ITERATOR(vmi, current->mm, start); VMA_ITERATOR(vmi, current->mm, start);
vma = vma_iter_load(&vmi); vma = vma_iter_load(&vmi);

4
mm/vma.c
View File

@ -1351,7 +1351,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
} }
/* Don't bother splitting the VMA if we can't unmap it anyway */ /* Don't bother splitting the VMA if we can't unmap it anyway */
if (!can_modify_vma(vms->vma)) { if (vma_is_sealed(vms->vma)) {
error = -EPERM; error = -EPERM;
goto start_split_failed; goto start_split_failed;
} }
@ -1371,7 +1371,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
for_each_vma_range(*(vms->vmi), next, vms->end) { for_each_vma_range(*(vms->vmi), next, vms->end) {
long nrpages; long nrpages;
if (!can_modify_vma(next)) { if (vma_is_sealed(next)) {
error = -EPERM; error = -EPERM;
goto modify_vma_failed; goto modify_vma_failed;
} }

20
mm/vma.h
View File

@ -559,31 +559,15 @@ struct vm_area_struct *vma_iter_next_rewind(struct vma_iterator *vmi,
} }
#ifdef CONFIG_64BIT #ifdef CONFIG_64BIT
static inline bool vma_is_sealed(struct vm_area_struct *vma) static inline bool vma_is_sealed(struct vm_area_struct *vma)
{ {
return (vma->vm_flags & VM_SEALED); return (vma->vm_flags & VM_SEALED);
} }
/*
* check if a vma is sealed for modification.
* return true, if modification is allowed.
*/
static inline bool can_modify_vma(struct vm_area_struct *vma)
{
if (unlikely(vma_is_sealed(vma)))
return false;
return true;
}
#else #else
static inline bool vma_is_sealed(struct vm_area_struct *vma)
static inline bool can_modify_vma(struct vm_area_struct *vma)
{ {
return true; return false;
} }
#endif #endif
#if defined(CONFIG_STACK_GROWSUP) #if defined(CONFIG_STACK_GROWSUP)