diff options
| author | Carlos Llamas <cmllamas@google.com> | 2025-08-28 14:26:56 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-09-08 23:45:11 -0700 |
| commit | 78d2d32f0b789d67cbe5cfea0c0714cb2446c37e (patch) | |
| tree | 199c1ef963935d9e78f11aa6dc0bf4752930bce5 | |
| parent | 7989fdce69ec0a928e136477da2aa208a191fba2 (diff) | |
mm/mremap: fix regression in vrm->new_addr check
Commit 3215eaceca87 ("mm/mremap: refactor initial parameter sanity
checks") moved the sanity check for vrm->new_addr from mremap_to() to
check_mremap_params().
However, this caused a regression as vrm->new_addr is now checked even
when MREMAP_FIXED and MREMAP_DONTUNMAP flags are not specified. In this
case, vrm->new_addr can be garbage and create unexpected failures.
Fix this by moving the new_addr check after the vrm_implies_new_addr()
guard. This ensures that the new_addr is only checked when the user has
specified one explicitly.
Link: https://lkml.kernel.org/r/20250828142657.770502-1-cmllamas@google.com
Fixes: 3215eaceca87 ("mm/mremap: refactor initial parameter sanity checks")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/mremap.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index e618a706aff5..35de0a7b910e 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -1774,15 +1774,18 @@ static unsigned long check_mremap_params(struct vma_remap_struct *vrm) if (!vrm->new_len) return -EINVAL; - /* Is the new length or address silly? */ - if (vrm->new_len > TASK_SIZE || - vrm->new_addr > TASK_SIZE - vrm->new_len) + /* Is the new length silly? */ + if (vrm->new_len > TASK_SIZE) return -EINVAL; /* Remainder of checks are for cases with specific new_addr. */ if (!vrm_implies_new_addr(vrm)) return 0; + /* Is the new address silly? */ + if (vrm->new_addr > TASK_SIZE - vrm->new_len) + return -EINVAL; + /* The new address must be page-aligned. */ if (offset_in_page(vrm->new_addr)) return -EINVAL; |