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fs/ntfs3: resize log->one_page_buf when adopting on-disk page size

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log_replay() allocates log->one_page_buf using the page size that was
chosen from the host PAGE_SIZE:

	log->one_page_buf = kmalloc(log->page_size, GFP_NOFS);

Later, when a restart area is found, the log page size recorded on disk
is adopted:

	t32 = le32_to_cpu(log->rst_info.r_page->sys_page_size);
	if (log->page_size != t32) {
		log->l_size = log->orig_file_size;
		log->page_size = norm_file_page(t32, &log->l_size,
						t32 == DefaultLogPageSize);
	}

If the on-disk page size is larger than the size used for the initial
allocation, log->page_size grows but one_page_buf is left at its
original, smaller size. A subsequent unaligned read_log_page() then
reads log->page_size bytes into the undersized scratch buffer:

	page_buf = page_off ? log->one_page_buf : *buffer;
	err = ntfs_read_run_nb_ra(ni->mi.sbi, &ni->file.run, page_vbo, page_buf,
				  log->page_size, NULL, &log->read_ahead);

overflowing the allocation. This is reachable when mounting a dirty
NTFS volume whose log was formatted with a page size larger than the
buffer initially allocated on the mounting host (for example a 64K-log
volume mounted on a host that allocated a 4K scratch buffer).

Grow one_page_buf when the adopted on-disk page size exceeds the size
used for the initial allocation. On krealloc() failure the original
buffer is left intact and freed by the existing error path.

Fixes: b46acd6a6a ("fs/ntfs3: Add NTFS journal")
Reported-by: Carol L Soto <csoto@nvidia.com>
Signed-off-by: Jamie Nguyen <jamien@nvidia.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
This commit is contained in:
Jamie Nguyen
2026-06-04 21:19:30 -07:00
committed by Konstantin Komarov
parent 57ac2831c8
commit 5a35454179
1 changed files with 19 additions and 0 deletions
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19
fs/ntfs3/fslog.c
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@@ -4005,9 +4005,28 @@ int log_replay(struct ntfs_inode *ni, bool *initialized)
*/
t32 = le32_to_cpu(log->rst_info.r_page->sys_page_size);
if (log->page_size != t32) {
u32 old_page_size = log->page_size;
log->l_size = log->orig_file_size;
log->page_size = norm_file_page(t32, &log->l_size,
t32 == DefaultLogPageSize);
/*
* If the adopted on-disk page size is larger than the size used
* to allocate one_page_buf above, grow the scratch buffer so a
* later read_log_page() cannot overflow it.
*/
if (log->page_size > old_page_size) {
void *buf;
buf = krealloc(log->one_page_buf, log->page_size,
GFP_NOFS);
if (!buf) {
err = -ENOMEM;
goto out;
}
log->one_page_buf = buf;
}
}
if (log->page_size != t32 ||