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| author | Deepanshu Kartikey <kartikey406@gmail.com> | 2026-06-21 06:59:33 +0530 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-06-22 15:12:54 -0600 |
| commit | 3996771b8f759729cba0a28007438c085f814d61 (patch) | |
| tree | cf26db7be6e9fe4f1f3c4d30c4ad9ed1262a4d13 /io_uring | |
| parent | ff3ac1a0bd75400375678c0f81c2b613cbc03e14 (diff) | |
| download | linux-next-3996771b8f759729cba0a28007438c085f814d61.tar.gz linux-next-3996771b8f759729cba0a28007438c085f814d61.zip | |
io_uring/memmap: bound io_pin_pages() by page array byte size
io_pin_pages() checks that nr_pages does not exceed INT_MAX, then
allocates a struct page * array of nr_pages entries. kvmalloc() limits
allocations to INT_MAX bytes, but the check counts pages, not bytes.
On 64-bit each entry is 8 bytes, so the array hits the INT_MAX byte
limit at INT_MAX / sizeof(struct page *) pages, well before the page
count check fires.
Since commit b4e41050b212 ("io_uring/rsrc: raise registered buffer 1GB
limit") raised the per-buffer cap to 1TB, a buffer near that cap maps
~2^28 pages, making the array allocation exceed INT_MAX bytes. This
passes the page count check, reaches kvmalloc(), and triggers the
WARN_ON_ONCE() for oversized allocations in __kvmalloc_node_noprof().
Check nr_pages against INT_MAX / sizeof(struct page *) so the buffer is
rejected with -EOVERFLOW before the allocation is attempted.
Reported-by: syzbot+f99b00a963915b6b52c6@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f99b00a963915b6b52c6
Fixes: b4e41050b212 ("io_uring/rsrc: raise registered buffer 1GB limit")
Tested-by: syzbot+f99b00a963915b6b52c6@syzkaller.appspotmail.com
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://patch.msgid.link/20260621012933.50571-1-kartikey406@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/memmap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/io_uring/memmap.c b/io_uring/memmap.c index 4f9b439319c4..da1f6c5d07f8 100644 --- a/io_uring/memmap.c +++ b/io_uring/memmap.c @@ -53,7 +53,7 @@ struct page **io_pin_pages(unsigned long uaddr, unsigned long len, int *npages) nr_pages = end - start; if (WARN_ON_ONCE(!nr_pages)) return ERR_PTR(-EINVAL); - if (WARN_ON_ONCE(nr_pages > INT_MAX)) + if (nr_pages > INT_MAX / sizeof(struct page *)) return ERR_PTR(-EOVERFLOW); pages = kvmalloc_objs(struct page *, nr_pages, GFP_KERNEL_ACCOUNT); |