diff options
| author | Colin Ian King <colin.i.king@gmail.com> | 2024-12-04 15:39:23 +0000 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-12-23 08:20:00 -0700 |
| commit | febfbf767174b8a027efb7aa434f9a9416adc23d (patch) | |
| tree | 5009edfe5ba35faee86f6c4ed1814bb9bd96c059 /io_uring/kbuf.c | |
| parent | 546d191427cf5cf3215529744c2ea8558f0279db (diff) | |
io_uring/kbuf: fix unintentional sign extension on shift of reg.bgid
Shifting reg.bgid << IORING_OFF_PBUF_SHIFT results in a promotion
from __u16 to a 32 bit signed integer, this is then sign extended
to a 64 bit unsigned long on 64 bit architectures. If reg.bgid is
greater than 0x7fff then this leads to a sign extended result where
all the upper 32 bits of mmap_offset are set to 1. Fix this by
casting reg.bgid to the same type as mmap_offset before performing
the shift.
Fixes: ef62de3c4ad5 ("io_uring/kbuf: use region api for pbuf rings")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20241204153923.401674-1-colin.i.king@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/kbuf.c')
| -rw-r--r-- | io_uring/kbuf.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index e91260a6156b..15e5e6ec5968 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -640,7 +640,7 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) return -ENOMEM; } - mmap_offset = reg.bgid << IORING_OFF_PBUF_SHIFT; + mmap_offset = (unsigned long)reg.bgid << IORING_OFF_PBUF_SHIFT; ring_size = flex_array_size(br, bufs, reg.ring_entries); memset(&rd, 0, sizeof(rd)); |