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: ff4afde8a61f ("io_uring/kbuf: use region api for pbuf rings")
Signed-off-by: Colin Ian King <colin.i.king@xxxxxxxxx>
---
io_uring/kbuf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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));
--
2.39.5
