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authorXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>2020-05-05 11:28:53 +0300
committerJens Axboe <axboe@kernel.dk>2020-05-05 22:18:11 +0300
commit7f13657d141346125f4d0bb93eab4777f40c406e (patch)
treeee786539b1ab574f47c0f9dd9c406a36176cc6c8 /fs
parentd8f1b9716cfd1a1f74c0fedad40c5f65a25aa208 (diff)
downloadlinux-7f13657d141346125f4d0bb93eab4777f40c406e.tar.xz
io_uring: handle -EFAULT properly in io_uring_setup()
If copy_to_user() in io_uring_setup() failed, we'll leak many kernel resources, which will be recycled until process terminates. This bug can be reproduced by using mprotect to set params to PROT_READ. To fix this issue, refactor io_uring_create() a bit to add a new 'struct io_uring_params __user *params' parameter and move the copy_to_user() in io_uring_setup() to io_uring_setup(), if copy_to_user() failed, we can free kernel resource properly. Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c24
1 files changed, 11 insertions, 13 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6d52ff98279d..dd680eb153cb 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7760,7 +7760,8 @@ err:
return ret;
}
-static int io_uring_create(unsigned entries, struct io_uring_params *p)
+static int io_uring_create(unsigned entries, struct io_uring_params *p,
+ struct io_uring_params __user *params)
{
struct user_struct *user = NULL;
struct io_ring_ctx *ctx;
@@ -7852,6 +7853,14 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
p->cq_off.cqes = offsetof(struct io_rings, cqes);
+ p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
+ IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
+ IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL;
+
+ if (copy_to_user(params, p, sizeof(*p))) {
+ ret = -EFAULT;
+ goto err;
+ }
/*
* Install ring fd as the very last thing, so we don't risk someone
* having closed it before we finish setup
@@ -7860,9 +7869,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
if (ret < 0)
goto err;
- p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
- IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
- IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL;
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
return ret;
err:
@@ -7878,7 +7884,6 @@ err:
static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
{
struct io_uring_params p;
- long ret;
int i;
if (copy_from_user(&p, params, sizeof(p)))
@@ -7893,14 +7898,7 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ))
return -EINVAL;
- ret = io_uring_create(entries, &p);
- if (ret < 0)
- return ret;
-
- if (copy_to_user(params, &p, sizeof(p)))
- return -EFAULT;
-
- return ret;
+ return io_uring_create(entries, &p, params);
}
SYSCALL_DEFINE2(io_uring_setup, u32, entries,