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| author | Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> | 2020-05-05 16:28:53 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-05-05 13:18:11 -0600 |
| commit | 7f13657d141346125f4d0bb93eab4777f40c406e (patch) | |
| tree | ee786539b1ab574f47c0f9dd9c406a36176cc6c8 /fs/io_uring.c | |
| parent | d8f1b9716cfd1a1f74c0fedad40c5f65a25aa208 (diff) | |
| download | linux-7f13657d141346125f4d0bb93eab4777f40c406e.tar.gz | |
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/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 24 |
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, |