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Re: [Qemu-devel] [PATCH] qemu-pr-helper: check the return value of fcntl
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] qemu-pr-helper: check the return value of fcntl in do_pr_out |
Date: |
Thu, 21 Mar 2019 11:37:45 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 |
On 20/03/19 15:07, Zhengui li wrote:
> The function fcntl maybe return -1, which is not a unsigned type.
> Unsigned type or Negative values should not do bitwise operator with
> O_ACCMODE.
Did you actually find a case in which the fcntl can fail?
Paolo
> Signed-off-by: Zhengui li <address@hidden>
> ---
> scsi/qemu-pr-helper.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
> index e7af637..fcbe4d9 100644
> --- a/scsi/qemu-pr-helper.c
> +++ b/scsi/qemu-pr-helper.c
> @@ -551,8 +551,14 @@ static int do_pr_out(int fd, const uint8_t *cdb, uint8_t
> *sense,
> const uint8_t *param, int sz)
> {
> int resp_sz;
> + int flags;
>
> - if ((fcntl(fd, F_GETFL) & O_ACCMODE) == O_RDONLY) {
> + flags = fcntl(fd, F_GETFL);
> + if (flags < 0) {
> + return -1;
> + }
> +
> + if (((unsigned int) flags & O_ACCMODE) == O_RDONLY) {
> scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
> return CHECK_CONDITION;
> }
>