Friendly ping :-)
On 7/2/21 1:31 AM, David Oberhollenzer wrote:
> For obvious security reasons, a core dump is aborted if the
> filesystem cannot preserve ownership or permissions of the
> dump file.
>
> This affects filesystems like e.g. vfat, but also something like
> a 9pfs share in a Qemu test setup, running as a regular user,
> depending on the security model used. In those cases, the result
> is an empty core file and a confused user.
>
> To hopefully safe other people a lot of time figuring out the
> cause, this patch adds a simple log message for those specific
> cases.
>
> Signed-off-by: David Oberhollenzer <david.oberhollenzer@xxxxxxxxxxxxx>
> ---
> fs/coredump.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/fs/coredump.c b/fs/coredump.c
> index c3d8fc14b993..3e53d3e18b0e 100644
> --- a/fs/coredump.c
> +++ b/fs/coredump.c
> @@ -782,10 +777,17 @@ void do_coredump(const kernel_siginfo_t *siginfo)
> * filesystem.
> */
> mnt_userns = file_mnt_user_ns(cprm.file);
> - if (!uid_eq(i_uid_into_mnt(mnt_userns, inode), current_fsuid()))
> + if (!uid_eq(i_uid_into_mnt(mnt_userns, inode),
> + current_fsuid())) {
> + pr_info_ratelimited("Core dump to |%s aborted: cannot preserve file owner\n",
> + cn.corename);
> goto close_fail;
> - if ((inode->i_mode & 0677) != 0600)
> + }
> + if ((inode->i_mode & 0677) != 0600) {
> + pr_info_ratelimited("Core dump to |%s aborted: cannot preserve file permissions\n",
> + cn.corename);
> goto close_fail;
> + }
> if (!(cprm.file->f_mode & FMODE_CAN_WRITE))
> goto close_fail;
> if (do_truncate(mnt_userns, cprm.file->f_path.dentry,
> --
> 2.31.1
>
