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SubjectRe: [PATCH 1/5] ima: Set file->f_mode instead of file->f_flags in ima_calc_file_hash()
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[CC'ing Goldwyn Rodrigues]

Hi Roberto,

On Wed, 2020-03-25 at 17:11 +0100, Roberto Sassu wrote:
> Commit a408e4a86b36 ("ima: open a new file instance if no read
> permissions") tries to create a new file descriptor to calculate a file
> digest if the file has not been opened with O_RDONLY flag. However, if a
> new file descriptor cannot be obtained, it sets the FMODE_READ flag to
> file->f_flags instead of file->f_mode.
>
> This patch fixes this issue by replacing f_flags with f_mode as it was
> before that commit.
>
> Cc: stable@vger.kernel.org # 4.20.x
> Fixes: a408e4a86b36 ("ima: open a new file instance if no read permissions")
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
> security/integrity/ima/ima_crypto.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
> index 423c84f95a14..8ab17aa867dd 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -436,7 +436,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
> */

Thanks, Roberto.  The comment above here and the rest of the code
refers to flags.  Both should be updated as well to reflect using
f_mode.

> pr_info_ratelimited("Unable to reopen file for reading.\n");
> f = file;
> - f->f_flags |= FMODE_READ;
> + f->f_mode |= FMODE_READ;
> modified_flags = true;

The variable should be changed to "modified_mode".

thanks,

Mimi

> } else {
> new_file_instance = true;
> @@ -456,7 +456,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
> if (new_file_instance)
> fput(f);
> else if (modified_flags)
> - f->f_flags &= ~FMODE_READ;
> + f->f_mode &= ~FMODE_READ;
> return rc;
> }
>

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