[PATCH AUTOSEL 5.6 082/606] ima: Set file->f_mode instead of file->f_flags in ima_calc_file_hash()

Sasha Levin
2020-06-08T23:16:43Z

From: Roberto Sassu <roberto.sassu@huawei.com>

[ Upstream commit 0014cc04e8ec077dc482f00c87dfd949cfe2b98f ]

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>
Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/integrity/ima/ima_crypto.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 7967a6904851..e8fa23cd4a6c 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -413,7 +413,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
loff_t i_size;
int rc;
struct file *f = file;
- bool new_file_instance = false, modified_flags = false;
+ bool new_file_instance = false, modified_mode = false;

/*
* For consistency, fail file's opened with the O_DIRECT flag on
@@ -433,13 +433,13 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
f = dentry_open(&file->f_path, flags, file->f_cred);
if (IS_ERR(f)) {
/*
- * Cannot open the file again, lets modify f_flags
+ * Cannot open the file again, lets modify f_mode
* of original and continue
*/
pr_info_ratelimited("Unable to reopen file for reading.\n");
f = file;
- f->f_flags |= FMODE_READ;
- modified_flags = true;
+ f->f_mode |= FMODE_READ;
+ modified_mode = true;
} else {
new_file_instance = true;
}
@@ -457,8 +457,8 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
out:
if (new_file_instance)
fput(f);
- else if (modified_flags)
- f->f_flags &= ~FMODE_READ;
+ else if (modified_mode)
+ f->f_mode &= ~FMODE_READ;
return rc;
}

--
2.25.1