Re: [PATCH v7 14/28] fanotify: Encode empty file handle when no inode is provided
From: Amir Goldstein <amir73il@gmail.com>
Date: 2021-10-15 06:03:01
Also in:
linux-api, linux-fsdevel
On Fri, Oct 15, 2021 at 12:38 AM Gabriel Krisman Bertazi [off-list ref] wrote:
Instead of failing, encode an invalid file handle in fanotify_encode_fh if no inode is provided. This bogus file handle will be reported by FAN_FS_ERROR for non-inode errors. Signed-off-by: Gabriel Krisman Bertazi <redacted>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
quoted hunk ↗ jump to hunk
--- Changes since v6: - Use FILEID_ROOT as the internal value (jan) - Create an empty FH (jan) Changes since v5: - Preserve flags initialization (jan) - Add BUILD_BUG_ON (amir) - Require minimum of FANOTIFY_NULL_FH_LEN for fh_len(amir) - Improve comment to explain the null FH length (jan) - Simplify logic --- fs/notify/fanotify/fanotify.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index ec84fee7ad01..c64d61b673ca 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c@@ -370,8 +370,14 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, fh->type = FILEID_ROOT; fh->len = 0; fh->flags = 0; + + /* + * Invalid FHs are used by FAN_FS_ERROR for errors not + * linked to any inode. The f_handle won't be reported + * back to userspace. + */ if (!inode) - return 0; + goto out; /* * !gpf means preallocated variable size fh, but fh_len could@@ -403,6 +409,7 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, fh->type = type; fh->len = fh_len; +out: /* * Mix fh into event merge key. Hash might be NULL in case of * unhashed FID events (i.e. FAN_FS_ERROR). --2.33.0