[ Upstream commit 522249f05c5551aec9ec0ba9b6438f1ec19c138d ] When working in "fd mode", fanotify_read() needs to open an fd from a dentry to report event->fd to userspace. Opening an fd from dentry can fail for several reasons. For example, when tasks are gone and we try to open their /proc files or we try to open a WRONLY file like in sysfs or when trying to open a file that was deleted on the remote network server. Add a new flag FAN_REPORT_FD_ERROR for fanotify_init(). For a group with FAN_REPORT_FD_ERROR, we will send the event with the error instead of the open fd, otherwise userspace may not get the error at all. For an overflow event, we report -EBADF to avoid confusing FAN_NOFD with -EPERM. Similarly for pidfd open errors we report either -ESRCH or the open error instead of FAN_NOPIDFD and FAN_EPIDFD. In any case, userspace will not know which file failed to open, so add a debug print for further investigation. Reported-by: Krishna Vivek Vitta <kvitta@microsoft.com> Link: https://lore.kernel.org/linux-fsdevel/SI2P153MB07182F3424619EDDD1F393EED46D2@SI2P153MB0718.APCP153.PROD.OUTLOOK.COM/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20241003142922.111539-1-amir73il@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
Several file system notification system headers have "writable" misspelled as "writtable" in the comments. This patch fixes it in the fanotify header. Signed-off-by: Vicki Pfau <vi@endrift.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20240306020831.1404033-3-vi@endrift.com>
This patch adds a flag, FAN_INFO and an extensible buffer to provide additional information about response decisions. The buffer contains one or more headers defining the information type and the length of the following information. The patch defines one additional information type, FAN_RESPONSE_INFO_AUDIT_RULE, to audit a rule number. This will allow for the creation of other information types in the future if other users of the API identify different needs. The kernel can be tested if it supports a given info type by supplying the complete info extension but setting fd to FAN_NOFD. It will return the expected size but not issue an audit record. Suggested-by: Steve Grubb <sgrubb@redhat.com> Link: https://lore.kernel.org/r/2745105.e9J7NaK4W3@x2 Suggested-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20201001101219.GE17860@quack2.suse.cz Tested-by: Steve Grubb <sgrubb@redhat.com> Acked-by: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <10177cfcae5480926b7176321a28d9da6835b667.1675373475.git.rgb@redhat.com>
Pull uapi flexible array update from Gustavo Silva:
"A treewide patch that replaces zero-length arrays with flexible-array
members in UAPI. This has been baking in linux-next for 5 weeks now.
'-fstrict-flex-arrays=3' is coming and we need to land these changes
to prevent issues like these in the short future:
fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0, but the source string has length 2 (including NUL byte) [-Wfortify-source]
strcpy(de3->name, ".");
^
Since these are all [0] to [] changes, the risk to UAPI is nearly
zero. If this breaks anything, we can use a union with a new member
name"
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836
* tag 'flexible-array-transformations-UAPI-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
treewide: uapi: Replace zero-length arrays with flexible-array members
This flag is a new way to configure ignore mask which allows adding and removing the event flags FAN_ONDIR and FAN_EVENT_ON_CHILD in ignore mask. The legacy FAN_MARK_IGNORED_MASK flag would always ignore events on directories and would ignore events on children depending on whether the FAN_EVENT_ON_CHILD flag was set in the (non ignored) mask. FAN_MARK_IGNORE can be used to ignore events on children without setting FAN_EVENT_ON_CHILD in the mark's mask and will not ignore events on directories unconditionally, only when FAN_ONDIR is set in ignore mask. The new behavior is non-downgradable. After calling fanotify_mark() with FAN_MARK_IGNORE once, calling fanotify_mark() with FAN_MARK_IGNORED_MASK on the same object will return EEXIST error. Setting the event flags with FAN_MARK_IGNORE on a non-dir inode mark has no meaning and will return ENOTDIR error. The meaning of FAN_MARK_IGNORED_SURV_MODIFY is preserved with the new FAN_MARK_IGNORE flag, but with a few semantic differences: 1. FAN_MARK_IGNORED_SURV_MODIFY is required for filesystem and mount marks and on an inode mark on a directory. Omitting this flag will return EINVAL or EISDIR error. 2. An ignore mask on a non-directory inode that survives modify could never be downgraded to an ignore mask that does not survive modify. With new FAN_MARK_IGNORE semantics we make that rule explicit - trying to update a surviving ignore mask without the flag FAN_MARK_IGNORED_SURV_MODIFY will return EEXIST error. The conveniene macro FAN_MARK_IGNORE_SURV is added for (FAN_MARK_IGNORE | FAN_MARK_IGNORED_SURV_MODIFY), because the common case should use short constant names. Link: https://lore.kernel.org/r/20220629144210.2983229-4-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].
This code was transformed with the help of Coccinelle:
(linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)
@@
identifier S, member, array;
type T1, T2;
@@
struct S {
...
T1 member;
T2 array[
- 0
];
};
-fstrict-flex-arrays=3 is coming and we need to land these changes
to prevent issues like these in the short future:
../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0,
but the source string has length 2 (including NUL byte) [-Wfortify-source]
strcpy(de3->name, ".");
^
Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If
this breaks anything, we can use a union with a new member name.
[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
Link: https://github.com/KSPP/linux/issues/78
Build-tested-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/
Acked-by: Dan Williams <dan.j.williams@intel.com> # For ndctl.h
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
When an inode mark is created with flag FAN_MARK_EVICTABLE, it will not pin the marked inode to inode cache, so when inode is evicted from cache due to memory pressure, the mark will be lost. When an inode mark with flag FAN_MARK_EVICATBLE is updated without using this flag, the marked inode is pinned to inode cache. When an inode mark is updated with flag FAN_MARK_EVICTABLE but an existing mark already has the inode pinned, the mark update fails with error EEXIST. Evictable inode marks can be used to setup inode marks with ignored mask to suppress events from uninteresting files or directories in a lazy manner, upon receiving the first event, without having to iterate all the uninteresting files or directories before hand. The evictbale inode mark feature allows performing this lazy marks setup without exhausting the system memory with pinned inodes. This change does not enable the feature yet. Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxiRDpuS=2uA6+ZUM7yG9vVU-u212tkunBmSnP_u=mkv=Q@mail.gmail.com/ Link: https://lore.kernel.org/r/20220422120327.3459282-15-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
In the special case of FAN_RENAME event, we report old or new or both
old and new parent+name.
A single info record will be reported if either the old or new dir
is watched and two records will be reported if both old and new dir
(or their filesystem) are watched.
The old and new parent+name are reported using new info record types
FAN_EVENT_INFO_TYPE_{OLD,NEW}_DFID_NAME, so if a single info record
is reported, it is clear to the application, to which dir entry the
fid+name info is referring to.
Link: https://lore.kernel.org/r/20211129201537.1932819-11-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
In the special case of FAN_RENAME event, we record both the old and new parent and name. Link: https://lore.kernel.org/r/20211129201537.1932819-9-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
FAN_REPORT_FID is ambiguous in that it reports the fid of the child for some events and the fid of the parent for create/delete/move events. The new FAN_REPORT_TARGET_FID flag is an implicit request to report the fid of the target object of the operation (a.k.a the child inode) also in create/delete/move events in addition to the fid of the parent and the name of the child. To reduce the test matrix for uninteresting use cases, the new FAN_REPORT_TARGET_FID flag requires both FAN_REPORT_NAME and FAN_REPORT_FID. The convenience macro FAN_REPORT_DFID_NAME_TARGET combines FAN_REPORT_TARGET_FID with all the required flags. Link: https://lore.kernel.org/r/20211129201537.1932819-4-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>