5.10-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
[ Upstream commit 8698e3bab4dd7968666e84e111d0bfd17c040e77 ]
Commit ceaf69f8eadc ("fanotify: do not allow setting dirent events in mask of non-dir") added restrictions about setting dirent events in the mask of a non-dir inode mark, which does not make any sense.
For backward compatibility, these restictions were added only to new (v5.17+) APIs.
It also does not make any sense to set the flags FAN_EVENT_ON_CHILD or FAN_ONDIR in the mask of a non-dir inode. Add these flags to the dir-only restriction of the new APIs as well.
Move the check of the dir-only flags for new APIs into the helper fanotify_events_supported(), which is only called for FAN_MARK_ADD, because there is no need to error on an attempt to remove the dir-only flags from non-dir inode.
Fixes: ceaf69f8eadc ("fanotify: do not allow setting dirent events in mask of non-dir") Link: https://lore.kernel.org/linux-fsdevel/20220627113224.kr2725conevh53u4@quack3... Link: https://lore.kernel.org/r/20220627174719.2838175-1-amir73il@gmail.com Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Jan Kara jack@suse.cz [ cel: adjusted to apply to v5.10.y ] Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/notify/fanotify/fanotify_user.c | 30 +++++++++++++++--------------- include/linux/fanotify.h | 4 ++++ 2 files changed, 19 insertions(+), 15 deletions(-)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index f4a5e9074dd42..990464e00aec7 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1501,10 +1501,14 @@ static int fanotify_test_fid(struct dentry *dentry) return 0; }
-static int fanotify_events_supported(struct path *path, __u64 mask, +static int fanotify_events_supported(struct fsnotify_group *group, + struct path *path, __u64 mask, unsigned int flags) { unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS; + /* Strict validation of events in non-dir inode mask with v5.17+ APIs */ + bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) || + (mask & FAN_RENAME);
/* * Some filesystems such as 'proc' acquire unusual locks when opening @@ -1532,6 +1536,15 @@ static int fanotify_events_supported(struct path *path, __u64 mask, path->mnt->mnt_sb->s_flags & SB_NOUSER) return -EINVAL;
+ /* + * We shouldn't have allowed setting dirent events and the directory + * flags FAN_ONDIR and FAN_EVENT_ON_CHILD in mask of non-dir inode, + * but because we always allowed it, error only when using new APIs. + */ + if (strict_dir_events && mark_type == FAN_MARK_INODE && + !d_is_dir(path->dentry) && (mask & FANOTIFY_DIRONLY_EVENT_BITS)) + return -ENOTDIR; + return 0; }
@@ -1678,7 +1691,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, goto fput_and_out;
if (flags & FAN_MARK_ADD) { - ret = fanotify_events_supported(&path, mask, flags); + ret = fanotify_events_supported(group, &path, mask, flags); if (ret) goto path_put_and_out; } @@ -1701,19 +1714,6 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, else mnt = path.mnt;
- /* - * FAN_RENAME is not allowed on non-dir (for now). - * We shouldn't have allowed setting any dirent events in mask of - * non-dir, but because we always allowed it, error only if group - * was initialized with the new flag FAN_REPORT_TARGET_FID. - */ - ret = -ENOTDIR; - if (inode && !S_ISDIR(inode->i_mode) && - ((mask & FAN_RENAME) || - ((mask & FANOTIFY_DIRENT_EVENTS) && - FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID)))) - goto path_put_and_out; - /* Mask out FAN_EVENT_ON_CHILD flag for sb/mount/non-dir marks */ if (mnt || !S_ISDIR(inode->i_mode)) { mask &= ~FAN_EVENT_ON_CHILD; diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index 81f45061c1b18..4f6cbe6c6e235 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -113,6 +113,10 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */ FANOTIFY_PERM_EVENTS | \ FAN_Q_OVERFLOW | FAN_ONDIR)
+/* Events and flags relevant only for directories */ +#define FANOTIFY_DIRONLY_EVENT_BITS (FANOTIFY_DIRENT_EVENTS | \ + FAN_EVENT_ON_CHILD | FAN_ONDIR) + #define ALL_FANOTIFY_EVENT_BITS (FANOTIFY_OUTGOING_EVENTS | \ FANOTIFY_EVENT_FLAGS)