5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Amir Goldstein <amir73il@xxxxxxxxx> [ Upstream commit 1a9515ac9e55e68d733bab81bd408463ab1e25b1 ] fanotify_info buffer is parceled into variable sized records, so the records must be written in order: dir_fh, file_fh, name. Use helpers to assert that order and make fanotify_alloc_name_event() a bit more generic to allow empty dir_fh record and to allow expanding to more records (i.e. name2) soon. Link: https://lore.kernel.org/r/20211129201537.1932819-7-amir73il@xxxxxxxxx Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> Signed-off-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- fs/notify/fanotify/fanotify.c | 35 +++++++++++++++++++---------------- fs/notify/fanotify/fanotify.h | 20 ++++++++++++++++++++ 2 files changed, 39 insertions(+), 16 deletions(-) diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index ffad224be0149..2b13c79cebc62 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -576,7 +576,7 @@ static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id, return &ffe->fae; } -static struct fanotify_event *fanotify_alloc_name_event(struct inode *id, +static struct fanotify_event *fanotify_alloc_name_event(struct inode *dir, __kernel_fsid_t *fsid, const struct qstr *name, struct inode *child, @@ -586,15 +586,17 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id, struct fanotify_name_event *fne; struct fanotify_info *info; struct fanotify_fh *dfh, *ffh; - unsigned int dir_fh_len = fanotify_encode_fh_len(id); + unsigned int dir_fh_len = fanotify_encode_fh_len(dir); unsigned int child_fh_len = fanotify_encode_fh_len(child); - unsigned int size; + unsigned long name_len = name ? name->len : 0; + unsigned int len, size; - size = sizeof(*fne) + FANOTIFY_FH_HDR_LEN + dir_fh_len; + /* Reserve terminating null byte even for empty name */ + size = sizeof(*fne) + name_len + 1; + if (dir_fh_len) + size += FANOTIFY_FH_HDR_LEN + dir_fh_len; if (child_fh_len) size += FANOTIFY_FH_HDR_LEN + child_fh_len; - if (name) - size += name->len + 1; fne = kmalloc(size, gfp); if (!fne) return NULL; @@ -604,22 +606,23 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id, *hash ^= fanotify_hash_fsid(fsid); info = &fne->info; fanotify_info_init(info); - dfh = fanotify_info_dir_fh(info); - info->dir_fh_totlen = fanotify_encode_fh(dfh, id, dir_fh_len, hash, 0); + if (dir_fh_len) { + dfh = fanotify_info_dir_fh(info); + len = fanotify_encode_fh(dfh, dir, dir_fh_len, hash, 0); + fanotify_info_set_dir_fh(info, len); + } if (child_fh_len) { ffh = fanotify_info_file_fh(info); - info->file_fh_totlen = fanotify_encode_fh(ffh, child, - child_fh_len, hash, 0); + len = fanotify_encode_fh(ffh, child, child_fh_len, hash, 0); + fanotify_info_set_file_fh(info, len); } - if (name) { - long salt = name->len; - + if (name_len) { fanotify_info_copy_name(info, name); - *hash ^= full_name_hash((void *)salt, name->name, name->len); + *hash ^= full_name_hash((void *)name_len, name->name, name_len); } - pr_debug("%s: ino=%lu size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n", - __func__, id->i_ino, size, dir_fh_len, child_fh_len, + pr_debug("%s: size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n", + __func__, size, dir_fh_len, child_fh_len, info->name_len, info->name_len, fanotify_info_name(info)); return &fne->fae; diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h index dd23ba659e76b..7ac6f9f1e4148 100644 --- a/fs/notify/fanotify/fanotify.h +++ b/fs/notify/fanotify/fanotify.h @@ -138,6 +138,26 @@ static inline void fanotify_info_init(struct fanotify_info *info) info->name_len = 0; } +/* These set/copy helpers MUST be called by order */ +static inline void fanotify_info_set_dir_fh(struct fanotify_info *info, + unsigned int totlen) +{ + if (WARN_ON_ONCE(info->file_fh_totlen > 0) || + WARN_ON_ONCE(info->name_len > 0)) + return; + + info->dir_fh_totlen = totlen; +} + +static inline void fanotify_info_set_file_fh(struct fanotify_info *info, + unsigned int totlen) +{ + if (WARN_ON_ONCE(info->name_len > 0)) + return; + + info->file_fh_totlen = totlen; +} + static inline void fanotify_info_copy_name(struct fanotify_info *info, const struct qstr *name) { -- 2.43.0
