diff options
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 75 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify.h | 12 |
2 files changed, 59 insertions, 28 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 31fd41e91575..c107974d6830 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -299,55 +299,78 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, } /* + * Check size needed to encode fanotify_fh. + * + * Return size of encoded fh without fanotify_fh header. + * Return 0 on failure to encode. + */ +static int fanotify_encode_fh_len(struct inode *inode) +{ + int dwords = 0; + + if (!inode) + return 0; + + exportfs_encode_inode_fh(inode, NULL, &dwords, NULL); + + return dwords << 2; +} + +/* * Encode fanotify_fh. * * Return total size of encoded fh including fanotify_fh header. * Return 0 on failure to encode. */ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, - gfp_t gfp) + unsigned int fh_len, gfp_t gfp) { - int dwords, type, bytes = 0; + int dwords, type = 0; char *ext_buf = NULL; void *buf = fh->buf; int err; fh->type = FILEID_ROOT; fh->len = 0; + fh->flags = 0; if (!inode) return 0; - dwords = 0; + /* + * !gpf means preallocated variable size fh, but fh_len could + * be zero in that case if encoding fh len failed. + */ err = -ENOENT; - type = exportfs_encode_inode_fh(inode, NULL, &dwords, NULL); - if (!dwords) + if (fh_len < 4 || WARN_ON_ONCE(fh_len % 4)) goto out_err; - bytes = dwords << 2; - if (bytes > FANOTIFY_INLINE_FH_LEN) { - /* Treat failure to allocate fh as failure to allocate event */ + /* No external buffer in a variable size allocated fh */ + if (gfp && fh_len > FANOTIFY_INLINE_FH_LEN) { + /* Treat failure to allocate fh as failure to encode fh */ err = -ENOMEM; - ext_buf = kmalloc(bytes, gfp); + ext_buf = kmalloc(fh_len, gfp); if (!ext_buf) goto out_err; *fanotify_fh_ext_buf_ptr(fh) = ext_buf; buf = ext_buf; + fh->flags |= FANOTIFY_FH_FLAG_EXT_BUF; } + dwords = fh_len >> 2; type = exportfs_encode_inode_fh(inode, buf, &dwords, NULL); err = -EINVAL; - if (!type || type == FILEID_INVALID || bytes != dwords << 2) + if (!type || type == FILEID_INVALID || fh_len != dwords << 2) goto out_err; fh->type = type; - fh->len = bytes; + fh->len = fh_len; - return FANOTIFY_FH_HDR_LEN + bytes; + return FANOTIFY_FH_HDR_LEN + fh_len; out_err: pr_warn_ratelimited("fanotify: failed to encode fid (type=%d, len=%d, err=%i)\n", - type, bytes, err); + type, fh_len, err); kfree(ext_buf); *fanotify_fh_ext_buf_ptr(fh) = NULL; /* Report the event without a file identifier on encode error */ @@ -419,7 +442,8 @@ static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id, ffe->fae.type = FANOTIFY_EVENT_TYPE_FID; ffe->fsid = *fsid; - fanotify_encode_fh(&ffe->object_fh, id, gfp); + fanotify_encode_fh(&ffe->object_fh, id, fanotify_encode_fh_len(id), + gfp); return &ffe->fae; } @@ -432,8 +456,13 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id, struct fanotify_name_event *fne; struct fanotify_info *info; struct fanotify_fh *dfh; + unsigned int dir_fh_len = fanotify_encode_fh_len(id); + unsigned int size; - fne = kmalloc(sizeof(*fne) + file_name->len + 1, gfp); + size = sizeof(*fne) + FANOTIFY_FH_HDR_LEN + dir_fh_len; + if (file_name) + size += file_name->len + 1; + fne = kmalloc(size, gfp); if (!fne) return NULL; @@ -442,8 +471,13 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id, info = &fne->info; fanotify_info_init(info); dfh = fanotify_info_dir_fh(info); - info->dir_fh_totlen = fanotify_encode_fh(dfh, id, gfp); - fanotify_info_copy_name(info, file_name); + info->dir_fh_totlen = fanotify_encode_fh(dfh, id, dir_fh_len, 0); + if (file_name) + fanotify_info_copy_name(info, file_name); + + pr_debug("%s: ino=%lu size=%u dir_fh_len=%u name_len=%u name='%.*s'\n", + __func__, id->i_ino, size, dir_fh_len, + info->name_len, info->name_len, fanotify_info_name(info)); return &fne->fae; } @@ -658,12 +692,7 @@ static void fanotify_free_fid_event(struct fanotify_event *event) static void fanotify_free_name_event(struct fanotify_event *event) { - struct fanotify_name_event *fne = FANOTIFY_NE(event); - struct fanotify_fh *dfh = fanotify_info_dir_fh(&fne->info); - - if (fanotify_fh_has_ext_buf(dfh)) - kfree(fanotify_fh_ext_buf(dfh)); - kfree(fne); + kfree(FANOTIFY_NE(event)); } static void fanotify_free_event(struct fsnotify_event *fsn_event) diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h index 5e104fc56abb..12c204b1489f 100644 --- a/fs/notify/fanotify/fanotify.h +++ b/fs/notify/fanotify/fanotify.h @@ -29,8 +29,10 @@ enum { struct fanotify_fh { u8 type; u8 len; - u8 pad[2]; - unsigned char buf[FANOTIFY_INLINE_FH_LEN]; +#define FANOTIFY_FH_FLAG_EXT_BUF 1 + u8 flags; + u8 pad; + unsigned char buf[]; } __aligned(4); /* Variable size struct for dir file handle + child file handle + name */ @@ -50,7 +52,7 @@ struct fanotify_info { static inline bool fanotify_fh_has_ext_buf(struct fanotify_fh *fh) { - return fh->len > FANOTIFY_INLINE_FH_LEN; + return (fh->flags & FANOTIFY_FH_FLAG_EXT_BUF); } static inline char **fanotify_fh_ext_buf_ptr(struct fanotify_fh *fh) @@ -154,6 +156,8 @@ struct fanotify_fid_event { struct fanotify_event fae; __kernel_fsid_t fsid; struct fanotify_fh object_fh; + /* Reserve space in object_fh.buf[] - access with fanotify_fh_buf() */ + unsigned char _inline_fh_buf[FANOTIFY_INLINE_FH_LEN]; }; static inline struct fanotify_fid_event * @@ -166,8 +170,6 @@ struct fanotify_name_event { struct fanotify_event fae; __kernel_fsid_t fsid; struct fanotify_info info; - /* Reserve space in info.buf[] - access with fanotify_info_dir_fh() */ - struct fanotify_fh _dir_fh; }; static inline struct fanotify_name_event * |