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| author | Gabriel Krisman Bertazi <krisman@collabora.com> | 2021-10-25 16:27:40 -0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2021-10-27 12:37:20 +0200 |
| commit | 572c28f27a269f88e2d8d7b6b1507f114d637337 (patch) | |
| tree | 83358931f5b2eb71f928daa2f4ebb582197a9168 /fs/notify | |
| parent | 4bd5a5c8e6e5cd964e9738e6ef87f6c2cb453edf (diff) | |
| download | lwn-572c28f27a269f88e2d8d7b6b1507f114d637337.tar.gz lwn-572c28f27a269f88e2d8d7b6b1507f114d637337.zip | |
fanotify: WARN_ON against too large file handles
struct fanotify_error_event, at least, is preallocated and isn't able to
to handle arbitrarily large file handles. Future-proof the code by
complaining loudly if a handle larger than MAX_HANDLE_SZ is ever found.
Link: https://lore.kernel.org/r/20211025192746.66445-26-krisman@collabora.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify')
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index cedcb1546804..45df610debbe 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -360,13 +360,23 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, static int fanotify_encode_fh_len(struct inode *inode) { int dwords = 0; + int fh_len; if (!inode) return 0; exportfs_encode_inode_fh(inode, NULL, &dwords, NULL); + fh_len = dwords << 2; - return dwords << 2; + /* + * struct fanotify_error_event might be preallocated and is + * limited to MAX_HANDLE_SZ. This should never happen, but + * safeguard by forcing an invalid file handle. + */ + if (WARN_ON_ONCE(fh_len > MAX_HANDLE_SZ)) + return 0; + + return fh_len; } /* |