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authorGabriel Krisman Bertazi <krisman@collabora.com>2021-10-25 22:27:40 +0300
committerJan Kara <jack@suse.cz>2021-10-27 13:37:20 +0300
commit572c28f27a269f88e2d8d7b6b1507f114d637337 (patch)
tree83358931f5b2eb71f928daa2f4ebb582197a9168 /fs/notify
parent4bd5a5c8e6e5cd964e9738e6ef87f6c2cb453edf (diff)
downloadlinux-572c28f27a269f88e2d8d7b6b1507f114d637337.tar.xz
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.c12
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;
}
/*