From c59a37701bf49dbcba2297e7507d62ee05d9c916 Mon Sep 17 00:00:00 2001 From: Dave Reisner Date: Sat, 26 Apr 2014 14:06:06 -0400 Subject: implement a union to pad out file_handle Cases where name_to_handle_at is used allocated the full struct to be MAX_HANDLE_SZ, and assigned this size to handle_bytes. This is wrong since handle_bytes should describe the length of the flexible array member and not the whole struct. Define a union type which includes sufficient padding to allow assignment of MAX_HANDLE_SZ to be correct. Signed-off-by: Anthony G. Basile --- src/libudev/libudev-monitor.c | 6 ++---- src/libudev/util.h | 6 ++++++ 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/src/libudev/libudev-monitor.c b/src/libudev/libudev-monitor.c index 43fd8762da..ec3f6da91e 100644 --- a/src/libudev/libudev-monitor.c +++ b/src/libudev/libudev-monitor.c @@ -108,15 +108,13 @@ static struct udev_monitor *udev_monitor_new(struct udev *udev) /* we consider udev running when /dev is on devtmpfs */ static bool udev_has_devtmpfs(struct udev *udev) { - struct file_handle *h; + union file_handle_union h = { .handle.handle_bytes = MAX_HANDLE_SZ, }; int mount_id; _cleanup_fclose_ FILE *f = NULL; char line[LINE_MAX], *e; int r; - h = alloca(MAX_HANDLE_SZ); - h->handle_bytes = MAX_HANDLE_SZ; - r = name_to_handle_at(AT_FDCWD, "/dev", h, &mount_id, 0); + r = name_to_handle_at(AT_FDCWD, "/dev", &h.handle, &mount_id, 0); if (r < 0) return false; diff --git a/src/libudev/util.h b/src/libudev/util.h index 6510237e1e..4efa4e062a 100644 --- a/src/libudev/util.h +++ b/src/libudev/util.h @@ -19,6 +19,7 @@ #pragma once +#include #include #include #include @@ -300,3 +301,8 @@ static inline void qsort_safe(void *base, size_t nmemb, size_t size, int proc_cmdline(char **ret); int getpeercred(int fd, struct ucred *ucred); + +union file_handle_union { + struct file_handle handle; + char padding[sizeof(struct file_handle) + MAX_HANDLE_SZ]; +}; -- cgit v1.2.3-54-g00ecf