From 15934e2c8123ee307574059d7c3f6a5916c054c9 Mon Sep 17 00:00:00 2001

From: Dave Reisner <dreisner@archlinux.org>

Date: Sat, 19 Apr 2014 13:22:35 -0400

Subject: [PATCH] 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.

(cherry picked from commit 370c860f748d149097710dc7952a64f627db9de7)

Conflicts:

	src/shared/util.h

(cherry picked from commit 91795825a093331ef136be1d630c5fcad299dfe8)

Conflicts:

	src/libudev/libudev-monitor.c

	src/shared/util.h

---

 src/readahead/readahead-common.c |  6 ++----

 src/shared/util.h                |  6 ++++++

 src/tmpfiles/tmpfiles.c          | 11 ++++-------

 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/readahead/readahead-common.c b/src/readahead/readahead-common.c

index aea1fbe..1edf9cc 100644

--- a/src/readahead/readahead-common.c

+++ b/src/readahead/readahead-common.c

@@ -75,7 +75,7 @@ int fs_on_ssd(const char *p) {

         if (major(st.st_dev) == 0) {

                 _cleanup_fclose_ FILE *f = NULL;

                 int mount_id;

-                struct file_handle *h;

+                union file_handle_union h = { .handle.handle_bytes = MAX_HANDLE_SZ, };

                 /* Might be btrfs, which exposes "ssd" as mount flag if it is on ssd.

                  *

@@ -83,9 +83,7 @@ int fs_on_ssd(const char *p) {

                  * and then lookup the mount ID in mountinfo to find

                  * the mount options. */

-                h = alloca(MAX_HANDLE_SZ);

-                h->handle_bytes = MAX_HANDLE_SZ;

-                r = name_to_handle_at(AT_FDCWD, p, h, &mount_id, AT_SYMLINK_FOLLOW);

+                r = name_to_handle_at(AT_FDCWD, p, &h.handle, &mount_id, AT_SYMLINK_FOLLOW);

                 if (r < 0)

                         return false;

diff --git a/src/shared/util.h b/src/shared/util.h

index 47a3dc9..a173885 100644

--- a/src/shared/util.h

+++ b/src/shared/util.h

@@ -22,6 +22,7 @@

 ***/

 #include <alloca.h>

+#include <fcntl.h>

 #include <inttypes.h>

 #include <time.h>

 #include <sys/time.h>

@@ -776,3 +777,8 @@ static inline void qsort_safe(void *base, size_t nmemb, size_t size,

                 qsort(base, nmemb, size, compar);

         }

 }

+

+union file_handle_union {

+  struct file_handle handle;

+  char padding[sizeof(struct file_handle) + MAX_HANDLE_SZ];

+};

diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c

index fb88acd..98d01a1 100644

--- a/src/tmpfiles/tmpfiles.c

+++ b/src/tmpfiles/tmpfiles.c

@@ -215,19 +215,16 @@ static bool unix_socket_alive(const char *fn) {

 }

 static int dir_is_mount_point(DIR *d, const char *subdir) {

-        struct file_handle *h;

+        union file_handle_union h = { .handle.handle_bytes = MAX_HANDLE_SZ };

         int mount_id_parent, mount_id;

         int r_p, r;

-        h = alloca(MAX_HANDLE_SZ);

-

-        h->handle_bytes = MAX_HANDLE_SZ;

-        r_p = name_to_handle_at(dirfd(d), ".", h, &mount_id_parent, 0);

+        r_p = name_to_handle_at(dirfd(d), ".", &h.handle, &mount_id_parent, 0);

         if (r_p < 0)

                 r_p = -errno;

-        h->handle_bytes = MAX_HANDLE_SZ;

-        r = name_to_handle_at(dirfd(d), subdir, h, &mount_id, 0);

+        h.handle.handle_bytes = MAX_HANDLE_SZ;

+        r = name_to_handle_at(dirfd(d), subdir, &h.handle, &mount_id, 0);

         if (r < 0)

                 r = -errno;