The header description for xs_open() goes as far as to suggest that the fd is
O_CLOEXEC, but it isn't actually.

`xl devd` has been observed leaking /dev/xen/xenbus into children.

Link: https://github.com/QubesOS/qubes-issues/issues/8292
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Anthony PERARD <anthony@xenproject.org>
CC: Juergen Gross <jgross@suse.com>
CC: Demi Marie Obenour <demi@invisiblethingslab.com>
CC: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

Entirely speculative patch based on a Matrix report
---
 tools/libs/store/xs.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c
index 140b9a28395e..1f74fb3c44a2 100644
--- a/tools/libs/store/xs.c
+++ b/tools/libs/store/xs.c
@@ -54,6 +54,10 @@ struct xs_stored_msg {
 #include <dlfcn.h>
 #endif
 
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+
 struct xs_handle {
 	/* Communications channel to xenstore daemon. */
 	int fd;
@@ -227,7 +231,7 @@ static int get_socket(const char *connect_to)
 static int get_dev(const char *connect_to)
 {
 	/* We cannot open read-only because requests are writes */
-	return open(connect_to, O_RDWR);
+	return open(connect_to, O_RDWR|O_CLOEXEC);
 }
 
 static int all_restrict_cb(Xentoolcore__Active_Handle *ah, domid_t domid) {

base-commit: feb9158a620040846d76981acbe8ea9e2255a07b
-- 
2.30.2

On 04.05.24 03:16, Andrew Cooper wrote:
> The header description for xs_open() goes as far as to suggest that the fd is
> O_CLOEXEC, but it isn't actually.
> 
> `xl devd` has been observed leaking /dev/xen/xenbus into children.
> 
> Link: https://github.com/QubesOS/qubes-issues/issues/8292
> Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

With the style breakage below fixed:

Reviewed-by: Juergen Gross <jgross@suse.com>

> ---
> CC: Anthony PERARD <anthony@xenproject.org>
> CC: Juergen Gross <jgross@suse.com>
> CC: Demi Marie Obenour <demi@invisiblethingslab.com>
> CC: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
> 
> Entirely speculative patch based on a Matrix report
> ---
>   tools/libs/store/xs.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c
> index 140b9a28395e..1f74fb3c44a2 100644
> --- a/tools/libs/store/xs.c
> +++ b/tools/libs/store/xs.c
> @@ -54,6 +54,10 @@ struct xs_stored_msg {
>   #include <dlfcn.h>
>   #endif
>   
> +#ifndef O_CLOEXEC
> +#define O_CLOEXEC 0
> +#endif
> +
>   struct xs_handle {
>   	/* Communications channel to xenstore daemon. */
>   	int fd;
> @@ -227,7 +231,7 @@ static int get_socket(const char *connect_to)
>   static int get_dev(const char *connect_to)
>   {
>   	/* We cannot open read-only because requests are writes */
> -	return open(connect_to, O_RDWR);
> +	return open(connect_to, O_RDWR|O_CLOEXEC);

Nit: spaces around the "|", please.


Juergen

>   }
>   
>   static int all_restrict_cb(Xentoolcore__Active_Handle *ah, domid_t domid) {
> 
> base-commit: feb9158a620040846d76981acbe8ea9e2255a07b