Messages in this thread Patch in this message | | | Date | Mon, 15 Jan 2007 16:03:49 +0100 | From | Cedric Le Goater <> | Subject | Re: [PATCH -mm 7/8] user_ns: handle file sigio |
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Serge E. Hallyn wrote: > Quoting Andrew Morton (akpm@osdl.org): >> On Thu, 4 Jan 2007 12:12:57 -0600 >> "Serge E. Hallyn" <serue@us.ibm.com> wrote: >> >>> A process in one user namespace could set a fowner and sigio on a file in a >>> shared vfsmount, ending up killing a task in another user namespace. >>> >>> Prevent this by adding a user namespace pointer to the fown_struct, and >>> enforcing that a process causing a signal to be sent be in the same >>> user namespace as the file owner. >> This patch breaks the X server (stock FC5 install) with CONFIG_USER_NS=n. >> Neither the USB mouse nor the trackpad work. They work OK under GPM. >> >> Setting CONFIG_USER_NS=y "fixes" this. This bug was not observed in >> 2.6.20-rc3-mm1 because that kernel had user-ns-always-on.patch for other >> reasons. (I'll restore that patch). >> >> There's nothing very interesting here: > [ ... ] > > I can't see any reason for this in the code or comparative ltp runs. > Cedric is testing on a fc6 laptop, hopefully he can reproduce it.
I did reproduce it on a FC5 desktop finally.
get_user_ns() returns NULL when CONFIG_USER_NS=n and this breaks sigio_perm() which does not expect NULL values for ->user_ns.
I would fix this with the following patch.
C.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
--- include/linux/user_namespace.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: 2.6.20-rc4-mm1/include/linux/user_namespace.h =================================================================== --- 2.6.20-rc4-mm1.orig/include/linux/user_namespace.h +++ 2.6.20-rc4-mm1/include/linux/user_namespace.h @@ -49,7 +49,7 @@
static inline struct user_namespace *get_user_ns(struct user_namespace *ns) { - return NULL; + return &init_user_ns; }
static inline int unshare_user_ns(unsigned long flags, - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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