From: James Morris <jmorris@namei.org> To: Matthew Garrett <matthew.garrett@nebula.com> Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, keescook@chromium.org, hpa@zytor.com Subject: Re: [PATCH V3 06/11] Restrict /dev/mem and /dev/kmem when module loading is restricted Date: Wed, 4 Sep 2013 10:47:19 +1000 (EST) [thread overview] Message-ID: <alpine.LRH.2.02.1309041047110.20116@tundra.namei.org> (raw) In-Reply-To: <1378252218-18798-7-git-send-email-matthew.garrett@nebula.com> On Tue, 3 Sep 2013, Matthew Garrett wrote: > Allowing users to write to address space makes it possible for the kernel > to be subverted, avoiding module loading restrictions. Prevent this when > any restrictions have been imposed on loading modules. > > Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Reviewed-by: James Morris <jmorris@namei.org> > --- > drivers/char/mem.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/char/mem.c b/drivers/char/mem.c > index 1af8664..61406c8 100644 > --- a/drivers/char/mem.c > +++ b/drivers/char/mem.c > @@ -159,6 +159,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf, > unsigned long copied; > void *ptr; > > + if (secure_modules()) > + return -EPERM; > + > if (!valid_phys_addr_range(p, count)) > return -EFAULT; > > @@ -497,6 +500,9 @@ static ssize_t write_kmem(struct file *file, const char __user *buf, > char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ > int err = 0; > > + if (secure_modules()) > + return -EPERM; > + > if (p < (unsigned long) high_memory) { > unsigned long to_write = min_t(unsigned long, count, > (unsigned long)high_memory - p); > -- > 1.8.3.1 > > -- > 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/ > -- James Morris <jmorris@namei.org>
WARNING: multiple messages have this Message-ID (diff)
From: James Morris <jmorris-gx6/JNMH7DfYtjvyW6yDsg@public.gmane.org> To: Matthew Garrett <matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org> Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org Subject: Re: [PATCH V3 06/11] Restrict /dev/mem and /dev/kmem when module loading is restricted Date: Wed, 4 Sep 2013 10:47:19 +1000 (EST) [thread overview] Message-ID: <alpine.LRH.2.02.1309041047110.20116@tundra.namei.org> (raw) In-Reply-To: <1378252218-18798-7-git-send-email-matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org> On Tue, 3 Sep 2013, Matthew Garrett wrote: > Allowing users to write to address space makes it possible for the kernel > to be subverted, avoiding module loading restrictions. Prevent this when > any restrictions have been imposed on loading modules. > > Signed-off-by: Matthew Garrett <matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org> Reviewed-by: James Morris <jmorris-gx6/JNMH7DfYtjvyW6yDsg@public.gmane.org> > --- > drivers/char/mem.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/char/mem.c b/drivers/char/mem.c > index 1af8664..61406c8 100644 > --- a/drivers/char/mem.c > +++ b/drivers/char/mem.c > @@ -159,6 +159,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf, > unsigned long copied; > void *ptr; > > + if (secure_modules()) > + return -EPERM; > + > if (!valid_phys_addr_range(p, count)) > return -EFAULT; > > @@ -497,6 +500,9 @@ static ssize_t write_kmem(struct file *file, const char __user *buf, > char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ > int err = 0; > > + if (secure_modules()) > + return -EPERM; > + > if (p < (unsigned long) high_memory) { > unsigned long to_write = min_t(unsigned long, count, > (unsigned long)high_memory - p); > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- James Morris <jmorris-gx6/JNMH7DfYtjvyW6yDsg@public.gmane.org>
next prev parent reply other threads:[~2013-09-04 0:45 UTC|newest] Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-09-03 23:50 Matthew Garrett 2013-09-03 23:50 ` (unknown), Matthew Garrett 2013-09-03 23:50 ` [PATCH V3 01/11] Add secure_modules() call Matthew Garrett 2013-09-04 0:45 ` James Morris 2013-09-04 0:45 ` James Morris 2013-09-05 2:14 ` joeyli 2013-09-05 2:14 ` joeyli 2013-09-03 23:50 ` [PATCH V3 02/11] PCI: Lock down BAR access when module security is enabled Matthew Garrett 2013-09-04 0:45 ` James Morris 2013-09-04 0:45 ` James Morris 2013-09-04 16:57 ` David Woodhouse 2013-09-04 16:57 ` David Woodhouse 2013-09-04 17:04 ` Matthew Garrett 2013-09-04 17:04 ` Matthew Garrett 2013-09-04 18:58 ` David Woodhouse 2013-09-04 19:01 ` Matthew Garrett 2013-09-04 19:01 ` Matthew Garrett 2013-09-04 19:31 ` David Woodhouse 2013-09-04 19:31 ` David Woodhouse 2013-09-03 23:50 ` [PATCH V3 03/11] x86: Lock down IO port " Matthew Garrett 2013-09-04 0:45 ` James Morris 2013-09-05 3:52 ` H. Peter Anvin 2013-09-05 3:52 ` H. Peter Anvin 2013-09-05 3:58 ` Matthew Garrett 2013-09-05 3:58 ` Matthew Garrett 2013-09-05 15:36 ` H. Peter Anvin 2013-09-05 15:36 ` H. Peter Anvin 2013-09-03 23:50 ` [PATCH V3 04/11] ACPI: Limit access to custom_method Matthew Garrett 2013-09-04 0:46 ` James Morris 2013-09-04 0:46 ` James Morris 2013-09-03 23:50 ` [PATCH V3 05/11] asus-wmi: Restrict debugfs interface when module loading is restricted Matthew Garrett 2013-09-04 0:46 ` James Morris 2013-09-04 0:46 ` James Morris 2013-09-03 23:50 ` [PATCH V3 06/11] Restrict /dev/mem and /dev/kmem " Matthew Garrett 2013-09-04 0:47 ` James Morris [this message] 2013-09-04 0:47 ` James Morris 2013-09-03 23:50 ` [PATCH V3 07/11] acpi: Ignore acpi_rsdp kernel parameter " Matthew Garrett 2013-09-03 23:50 ` Matthew Garrett 2013-09-03 23:50 ` [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions Matthew Garrett 2013-09-04 0:48 ` James Morris 2013-09-04 0:48 ` James Morris 2013-09-04 20:09 ` jerry.hoemann 2013-09-04 20:09 ` jerry.hoemann-VXdhtT5mjnY 2013-09-04 20:12 ` Matthew Garrett 2013-09-04 20:12 ` Matthew Garrett 2013-09-04 20:12 ` Matthew Garrett 2013-09-04 20:14 ` Josh Boyer 2013-09-04 20:14 ` Josh Boyer 2013-09-04 20:14 ` Josh Boyer 2013-09-08 6:40 ` Greg KH 2013-09-08 6:40 ` Greg KH 2013-09-08 6:44 ` Matthew Garrett 2013-09-08 6:44 ` Matthew Garrett 2013-09-08 7:24 ` Greg KH 2013-09-08 7:24 ` Greg KH 2013-09-08 14:40 ` Matthew Garrett 2013-09-08 14:40 ` Matthew Garrett 2013-09-08 15:51 ` Kees Cook 2013-09-08 15:51 ` Kees Cook 2013-09-08 16:18 ` Greg KH 2013-09-08 16:18 ` Greg KH 2013-09-08 16:24 ` Matthew Garrett 2013-09-08 16:24 ` Matthew Garrett 2013-09-08 16:39 ` Greg KH 2013-09-08 16:39 ` Greg KH 2013-09-08 16:59 ` Matthew Garrett 2013-09-08 16:59 ` Matthew Garrett 2013-09-08 17:22 ` Greg KH 2013-09-08 17:22 ` Greg KH 2013-09-08 17:25 ` Matthew Garrett 2013-09-08 17:25 ` Matthew Garrett 2013-09-08 17:11 ` James Bottomley 2013-09-08 17:11 ` James Bottomley 2013-09-08 17:15 ` Matthew Garrett 2013-09-08 17:15 ` Matthew Garrett 2013-09-08 17:22 ` James Bottomley 2013-09-08 17:22 ` James Bottomley 2013-09-08 17:27 ` Matthew Garrett 2013-09-08 17:27 ` Matthew Garrett 2013-09-08 17:32 ` James Bottomley 2013-09-08 17:32 ` James Bottomley 2013-09-08 17:38 ` Matthew Garrett 2013-09-08 17:38 ` Matthew Garrett 2013-09-03 23:50 ` [PATCH V3 09/11] uswsusp: Disable when module loading is restricted Matthew Garrett 2013-09-04 0:48 ` James Morris 2013-09-04 0:48 ` James Morris 2013-09-05 3:20 ` joeyli 2013-09-05 3:20 ` joeyli 2013-09-03 23:50 ` [PATCH V3 10/11] x86: Restrict MSR access " Matthew Garrett 2013-09-04 0:49 ` James Morris 2013-09-04 0:49 ` James Morris 2013-09-03 23:50 ` [PATCH V3 11/11] Add option to automatically enforce module signatures when in Secure Boot mode Matthew Garrett 2013-09-03 23:50 ` Matthew Garrett 2013-09-04 1:42 ` James Morris 2013-09-04 1:42 ` James Morris 2013-09-04 1:42 ` Matthew Garrett 2013-09-04 1:42 ` Matthew Garrett 2013-09-05 3:13 ` joeyli 2013-09-05 8:24 ` joeyli 2013-09-05 8:24 ` joeyli 2013-09-05 10:16 ` Matt Fleming 2013-09-05 10:16 ` Matt Fleming 2013-09-05 12:54 ` Matthew Garrett 2013-09-05 12:54 ` Matthew Garrett 2013-09-04 15:53 ` Kees Cook 2013-09-04 15:53 ` Re: Kees Cook 2013-09-04 16:05 ` Re: Josh Boyer 2013-09-04 16:05 ` Re: Josh Boyer
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