From: David Howells <dhowells@redhat.com> To: linux-kernel@vger.kernel.org Cc: matthew.garrett@nebula.com, linux-efi@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk, gregkh@linuxfoundation.org, dhowells@redhat.com, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org Subject: [PATCH 05/24] Restrict /dev/mem and /dev/kmem when the kernel is locked down Date: Wed, 05 Apr 2017 21:15:16 +0100 [thread overview] Message-ID: <149142331660.5101.9920673908924997494.stgit@warthog.procyon.org.uk> (raw) In-Reply-To: <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> From: Matthew Garrett <matthew.garrett@nebula.com> Allowing users to write to address space makes it possible for the kernel to be subverted, avoiding module loading restrictions. Prevent this when the kernel has been locked down. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com> --- drivers/char/mem.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 6d9cc2d39d22..f8144049bda3 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -163,6 +163,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf, if (p != *ppos) return -EFBIG; + if (kernel_is_locked_down()) + return -EPERM; + if (!valid_phys_addr_range(p, count)) return -EFAULT; @@ -513,6 +516,9 @@ 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 (kernel_is_locked_down()) + return -EPERM; + if (p < (unsigned long) high_memory) { unsigned long to_write = min_t(unsigned long, count, (unsigned long)high_memory - p);
WARNING: multiple messages have this Message-ID (diff)
From: dhowells@redhat.com (David Howells) To: linux-security-module@vger.kernel.org Subject: [PATCH 05/24] Restrict /dev/mem and /dev/kmem when the kernel is locked down Date: Wed, 05 Apr 2017 21:15:16 +0100 [thread overview] Message-ID: <149142331660.5101.9920673908924997494.stgit@warthog.procyon.org.uk> (raw) In-Reply-To: <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> From: Matthew Garrett <matthew.garrett@nebula.com> Allowing users to write to address space makes it possible for the kernel to be subverted, avoiding module loading restrictions. Prevent this when the kernel has been locked down. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com> --- drivers/char/mem.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 6d9cc2d39d22..f8144049bda3 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -163,6 +163,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf, if (p != *ppos) return -EFBIG; + if (kernel_is_locked_down()) + return -EPERM; + if (!valid_phys_addr_range(p, count)) return -EFAULT; @@ -513,6 +516,9 @@ 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 (kernel_is_locked_down()) + return -EPERM; + if (p < (unsigned long) high_memory) { unsigned long to_write = min_t(unsigned long, count, (unsigned long)high_memory - p); -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info@ http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2017-04-05 20:15 UTC|newest] Thread overview: 216+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-04-05 20:14 [PATCH 00/24] Kernel lockdown David Howells 2017-04-05 20:14 ` David Howells 2017-04-05 20:14 ` [PATCH 01/24] efi: Add EFI_SECURE_BOOT bit David Howells 2017-04-05 20:14 ` David Howells 2017-04-06 8:26 ` Ard Biesheuvel 2017-04-06 8:26 ` Ard Biesheuvel 2017-04-06 8:48 ` David Howells 2017-04-06 8:48 ` David Howells 2017-04-05 20:14 ` [PATCH 02/24] Add the ability to lock down access to the running kernel image David Howells 2017-04-05 20:14 ` David Howells 2017-04-05 20:14 ` David Howells 2017-04-05 20:14 ` [PATCH 03/24] efi: Lock down the kernel if booted in secure boot mode David Howells 2017-04-05 20:14 ` David Howells 2017-04-05 20:15 ` [PATCH 04/24] Enforce module signatures if the kernel is locked down David Howells 2017-04-05 20:15 ` David Howells 2017-04-05 20:15 ` David Howells [this message] 2017-04-05 20:15 ` [PATCH 05/24] Restrict /dev/mem and /dev/kmem when " David Howells 2017-04-05 20:15 ` [PATCH 06/24] Add a sysrq option to exit secure boot mode David Howells 2017-04-05 20:15 ` David Howells 2017-04-14 18:05 ` Thomas Gleixner 2017-04-14 18:05 ` Thomas Gleixner 2017-04-14 18:05 ` Thomas Gleixner 2017-04-14 18:15 ` Ard Biesheuvel 2017-04-14 18:15 ` Ard Biesheuvel 2017-04-14 18:15 ` Ard Biesheuvel 2017-04-14 23:16 ` David Howells 2017-04-14 23:16 ` David Howells 2017-04-14 23:16 ` David Howells 2017-04-16 20:46 ` Matt Fleming 2017-04-16 20:46 ` Matt Fleming 2017-04-16 20:46 ` Matt Fleming 2017-04-05 20:15 ` [PATCH 07/24] kexec: Disable at runtime if the kernel is locked down David Howells 2017-04-05 20:15 ` David Howells 2017-04-05 20:15 ` David Howells 2017-04-07 3:07 ` Dave Young 2017-04-07 3:07 ` Dave Young 2017-04-07 3:07 ` Dave Young 2017-04-07 3:07 ` Dave Young 2017-04-05 20:15 ` [PATCH 08/24] Copy secure_boot flag in boot params across kexec reboot David Howells 2017-04-05 20:15 ` David Howells 2017-04-05 20:15 ` David Howells 2017-04-05 20:15 ` [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set David Howells 2017-04-05 20:15 ` David Howells 2017-04-05 20:15 ` David Howells 2017-04-05 20:15 ` David Howells 2017-04-07 3:05 ` Dave Young 2017-04-07 3:05 ` Dave Young 2017-04-07 3:05 ` Dave Young 2017-04-07 3:05 ` Dave Young 2017-04-07 3:49 ` Mimi Zohar 2017-04-07 3:49 ` Mimi Zohar 2017-04-07 3:49 ` Mimi Zohar 2017-04-07 6:19 ` Dave Young 2017-04-07 6:19 ` Dave Young 2017-04-07 6:19 ` Dave Young 2017-04-07 6:19 ` Dave Young 2017-04-07 7:45 ` Mimi Zohar 2017-04-07 7:45 ` Mimi Zohar 2017-04-07 7:45 ` Mimi Zohar 2017-04-07 8:01 ` Dave Young 2017-04-07 8:01 ` Dave Young 2017-04-07 8:01 ` Dave Young 2017-04-07 7:07 ` David Howells 2017-04-07 7:07 ` David Howells 2017-04-07 7:07 ` David Howells 2017-04-07 7:41 ` Dave Young 2017-04-07 7:41 ` Dave Young 2017-04-07 7:41 ` Dave Young 2017-04-07 7:41 ` Dave Young 2017-04-07 8:28 ` Mimi Zohar 2017-04-07 8:28 ` Mimi Zohar 2017-04-07 8:28 ` Mimi Zohar 2017-04-07 8:28 ` Mimi Zohar 2017-04-07 8:42 ` Dave Young 2017-04-07 8:42 ` Dave Young 2017-04-07 8:42 ` Dave Young 2017-04-07 8:42 ` Dave Young 2017-04-07 7:09 ` David Howells 2017-04-07 7:09 ` David Howells 2017-04-07 7:09 ` David Howells 2017-04-07 7:46 ` Mimi Zohar 2017-04-07 7:46 ` Mimi Zohar 2017-04-07 7:46 ` Mimi Zohar 2017-04-07 9:17 ` David Howells 2017-04-07 9:17 ` David Howells 2017-04-07 9:17 ` David Howells 2017-04-07 12:36 ` Mimi Zohar 2017-04-07 12:36 ` Mimi Zohar 2017-04-07 12:36 ` Mimi Zohar 2017-04-10 13:19 ` David Howells 2017-04-10 13:19 ` David Howells 2017-04-10 13:19 ` David Howells 2017-05-02 19:01 ` Mimi Zohar 2017-05-02 19:01 ` Mimi Zohar 2017-05-02 19:01 ` Mimi Zohar 2017-05-02 19:01 ` Mimi Zohar 2017-04-05 20:16 ` [PATCH 10/24] hibernate: Disable when the kernel is locked down David Howells 2017-04-05 20:16 ` David Howells 2017-04-05 20:16 ` [PATCH 11/24] uswsusp: " David Howells 2017-04-05 20:16 ` David Howells 2017-04-05 23:38 ` Rafael J. Wysocki 2017-04-05 23:38 ` Rafael J. Wysocki 2017-04-05 23:38 ` Rafael J. Wysocki 2017-04-06 6:39 ` Oliver Neukum 2017-04-06 6:39 ` Oliver Neukum 2017-04-06 8:41 ` David Howells 2017-04-06 8:41 ` David Howells 2017-04-06 20:09 ` Rafael J. Wysocki 2017-04-06 20:09 ` Rafael J. Wysocki 2017-04-06 20:09 ` Rafael J. Wysocki 2017-04-06 20:12 ` Rafael J. Wysocki 2017-04-06 20:12 ` Rafael J. Wysocki 2017-04-06 20:25 ` Jiri Kosina 2017-04-06 20:25 ` Jiri Kosina 2017-04-08 3:28 ` poma 2017-04-08 3:28 ` poma 2017-04-12 13:44 ` joeyli 2017-04-12 13:44 ` joeyli 2017-04-06 6:55 ` David Howells 2017-04-06 6:55 ` David Howells 2017-04-06 20:07 ` Rafael J. Wysocki 2017-04-06 20:07 ` Rafael J. Wysocki 2017-04-05 20:16 ` [PATCH 12/24] PCI: Lock down BAR access " David Howells 2017-04-05 20:16 ` David Howells 2017-04-18 17:50 ` Bjorn Helgaas 2017-04-18 17:50 ` Bjorn Helgaas 2017-04-18 17:50 ` Bjorn Helgaas 2017-04-05 20:16 ` [PATCH 13/24] x86: Lock down IO port " David Howells 2017-04-05 20:16 ` David Howells 2017-04-05 20:16 ` David Howells 2017-04-14 18:28 ` Thomas Gleixner 2017-04-14 18:28 ` Thomas Gleixner 2017-04-14 18:28 ` Thomas Gleixner 2017-04-05 20:16 ` [PATCH 14/24] x86: Restrict MSR " David Howells 2017-04-05 20:16 ` David Howells 2017-04-14 18:30 ` Thomas Gleixner 2017-04-14 18:30 ` Thomas Gleixner 2017-04-05 20:16 ` [PATCH 15/24] asus-wmi: Restrict debugfs interface " David Howells 2017-04-05 20:16 ` David Howells 2017-04-07 10:25 ` Andy Shevchenko 2017-04-07 10:25 ` Andy Shevchenko 2017-04-07 12:50 ` David Howells 2017-04-07 12:50 ` David Howells 2017-04-09 11:10 ` Andy Shevchenko 2017-04-09 11:10 ` Andy Shevchenko 2017-04-10 13:16 ` David Howells 2017-04-10 13:16 ` David Howells 2017-04-18 6:06 ` Andy Shevchenko 2017-04-18 6:06 ` Andy Shevchenko 2017-04-18 6:06 ` Andy Shevchenko 2017-04-18 14:34 ` Ben Hutchings 2017-04-18 14:34 ` Ben Hutchings 2017-04-18 14:55 ` David Howells 2017-04-18 14:55 ` David Howells 2017-04-18 14:55 ` David Howells 2017-04-18 15:19 ` Ben Hutchings 2017-04-18 15:19 ` Ben Hutchings 2017-04-18 15:34 ` David Howells 2017-04-18 15:34 ` David Howells 2017-04-18 15:34 ` David Howells 2017-04-18 15:30 ` David Howells 2017-04-18 15:30 ` David Howells 2017-04-18 17:39 ` Ben Hutchings 2017-04-18 17:39 ` Ben Hutchings 2017-04-18 17:39 ` Ben Hutchings 2017-04-05 20:16 ` [PATCH 16/24] ACPI: Limit access to custom_method " David Howells 2017-04-05 20:16 ` David Howells 2017-04-05 20:16 ` [PATCH 17/24] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells 2017-04-05 20:16 ` David Howells 2017-04-06 19:43 ` Rafael J. Wysocki 2017-04-06 19:43 ` Rafael J. Wysocki 2017-04-07 6:31 ` Dave Young 2017-04-07 6:31 ` Dave Young [not found] ` <20170407063107.GA10451-0VdLhd/A9Pl+NNSt+8eSiB/sF2h8X+2i0E9HWUfgJXw@public.gmane.org> 2017-04-07 7:05 ` David Howells 2017-04-07 7:05 ` David Howells 2017-04-07 7:05 ` David Howells 2017-04-07 7:39 ` Dave Young 2017-04-07 7:39 ` Dave Young 2017-04-05 20:17 ` [PATCH 18/24] acpi: Disable ACPI table override if the kernel is " David Howells 2017-04-05 20:17 ` David Howells 2017-04-05 20:17 ` [PATCH 19/24] acpi: Disable APEI error injection " David Howells 2017-04-05 20:17 ` David Howells 2017-04-05 20:17 ` [PATCH 20/24] bpf: Restrict kernel image access functions when " David Howells 2017-04-05 20:17 ` David Howells 2017-04-06 12:29 ` Alexei Starovoitov 2017-04-06 12:29 ` Alexei Starovoitov 2017-04-06 12:40 ` Ard Biesheuvel 2017-04-06 12:40 ` Ard Biesheuvel 2017-04-12 14:57 ` joeyli 2017-04-12 14:57 ` joeyli 2017-04-12 14:57 ` joeyli 2017-04-13 8:46 ` David Howells 2017-04-13 8:46 ` David Howells 2017-04-05 20:17 ` [PATCH 21/24] scsi: Lock down the eata driver David Howells 2017-04-05 20:17 ` David Howells 2017-04-05 20:17 ` [PATCH 22/24] Prohibit PCMCIA CIS storage when the kernel is locked down David Howells 2017-04-05 20:17 ` David Howells 2017-04-05 20:17 ` David Howells 2017-04-05 20:17 ` [PATCH 23/24] Lock down TIOCSSERIAL David Howells 2017-04-05 20:17 ` David Howells 2017-04-05 20:17 ` David Howells 2017-04-05 20:18 ` [PATCH 24/24] Lock down module params that specify hardware parameters (eg. ioport) David Howells 2017-04-05 20:18 ` David Howells 2017-04-05 20:18 ` David Howells 2017-04-07 15:59 ` [PATCH 00/24] Kernel lockdown Austin S. Hemmelgarn 2017-04-07 15:59 ` Austin S. Hemmelgarn 2017-04-07 16:29 ` Justin Forbes 2017-04-07 16:29 ` Justin Forbes 2017-04-07 16:29 ` Justin Forbes 2017-04-10 23:15 ` Why kernel lockdown? David Howells 2017-04-10 23:15 ` David Howells -- strict thread matches above, loose matches on Subject: below -- 2017-04-05 17:09 [PATCH 00/24] Kernel lockdown David Howells 2017-04-05 17:10 ` [PATCH 05/24] Restrict /dev/mem and /dev/kmem when the kernel is locked down David Howells 2017-04-05 17:10 ` David Howells 2017-04-05 17:07 [PATCH 00/24] Kernel lockdown David Howells 2017-04-05 17:07 ` [PATCH 05/24] Restrict /dev/mem and /dev/kmem when the kernel is locked down David Howells 2017-04-05 17:07 ` David Howells 2017-04-05 17:07 ` David Howells
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