Re: [PATCH 07/24] kexec: Disable at runtime if the kernel is locked down
On 04/05/17 at 09:15pm, David Howells wrote: > From: Matthew Garrett > > kexec permits the loading and execution of arbitrary code in ring 0, which > is something that lock-down is meant to prevent. It makes sense to disable > kexec in this situation. > > This does not affect kexec_file_load() which can check for a signature on the > image to be booted. > > Signed-off-by: Matthew Garrett > Signed-off-by: David Howells > cc: ke...@lists.infradead.org > --- > > kernel/kexec.c |7 +++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/kexec.c b/kernel/kexec.c > index 980936a90ee6..46de8e6b42f4 100644 > --- a/kernel/kexec.c > +++ b/kernel/kexec.c > @@ -194,6 +194,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, > unsigned long, nr_segments, > return -EPERM; > > /* > + * kexec can be used to circumvent module loading restrictions, so > + * prevent loading in that case > + */ > + if (kernel_is_locked_down()) > + return -EPERM; > + > + /* >* Verify we have a legal set of flags >* This leaves us room for future extensions. >*/ > > > ___ > kexec mailing list > ke...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec Acked-by: Dave Young Thanks Dave
[PATCH 07/24] kexec: Disable at runtime if the kernel is locked down
From: Matthew Garrett kexec permits the loading and execution of arbitrary code in ring 0, which is something that lock-down is meant to prevent. It makes sense to disable kexec in this situation. This does not affect kexec_file_load() which can check for a signature on the image to be booted. Signed-off-by: Matthew Garrett Signed-off-by: David Howells cc: ke...@lists.infradead.org --- kernel/kexec.c |7 +++ 1 file changed, 7 insertions(+) diff --git a/kernel/kexec.c b/kernel/kexec.c index 980936a90ee6..46de8e6b42f4 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -194,6 +194,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, return -EPERM; /* +* kexec can be used to circumvent module loading restrictions, so +* prevent loading in that case +*/ + if (kernel_is_locked_down()) + return -EPERM; + + /* * Verify we have a legal set of flags * This leaves us room for future extensions. */
[PATCH 07/24] kexec: Disable at runtime if the kernel is locked down
From: Matthew Garrett kexec permits the loading and execution of arbitrary code in ring 0, which is something that lock-down is meant to prevent. It makes sense to disable kexec in this situation. This does not affect kexec_file_load() which can check for a signature on the image to be booted. Signed-off-by: Matthew Garrett Signed-off-by: David Howells --- kernel/kexec.c |7 +++ 1 file changed, 7 insertions(+) diff --git a/kernel/kexec.c b/kernel/kexec.c index 980936a90ee6..46de8e6b42f4 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -194,6 +194,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, return -EPERM; /* +* kexec can be used to circumvent module loading restrictions, so +* prevent loading in that case +*/ + if (kernel_is_locked_down()) + return -EPERM; + + /* * Verify we have a legal set of flags * This leaves us room for future extensions. */
[PATCH 07/24] kexec: Disable at runtime if the kernel is locked down
From: Matthew Garrett kexec permits the loading and execution of arbitrary code in ring 0, which is something that lock-down is meant to prevent. It makes sense to disable kexec in this situation. This does not affect kexec_file_load() which can check for a signature on the image to be booted. Signed-off-by: Matthew Garrett Signed-off-by: David Howells --- kernel/kexec.c |7 +++ 1 file changed, 7 insertions(+) diff --git a/kernel/kexec.c b/kernel/kexec.c index 980936a90ee6..46de8e6b42f4 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -194,6 +194,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, return -EPERM; /* +* kexec can be used to circumvent module loading restrictions, so +* prevent loading in that case +*/ + if (kernel_is_locked_down()) + return -EPERM; + + /* * Verify we have a legal set of flags * This leaves us room for future extensions. */