41 lines
1.5 KiB
Diff
41 lines
1.5 KiB
Diff
From: Chun-Yi Lee <joeyli.kernel@gmail.com>
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Date: Wed, 8 Nov 2017 15:11:33 +0000
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Subject: [08/29] kexec_file: Restrict at runtime if the kernel is locked down
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Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=eed4aca0409692d7d24bc64f5c98d346cd0506c4
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When KEXEC_VERIFY_SIG is not enabled, kernel should not load images through
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kexec_file systemcall if the kernel is locked down unless IMA can be used
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to validate the image.
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This code was showed in Matthew's patch but not in git:
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https://lkml.org/lkml/2015/3/13/778
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Cc: Matthew Garrett <mjg59@srcf.ucam.org>
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Signed-off-by: Chun-Yi Lee <jlee@suse.com>
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Signed-off-by: David Howells <dhowells@redhat.com>
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Reviewed-by: James Morris <james.l.morris@oracle.com>
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cc: kexec@lists.infradead.org
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---
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kernel/kexec_file.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
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index 9f48f4412297..3ba28fc3fab0 100644
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--- a/kernel/kexec_file.c
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+++ b/kernel/kexec_file.c
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@@ -255,6 +255,14 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
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if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
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return -EPERM;
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+ /* Don't permit images to be loaded into trusted kernels if we're not
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+ * going to verify the signature on them
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+ */
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+ if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) &&
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+ !is_ima_appraise_enabled() &&
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+ kernel_is_locked_down("kexec of unsigned images"))
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+ return -EPERM;
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+
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/* Make sure we have a legal set of flags */
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if (flags != (flags & KEXEC_FILE_FLAGS))
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return -EINVAL;
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