[PATCH 2/2] kernel/kexec: Fix IMA when allocation happens in CMA area

[Pingfan Liu]

When I tested kexec with the latest kernel, I ran into the following warning:

[   40.712410] ------------[ cut here ]------------
[   40.712576] WARNING: CPU: 2 PID: 1562 at kernel/kexec_core.c:1001 kimage_map_segment+0x144/0x198
[...]
[   40.816047] Call trace:
[   40.818498]  kimage_map_segment+0x144/0x198 (P)
[   40.823221]  ima_kexec_post_load+0x58/0xc0
[   40.827246]  __do_sys_kexec_file_load+0x29c/0x368
[...]
[   40.855423] ---[ end trace 0000000000000000 ]---

This is caused by the fact that kexec allocates the destination directly
in the CMA area. In that case, the CMA kernel address should be exported
directly to the IMA component, instead of using the vmalloc'd address.

Signed-off-by: Pingfan Liu <piliu at redhat.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Baoquan He <bhe at redhat.com>
Cc: Alexander Graf <graf at amazon.com>
Cc: Steven Chen <chenste at linux.microsoft.com>
Cc: linux-integrity at vger.kernel.org
To: kexec at lists.infradead.org
---
 kernel/kexec_core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 9a1966207041..abe40286a02c 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -967,6 +967,7 @@ void *kimage_map_segment(struct kimage *image, int idx)
 	kimage_entry_t *ptr, entry;
 	struct page **src_pages;
 	unsigned int npages;
+	struct page *cma;
 	void *vaddr = NULL;
 	int i;
 
@@ -974,6 +975,9 @@ void *kimage_map_segment(struct kimage *image, int idx)
 	size = image->segment[idx].memsz;
 	eaddr = addr + size;
 
+	cma = image->segment_cma[idx];
+	if (cma)
+		return cma;
 	/*
 	 * Collect the source pages and map them in a contiguous VA range.
 	 */
@@ -1014,7 +1018,8 @@ void *kimage_map_segment(struct kimage *image, int idx)
 
 void kimage_unmap_segment(void *segment_buffer)
 {
-	vunmap(segment_buffer);
+	if (is_vmalloc_addr(segment_buffer))
+		vunmap(segment_buffer);
 }
 
 struct kexec_load_limit {
-- 
2.49.0