[PATCH v3 04/21] vmcore,sysfs: export ELF note segment size instead of vmcoreinfo data size

[HATAYAMA Daisuke]

Currently, vmcoreinfo exports data part only, but kexec-tool sets it
in p_memsz member as a whole ELF note segment size. Due to this, it
would be no problem on the current ELF note segment size, but if it
grows in the future, then read possibly doesn't reach ELF note header
in larger p_memsz position, failing to read a whole ELF segment.

Note: kexec-tools assigns PAGE_SIZE to p_memsz for other ELF note
types. Due to the above reason, the same issue occurs if actual ELF
note data exceeds (PAGE_SIZE - 2 * KEXEC_NOTE_HEAD_BYTES).

Signed-off-by: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
---

 kernel/ksysfs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index 6ada93c..97d2763 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -126,7 +126,7 @@ static ssize_t vmcoreinfo_show(struct kobject *kobj,
 {
 	return sprintf(buf, "%lx %x\n",
 		       paddr_vmcoreinfo_note(),
-		       (unsigned int)vmcoreinfo_max_size);
+		       (unsigned int)sizeof(vmcoreinfo_note));
 }
 KERNEL_ATTR_RO(vmcoreinfo);
 

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