[PATCH v2 03/20] vmcore,sysfs: export ELF note segment size instead of vmcoreinfo data size

[HATAYAMA Daisuke]

p_memsz member of program header entry with PT_NOTE type needs to have
size of the corresponding ELF note segment. Currently, vmcoreinfo
exports data part only. If vmcoreinfo reachs vmcoreinfo_max_size, then
in merge_note_headers_elf{32,64}, empty ELF note header cannot be
found or buffer overrun can happen.

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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