On Tue, Jun 04, 2024 at 04:51:03PM +0800, Baoquan He wrote:
Hi Coiby,
Hi Baoquan,
On 05/23/24 at 01:04pm, Coiby Xu wrote:
A sysfs /sys/kernel/crash_dm_crypt_keys is provided for user space to make
the dm crypt keys persist for the kdump kernel. User space can send the
following commands,
- "init KEY_NUM"
Initialize needed structures
- "record KEY_DESC"
Record a key description. The key must be a logon key.
User space can also read this API to learn about current state.
From the subject, can I think the luks keys will persist forever? or
only for a while?
Yes, you are right. The keys need to stay in kdump reserved memory.
If need and can only keep it for a while, can you
mention it and tell why and how it will be used. Because you add a lot
of codes, but only simply mention the sysfs, that doesn't make sense.
Thanks for raising the concern! I've added
Documentation/ABI/testing/crash_dm_crypt_keys and copy some text in the
cover letter to this patch in v5.
Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx>
---
include/linux/crash_core.h | 5 +-
kernel/Kconfig.kexec | 8 +++
kernel/Makefile | 1 +
kernel/crash_dump_dm_crypt.c | 113 +++++++++++++++++++++++++++++++++++
kernel/ksysfs.c | 22 +++++++
5 files changed, 148 insertions(+), 1 deletion(-)
create mode 100644 kernel/crash_dump_dm_crypt.c
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 44305336314e..6bff1c24efa3 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -34,7 +34,10 @@ static inline void arch_kexec_protect_crashkres(void) { }
static inline void arch_kexec_unprotect_crashkres(void) { }
#endif
[...]
+static int init(const char *buf)
~~~~ A more interesting name with more description?
Thanks for the suggestion! I've added some comments for this function
in v5. But I can't come up with a better name after looking at current
kernel code. You are welcome to suggest any better name:)
+static int process_cmd(const char *buf, size_t count)
~~~~
If nobody use the count, why do you add it?
Good catch! Yes, this is no need to use count in v4. But v5 now needs it to avoid
buffer overflow.
--
Best regards,
Coiby
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