On Wed, Apr 23, 2025 at 10:59:06PM +0200, Arnaud Lefebvre wrote:
diff --git a/arch/x86/kernel/kexec-bzimage64.c
b/arch/x86/kernel/kexec-bzimage64.c
index 68530fad05f7..5604a5109858 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -76,6 +76,10 @@ static int setup_cmdline(struct kimage *image, struct
boot_params *params,
if (image->type == KEXEC_TYPE_CRASH) {
len = sprintf(cmdline_ptr,
"elfcorehdr=0x%lx ", image->elf_load_addr);
+
+ if (image->dm_crypt_keys_addr != 0)
+ len += sprintf(cmdline_ptr + len,
+ "dmcryptkeys=0x%lx ",
image->dm_crypt_keys_addr);
sprintf will return the length of dmcryptkey=xxx which will be added to
len.
}
memcpy(cmdline_ptr + len, cmdline, cmdline_len);
cmdline_len += len;
Then cmdline_len will included the new len.
You are adding another kernel parameter but I believe without taking its
length into account. See the MAX_ELFCOREHDR_STR_LEN constant which is added to
the
params_cmdline_sz variable for the elfcorehdr= parameter.
Thanks for raising the concern! I believe this issue has already been
took care of. Please check the above two inline comments:)
This will (at least during my tests) truncate the cmdline given to the crash
kernel because
the next section (efi_map_offset) will have an offset starting inside the
cmdline section
and it might overwrite the end of it:
kexec-bzimage64.c:480:
params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
MAX_ELFCOREHDR_STR_LEN; <<< Should have + 31 here for
"dmcryptkeys=0x<ptr> "
params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
sizeof(struct setup_data) +
sizeof(struct efi_setup_data) +
sizeof(struct setup_data) +
RNG_SEED_LENGTH;
And I believe the buffer might be too small.
Also, there is another check a few lines above that needs to take the size into
account:
/*
* In case of crash dump, we will append elfcorehdr=<addr> to
* command line. Make sure it does not overflow
*/
if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed
length\n");
return ERR_PTR(-EINVAL);
}
--
Best regards,
Coiby
