NAK: [J][PATCH 1/2] s390/kexec_file: move kernel image size check

[Frank Heimes]

interesting...
a simple cherry-pick does indeed not work properly ...

I've created a backport, that only adds a bit more context, content-wise
it's the same

re-submit it soon as v2

(apologize)


On Thu, Feb 17, 2022 at 2:05 PM Tim Gardner <tim.gardner at canonical.com>
wrote:

>
>
> On 2/17/22 1:47 AM, Krzysztof Kozlowski wrote:
> > On 17/02/2022 09:30, frank.heimes at canonical.com wrote:
> >> From: Sven Schnelle <svens at linux.ibm.com>
> >>
> >> BugLink: https://bugs.launchpad.net/bugs/1959984
> >>
> >> In preparation of adding support for command lines with variable
> >> sizes on s390, the check whether the new kernel image is at least
> HEAD_END
> >> bytes long isn't correct. Move the check to kexec_file_add_components()
> >> so we can get the size of the parm area and check the size there.
> >>
> >> The '.org HEAD_END' directive can now also be removed from head.S. This
> >> was used in the past to reserve space for the early sccb buffer, but
> with
> >> commit 9a5131b87cac1 ("s390/boot: move sclp early buffer from fixed
> address
> >> in asm to C") this is no longer required.
> >>
> >> Signed-off-by: Sven Schnelle <svens at linux.ibm.com>
> >> Reviewed-by: Heiko Carstens <hca at linux.ibm.com>
> >> Signed-off-by: Vasily Gorbik <gor at linux.ibm.com>
> >> (cherry picked from commit 277c8389386e2ccb8417afe4e36f67fc5dcd735d)
>
> This is a backport.
>
> >> Signed-off-by: Frank Heimes <frank.heimes at canonical.com>
> >> ---
> >>   arch/s390/boot/head.S                 |  2 --
> >>   arch/s390/include/asm/setup.h         |  1 -
> >>   arch/s390/kernel/machine_kexec_file.c | 25 ++-----------------------
> >>   3 files changed, 2 insertions(+), 26 deletions(-)
> >>
> >> diff --git a/arch/s390/boot/head.S b/arch/s390/boot/head.S
> >> index 40f4cff538b8..f3a8dba7dd5d 100644
> >> --- a/arch/s390/boot/head.S
> >> +++ b/arch/s390/boot/head.S
> >> @@ -383,5 +383,3 @@ SYM_DATA_START(parmarea)
> >>      .byte   0
> >>      .org    PARMAREA+__PARMAREA_SIZE
> >>   SYM_DATA_END(parmarea)
> >> -
> >> -    .org    HEAD_END
> >> diff --git a/arch/s390/include/asm/setup.h
> b/arch/s390/include/asm/setup.h
> >> index b6606ffd85d8..121e1a8c41d7 100644
> >> --- a/arch/s390/include/asm/setup.h
> >> +++ b/arch/s390/include/asm/setup.h
> >> @@ -11,7 +11,6 @@
> >>   #include <linux/build_bug.h>
> >>
> >>   #define PARMAREA           0x10400
> >> -#define HEAD_END            0x11000
> >>
> >>   /*
> >>    * Machine features detected in early.c
> >> diff --git a/arch/s390/kernel/machine_kexec_file.c
> b/arch/s390/kernel/machine_kexec_file.c
> >> index a81d6c43b9b6..6944d9abee1e 100644
> >> --- a/arch/s390/kernel/machine_kexec_file.c
> >> +++ b/arch/s390/kernel/machine_kexec_file.c
> >> @@ -235,7 +235,8 @@ void *kexec_file_add_components(struct kimage
> *image,
> >>      if (ret)
> >>              goto out;
> >>
> >> -    if (image->cmdline_buf_len >= ARCH_COMMAND_LINE_SIZE) {
> >> +    if (image->kernel_buf_len < PARMAREA + sizeof(struct parmarea) ||
> >> +        image->cmdline_buf_len >= ARCH_COMMAND_LINE_SIZE) {
> >>              ret = -EINVAL;
> >>              goto out;
> >>      }
> >> @@ -324,25 +325,3 @@ int arch_kexec_apply_relocations_add(struct
> purgatory_info *pi,
> >>      }
> >>      return 0;
> >>   }
> >> -
> >> -int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> >> -                              unsigned long buf_len)
> >> -{
> >> -    /* A kernel must be at least large enough to contain head.S. During
> >> -     * load memory in head.S will be accessed, e.g. to register the
> next
> >> -     * command line. If the next kernel were smaller the current kernel
> >> -     * will panic at load.
> >> -     */
> >> -    if (buf_len < HEAD_END)
> >> -            return -ENOEXEC;
> >> -
> >> -    return kexec_image_probe_default(image, buf, buf_len);
> >> -}
> >> -
> >> -int arch_kimage_file_post_load_cleanup(struct kimage *image)
> >> -{
> >
> > This should stay. It was not part of original commit.
> >
> >> -    vfree(image->arch.ipl_buf);
> >> -    image->arch.ipl_buf = NULL;
> >> -
> >> -    return kexec_image_post_load_cleanup_default(image);
> >> -}
> >
> >
> > Best regards,
> > Krzysztof
> >
>
> --
> -----------
> Tim Gardner
> Canonical, Inc
>
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