[PATCH v2] libebl: recognize FDO Packaging Metadata ELF note

[Luca Boccassi]

On Sun, 2021-11-21 at 19:43 +0000, luca.boccassi@gmail.com wrote:
> From: Luca Boccassi <bluca@debian.org>
> 
> As defined on: https://systemd.io/COREDUMP_PACKAGE_METADATA/
> this note will be used starting from Fedora 36. Allow
> readelf --notes to pretty print it:
> 
> Note section [ 3] '.note.package' of 76 bytes at offset 0x2e8:
>   Owner          Data size  Type
>   FDO                   57  FDO_PACKAGING_METADATA
>     Packaging Metadata: {"type":"deb","name":"fsverity-utils","version":"1.3-1"}
> 
> Signed-off-by: Luca Boccassi <luca.boccassi@microsoft.com>
> ---
> v2: check that note payload is NULL terminated
> 
>  libebl/eblobjnote.c         | 3 +++
>  libebl/eblobjnotetypename.c | 3 +++
>  libelf/elf.h                | 3 +++
>  3 files changed, 9 insertions(+)
> 
> diff --git a/libebl/eblobjnote.c b/libebl/eblobjnote.c
> index 36efe275..e3ad1409 100644
> --- a/libebl/eblobjnote.c
> +++ b/libebl/eblobjnote.c
> @@ -288,6 +288,9 @@ ebl_object_note (Ebl *ebl, uint32_t namesz, const char *name, uint32_t type,
>        if (descsz == 0 && type == NT_VERSION)
>  	return;
>  
> 
> 
> 
> +      if (strcmp ("FDO", name) == 0 && type == FDO_PACKAGING_METADATA && descsz > 0 && desc[descsz - 1] == '\0')
> +	printf("    Packaging Metadata: %.*s\n", (int) descsz, desc);
> +
>        /* Everything else should have the "GNU" owner name.  */
>        if (strcmp ("GNU", name) != 0)
>  	return;
> diff --git a/libebl/eblobjnotetypename.c b/libebl/eblobjnotetypename.c
> index 4662906d..863f20e4 100644
> --- a/libebl/eblobjnotetypename.c
> +++ b/libebl/eblobjnotetypename.c
> @@ -101,6 +101,9 @@ ebl_object_note_type_name (Ebl *ebl, const char *name, uint32_t type,
>  	  return buf;
>  	}
>  
> 
> 
> 
> +      if (strcmp (name, "FDO") == 0 && type == FDO_PACKAGING_METADATA)
> +	return "FDO_PACKAGING_METADATA";
> +
>        if (strcmp (name, "GNU") != 0)
>  	{
>  	  /* NT_VERSION is special, all data is in the name.  */
> diff --git a/libelf/elf.h b/libelf/elf.h
> index 8e3e618f..633f9f67 100644
> --- a/libelf/elf.h
> +++ b/libelf/elf.h
> @@ -1297,6 +1297,9 @@ typedef struct
>  /* Program property.  */
>  #define NT_GNU_PROPERTY_TYPE_0 5
>  
> 
> 
> 
> +/* Packaging metadata as defined on https://systemd.io/COREDUMP_PACKAGE_METADATA/ */
> +#define FDO_PACKAGING_METADATA 0xcafe1a7e
> +
>  /* Note section name of program property.   */
>  #define NOTE_GNU_PROPERTY_SECTION_NAME ".note.gnu.property"

Hi Mark,

I could move this definition to an internal header if the change to
elf.h blocks this patch, if you prefer? Let me know.

-- 
Kind regards,
Luca Boccassi
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