[SeaBIOS] [PATCH] smbios: catch zero-length strings
Markus Armbruster
armbru at redhat.com
Tue Jan 21 14:26:42 CET 2014
Gerd Hoffmann <kraxel at redhat.com> writes:
> qemu may pass us zero-length strings for smbios fields, when starting
> qemu this way ...
>
> qemu -smbios type=1,version=,serial=test
>
> ... for example.
>
> Today we don't specifically handle them and simply append them to the
> string list. Therefore we get two string-terminating zeros in a row.
> Result is that we by accident create a end-of-entry marker in the middle
> of the entry.
And dmidecode screaming bloody murder :) More detail than you probably
want to know at https://bugzilla.redhat.com/show_bug.cgi?id=1052837
> Fix this by handling zero-length strings like non-present strings.
>
> Cc: armbru at redhat.com
> Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
Spelling correction inline.
Reviewed-by: Markus Armbruster <armbru at redhat.com>
> ---
> src/fw/smbios.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/src/fw/smbios.c b/src/fw/smbios.c
> index affb9be..d549329 100644
> --- a/src/fw/smbios.c
> +++ b/src/fw/smbios.c
> @@ -133,20 +133,24 @@ get_external(int type, char **p, unsigned *nr_structs,
> do { \
> size = get_field(type, offsetof(struct smbios_type_##type, \
> field), end); \
> - if (size > 0) { \
> + if (size == 1) { \
> + /* zero-length string, skip to avoid bogous end marker */ \
s/bogous/bogus/
> + p->field = 0; \
> + } else if (size > 1) { \
> end += size; \
> + p->field = ++str_index; \
> } else { \
> memcpy(end, def, sizeof(def)); \
> end += sizeof(def); \
> + p->field = ++str_index; \
> } \
> - p->field = ++str_index; \
> } while (0)
>
> #define load_str_field_or_skip(type, field) \
> do { \
> size = get_field(type, offsetof(struct smbios_type_##type, \
> field), end); \
> - if (size > 0) { \
> + if (size > 1) { \
> end += size; \
> p->field = ++str_index; \
> } else { \
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