commit a7770ae194 upstream.
The handling of empty DMI strings looks quite broken to me:
* Strings from 1 to 7 spaces are not considered empty.
* True empty DMI strings (string index set to 0) are not considered
empty, and result in allocating a 0-char string.
* Strings with invalid index also result in allocating a 0-char
string.
* Strings starting with 8 spaces are all considered empty, even if
non-space characters follow (sounds like a weird thing to do, but
I have actually seen occurrences of this in DMI tables before.)
* Strings which are considered empty are reported as 8 spaces,
instead of being actually empty.
Some of these issues are the result of an off-by-one error in memcmp,
the rest is incorrect by design.
So let's get it square: missing strings and strings made of only
spaces, regardless of their length, should be treated as empty and
no memory should be allocated for them. All other strings are
non-empty and should be allocated.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Fixes: 79da472111 ("x86: fix DMI out of memory problems")
Cc: Parag Warudkar <parag.warudkar@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
8d4bc4c9b7