From: Jean Delvare Date: Sat, 3 Feb 2018 10:25:20 +0000 (+0100) Subject: firmware: dmi_scan: Fix handling of empty DMI strings X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8d4bc4c9b764f294f639887aca19265133048f1c;p=pandora-kernel.git firmware: dmi_scan: Fix handling of empty DMI strings commit a7770ae194569e96a93c48aceb304edded9cc648 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 Fixes: 79da4721117f ("x86: fix DMI out of memory problems") Cc: Parag Warudkar Cc: Ingo Molnar Cc: Thomas Gleixner Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed