From: Dave Hansen Date: Tue, 22 Dec 2015 22:52:39 +0000 (-0800) Subject: x86/boot: Fix early command-line parsing when partial word matches X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8b704b1f32a509d7254581a9109a4f7dda9669c1;p=pandora-kernel.git x86/boot: Fix early command-line parsing when partial word matches commit abcdc1c694fa4055323cbec1cde4c2cb6b68398c upstream. cmdline_find_option_bool() keeps track of position in two strings: 1. the command-line 2. the option we are searchign for in the command-line We plow through each character in the command-line one at a time, always moving forward. We move forward in the option ('opptr') when we match characters in 'cmdline'. We reset the 'opptr' only when we go in to the 'st_wordstart' state. But, if we fail to match an option because we see a space (state=st_wordcmp, *opptr='\0',c=' '), we set state='st_wordskip' and 'break', moving to the next character. But, that move to the next character is the one *after* the ' '. This means that we will miss a 'st_wordstart' state. For instance, if we have cmdline = "foo fool"; and are searching for "fool", we have: "fool" opptr = ----^ "foo fool" c = --------^ We see that 'l' != ' ', set state=st_wordskip, break, and then move 'c', so: "foo fool" c = ---------^ and are still in state=st_wordskip. We will stay in wordskip until we have skipped "fool", thus missing the option we were looking for. This *only* happens when you have a partially- matching word followed by a matching one. To fix this, we always fall *into* the 'st_wordskip' state when we set it. Signed-off-by: Dave Hansen Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: fenghua.yu@intel.com Cc: yu-cheng.yu@intel.com Link: http://lkml.kernel.org/r/20151222225239.8E1DCA58@viggo.jf.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed