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321d628a FG |
1 | From df469cffe07c84906be43e89d33f2a8a5312e60f Mon Sep 17 00:00:00 2001 |
2 | From: Andi Kleen <ak@linux.intel.com> | |
3 | Date: Fri, 13 Oct 2017 14:56:43 -0700 | |
e4cdf2a5 | 4 | Subject: [PATCH 067/241] x86/fpu: Parse clearcpuid= as early XSAVE argument |
321d628a FG |
5 | MIME-Version: 1.0 |
6 | Content-Type: text/plain; charset=UTF-8 | |
7 | Content-Transfer-Encoding: 8bit | |
8 | ||
9 | CVE-2017-5754 | |
10 | ||
11 | With a followon patch we want to make clearcpuid affect the XSAVE | |
12 | configuration. But xsave is currently initialized before arguments | |
13 | are parsed. Move the clearcpuid= parsing into the special | |
14 | early xsave argument parsing code. | |
15 | ||
16 | Since clearcpuid= contains a = we need to keep the old __setup | |
17 | around as a dummy, otherwise it would end up as a environment | |
18 | variable in init's environment. | |
19 | ||
20 | Signed-off-by: Andi Kleen <ak@linux.intel.com> | |
21 | Reviewed-by: Thomas Gleixner <tglx@linutronix.de> | |
22 | Cc: Linus Torvalds <torvalds@linux-foundation.org> | |
23 | Cc: Peter Zijlstra <peterz@infradead.org> | |
24 | Link: http://lkml.kernel.org/r/20171013215645.23166-4-andi@firstfloor.org | |
25 | Signed-off-by: Ingo Molnar <mingo@kernel.org> | |
26 | (cherry picked from commit 0c2a3913d6f50503f7c59d83a6219e39508cc898) | |
27 | Signed-off-by: Andy Whitcroft <apw@canonical.com> | |
28 | Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> | |
29 | (cherry picked from commit 27deb452eb0d27c406f3817ab057201aa8767abe) | |
30 | Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> | |
31 | --- | |
32 | arch/x86/kernel/cpu/common.c | 16 +++++++--------- | |
33 | arch/x86/kernel/fpu/init.c | 11 +++++++++++ | |
34 | 2 files changed, 18 insertions(+), 9 deletions(-) | |
35 | ||
36 | diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c | |
37 | index 4be7b209a3d6..ef7b1ba56363 100644 | |
38 | --- a/arch/x86/kernel/cpu/common.c | |
39 | +++ b/arch/x86/kernel/cpu/common.c | |
40 | @@ -1293,18 +1293,16 @@ void print_cpu_info(struct cpuinfo_x86 *c) | |
41 | pr_cont(")\n"); | |
42 | } | |
43 | ||
44 | -static __init int setup_disablecpuid(char *arg) | |
45 | +/* | |
46 | + * clearcpuid= was already parsed in fpu__init_parse_early_param. | |
47 | + * But we need to keep a dummy __setup around otherwise it would | |
48 | + * show up as an environment variable for init. | |
49 | + */ | |
50 | +static __init int setup_clearcpuid(char *arg) | |
51 | { | |
52 | - int bit; | |
53 | - | |
54 | - if (get_option(&arg, &bit) && bit >= 0 && bit < NCAPINTS * 32) | |
55 | - setup_clear_cpu_cap(bit); | |
56 | - else | |
57 | - return 0; | |
58 | - | |
59 | return 1; | |
60 | } | |
61 | -__setup("clearcpuid=", setup_disablecpuid); | |
62 | +__setup("clearcpuid=", setup_clearcpuid); | |
63 | ||
64 | #ifdef CONFIG_X86_64 | |
65 | struct desc_ptr idt_descr __ro_after_init = { | |
66 | diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c | |
67 | index d5d44c452624..07f0ab877f49 100644 | |
68 | --- a/arch/x86/kernel/fpu/init.c | |
69 | +++ b/arch/x86/kernel/fpu/init.c | |
70 | @@ -249,6 +249,10 @@ static void __init fpu__init_system_ctx_switch(void) | |
71 | */ | |
72 | static void __init fpu__init_parse_early_param(void) | |
73 | { | |
74 | + char arg[32]; | |
75 | + char *argptr = arg; | |
76 | + int bit; | |
77 | + | |
78 | if (cmdline_find_option_bool(boot_command_line, "no387")) | |
79 | setup_clear_cpu_cap(X86_FEATURE_FPU); | |
80 | ||
81 | @@ -266,6 +270,13 @@ static void __init fpu__init_parse_early_param(void) | |
82 | ||
83 | if (cmdline_find_option_bool(boot_command_line, "noxsaves")) | |
84 | setup_clear_cpu_cap(X86_FEATURE_XSAVES); | |
85 | + | |
86 | + if (cmdline_find_option(boot_command_line, "clearcpuid", arg, | |
87 | + sizeof(arg)) && | |
88 | + get_option(&argptr, &bit) && | |
89 | + bit >= 0 && | |
90 | + bit < NCAPINTS * 32) | |
91 | + setup_clear_cpu_cap(bit); | |
92 | } | |
93 | ||
94 | /* | |
95 | -- | |
96 | 2.14.2 | |
97 |