lkml.org 
[lkml]   [2019]   [Jun]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] modules: fix BUG when load module with rodata=n
From
Date


On 2019/6/18 21:48, Jessica Yu wrote:
> +++ Yang Yingliang [17/06/19 14:59 +0800]:
>> When loading a module with rodata=n, it causes an executing
>> NX-protected page BUG.
>>
>> [ 32.379191] kernel tried to execute NX-protected page - exploit
>> attempt? (uid: 0)
>> [ 32.382917] BUG: unable to handle page fault for address:
>> ffffffffc0005000
>> [ 32.385947] #PF: supervisor instruction fetch in kernel mode
>> [ 32.387662] #PF: error_code(0x0011) - permissions violation
>> [ 32.389352] PGD 240c067 P4D 240c067 PUD 240e067 PMD 421a52067 PTE
>> 8000000421a53063
>> [ 32.391396] Oops: 0011 [#1] SMP PTI
>> [ 32.392478] CPU: 7 PID: 2697 Comm: insmod Tainted: G
>> O 5.2.0-rc5+ #202
>> [ 32.394588] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
>> BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
>> [ 32.398157] RIP: 0010:ko_test_init+0x0/0x1000 [ko_test]
>> [ 32.399662] Code: Bad RIP value.
>> [ 32.400621] RSP: 0018:ffffc900029f3ca8 EFLAGS: 00010246
>> [ 32.402171] RAX: 0000000000000000 RBX: 0000000000000000 RCX:
>> 0000000000000000
>> [ 32.404332] RDX: 00000000000004c7 RSI: 0000000000000cc0 RDI:
>> ffffffffc0005000
>> [ 32.406347] RBP: ffffffffc0005000 R08: ffff88842fbebc40 R09:
>> ffffffff810ede4a
>> [ 32.408392] R10: ffffea00108e3480 R11: 0000000000000000 R12:
>> ffff88842bee21a0
>> [ 32.410472] R13: 0000000000000001 R14: 0000000000000001 R15:
>> ffffc900029f3e78
>> [ 32.412609] FS: 00007fb4f0c0a700(0000) GS:ffff88842fbc0000(0000)
>> knlGS:0000000000000000
>> [ 32.414722] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [ 32.416290] CR2: ffffffffc0004fd6 CR3: 0000000421a90004 CR4:
>> 0000000000020ee0
>> [ 32.418471] Call Trace:
>> [ 32.419136] do_one_initcall+0x41/0x1df
>> [ 32.420199] ? _cond_resched+0x10/0x40
>> [ 32.421433] ? kmem_cache_alloc_trace+0x36/0x160
>> [ 32.422827] do_init_module+0x56/0x1f7
>> [ 32.423946] load_module+0x1e67/0x2580
>> [ 32.424947] ? __alloc_pages_nodemask+0x150/0x2c0
>> [ 32.426413] ? map_vm_area+0x2d/0x40
>> [ 32.427530] ? __vmalloc_node_range+0x1ef/0x260
>> [ 32.428850] ? __do_sys_init_module+0x135/0x170
>> [ 32.430060] ? _cond_resched+0x10/0x40
>> [ 32.431249] __do_sys_init_module+0x135/0x170
>> [ 32.432547] do_syscall_64+0x43/0x120
>> [ 32.433853] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>
>> Because if rodata=n, set_memory_x() cann't be called, fix this by
>> calling set_memory_x in complete_formation();
>>
>> Fixes: f2c65fb3221a ("x86/modules: Avoid breaking W^X while loading
>> modules")
>> Suggested-by: Jian Cheng <cj.chengjian@huawei.com>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>> kernel/module.c | 9 +++++++--
>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/module.c b/kernel/module.c
>> index 80c7c09584cf..1a5d879573c3 100644
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -1949,12 +1949,10 @@ void module_enable_ro(const struct module
>> *mod, bool after_init)
>> set_vm_flush_reset_perms(mod->core_layout.base);
>> set_vm_flush_reset_perms(mod->init_layout.base);
>> frob_text(&mod->core_layout, set_memory_ro);
>> - frob_text(&mod->core_layout, set_memory_x);
>>
>> frob_rodata(&mod->core_layout, set_memory_ro);
>>
>> frob_text(&mod->init_layout, set_memory_ro);
>> - frob_text(&mod->init_layout, set_memory_x);
>>
>> frob_rodata(&mod->init_layout, set_memory_ro);
>
> Just a style-related nit: could you also please shrink down this chunk
> and remove the empty lines between the frob_* calls?
OK,I will do it in next version.

>
>> @@ -2018,6 +2016,12 @@ void set_all_modules_text_ro(void)
>> static void module_enable_nx(const struct module *mod) { }
>> #endif
>
> And note that we will need a stub for module_enable_x() here as well.
module_enable_x() is outside of CONFIG_STRICT_MODULE_RWX.

>
> Thanks!
>
> Jessica
>
>
> .
>


\
 
 \ /
  Last update: 2019-06-19 04:29    [W:0.081 / U:2.832 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site