[Crash-utility] [PATCH v3] Basic support for PaX's split module layout
lijiang
lijiang at redhat.com
Thu Sep 3 01:42:39 UTC 2020
在 2020年09月03日 07:43, HAGIO KAZUHITO(萩尾 一仁) 写道:
> Hi Lianbo,
>
> -----Original Message-----
>> Does this need further input from my site to get merged? Lianbo acked an
>> earlier version[1], so this should be fine as is?
>
Sorry for the delay. Thanks for your patch, Mathias.
> as you commented after the ack, I thought you would check the new version
> again. Can I merge the v3 patch?
>
Sure. The v3 looks good.
Acked-by: Lianbo Jiang <lijiang at redhat.com>
Thanks.
Lianbo
> Thanks,
> Kazu
>
>>
>> Thanks,
>> Mathias
>>
>> [1] https://www.redhat.com/archives/crash-utility/2020-August/msg00021.html
>>
>> Am 25.08.20 um 04:09 schrieb HAGIO KAZUHITO(萩尾 一仁):
>>> -----Original Message-----
>>>> PaX and grsecurity kernels split module memory into dedicated r/x and
>>>> r/w mappings using '*_rw' and '*_rx' named member variables in 'struct
>>>> module'. To add basic support for such kernels detect the split layout
>>>> by testing for the corresponding structure members and use these
>>>> instead.
>>>>
>>>> So far we limit ourself to only track module code mappings for such
>>>> kernels as adding support for separate data mappings violates lots of
>>>> invariants in the rest of our code base, thereby would require a major
>>>> rework. However, with that patch applied, module code references can be
>>>> resolved in backtraces, memory and code dumps, which makes it already
>>>> very useful for analyzing such kernels.
>>>>
>>>> Signed-off-by: Mathias Krause <minipli at grsecurity.net>
>>>> ---
>>>> v3:
>>>> - dump offsets unconditional
>>>> - fix indention of 'module_init_size' offset dump
>>>
>>> Thanks for the update. The v3 patch looks good to me.
>>>
>>> Acked-by: Kazuhito Hagio <k-hagio-ab at nec.com>
>>>
>>> Thanks,
>>> Kazu
>>>
>>>>
>>>> v2:
>>>> - add members to end of struct offset_table
>>>> - add offsets to dump_offset_table()
>>>>
>>>> defs.h | 13 +++++++++++
>>>> kernel.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++----
>>>> symbols.c | 38 ++++++++++++++++++++++---------
>>>> 3 files changed, 103 insertions(+), 16 deletions(-)
>>>>
>>>> diff --git a/defs.h b/defs.h
>>>> index 17e98763362b..ae860448ab15 100644
>>>> --- a/defs.h
>>>> +++ b/defs.h
>>>> @@ -654,12 +654,15 @@ struct new_utsname {
>>>> #define TIMER_BASES (0x20ULL)
>>>> #define IRQ_DESC_TREE_RADIX (0x40ULL)
>>>> #define IRQ_DESC_TREE_XARRAY (0x80ULL)
>>>> +#define KMOD_PAX (0x100ULL)
>>>>
>>>> #define XEN() (kt->flags & ARCH_XEN)
>>>> #define OPENVZ() (kt->flags & ARCH_OPENVZ)
>>>> #define PVOPS() (kt->flags & ARCH_PVOPS)
>>>> #define PVOPS_XEN() (kt->flags & ARCH_PVOPS_XEN)
>>>>
>>>> +#define PAX_MODULE_SPLIT() (kt->flags2 & KMOD_PAX)
>>>> +
>>>> #define XEN_MACHINE_TO_MFN(m) ((ulonglong)(m) >> PAGESHIFT())
>>>> #define XEN_PFN_TO_PSEUDO(p) ((ulonglong)(p) << PAGESHIFT())
>>>>
>>>> @@ -2089,6 +2092,14 @@ struct offset_table { /* stash of commonly-used offsets */
>>>> long size_class_size;
>>>> long gendisk_private_data;
>>>> long zram_table_entry;
>>>> + long module_core_size_rw;
>>>> + long module_core_size_rx;
>>>> + long module_init_size_rw;
>>>> + long module_init_size_rx;
>>>> + long module_module_core_rw;
>>>> + long module_module_core_rx;
>>>> + long module_module_init_rw;
>>>> + long module_module_init_rx;
>>>> };
>>>>
>>>> struct size_table { /* stash of commonly-used sizes */
>>>> @@ -2313,6 +2324,8 @@ struct array_table {
>>>> * in the offset table, size table or array_table.
>>>> */
>>>> #define OFFSET(X) (OFFSET_verify(offset_table.X, (char *)__FUNCTION__, __FILE__, __LINE__,
>> #X))
>>>> +#define MODULE_OFFSET(X,Y) (PAX_MODULE_SPLIT() ? OFFSET(Y) : OFFSET(X))
>>>> +#define MODULE_OFFSET2(X,T) MODULE_OFFSET(X, X##_##T)
>>>> #define SIZE(X) (SIZE_verify(size_table.X, (char *)__FUNCTION__, __FILE__, __LINE__, #X))
>>>> #define INVALID_OFFSET (-1)
>>>> #define INVALID_MEMBER(X) (offset_table.X == INVALID_OFFSET)
>>>> diff --git a/kernel.c b/kernel.c
>>>> index f179375f2d3d..f0268adccd4a 100644
>>>> --- a/kernel.c
>>>> +++ b/kernel.c
>>>> @@ -3540,6 +3540,62 @@ module_init(void)
>>>> "module_core");
>>>> MEMBER_OFFSET_INIT(module_module_init, "module",
>>>> "module_init");
>>>> + } else if (MEMBER_EXISTS("module", "module_core_rx")) {
>>>> + if (CRASHDEBUG(1))
>>>> + error(INFO, "PaX module layout detected.\n");
>>>> + kt->flags2 |= KMOD_PAX;
>>>> +
>>>> + MEMBER_OFFSET_INIT(module_core_size_rw, "module",
>>>> + "core_size_rw");
>>>> + MEMBER_OFFSET_INIT(module_core_size_rx, "module",
>>>> + "core_size_rx");
>>>> +
>>>> + MEMBER_OFFSET_INIT(module_init_size_rw, "module",
>>>> + "init_size_rw");
>>>> + MEMBER_OFFSET_INIT(module_init_size_rx, "module",
>>>> + "init_size_rx");
>>>> +
>>>> + MEMBER_OFFSET_INIT(module_module_core_rw, "module",
>>>> + "module_core_rw");
>>>> + MEMBER_OFFSET_INIT(module_module_core_rx, "module",
>>>> + "module_core_rx");
>>>> +
>>>> + MEMBER_OFFSET_INIT(module_module_init_rw, "module",
>>>> + "module_init_rw");
>>>> + MEMBER_OFFSET_INIT(module_module_init_rx, "module",
>>>> + "module_init_rx");
>>>> + } else if (MEMBER_EXISTS("module_layout", "base_rx")) {
>>>> + if (CRASHDEBUG(1))
>>>> + error(INFO, "PaX module layout detected.\n");
>>>> + kt->flags2 |= KMOD_PAX;
>>>> +
>>>> + ASSIGN_OFFSET(module_core_size_rw) =
>>>> + MEMBER_OFFSET("module", "core_layout") +
>>>> + MEMBER_OFFSET("module_layout", "size_rw");
>>>> + ASSIGN_OFFSET(module_core_size_rx) =
>>>> + MEMBER_OFFSET("module", "core_layout") +
>>>> + MEMBER_OFFSET("module_layout", "size_rx");
>>>> +
>>>> + ASSIGN_OFFSET(module_init_size_rw) =
>>>> + MEMBER_OFFSET("module", "init_layout") +
>>>> + MEMBER_OFFSET("module_layout", "size_rw");
>>>> + ASSIGN_OFFSET(module_init_size_rx) =
>>>> + MEMBER_OFFSET("module", "init_layout") +
>>>> + MEMBER_OFFSET("module_layout", "size_rx");
>>>> +
>>>> + ASSIGN_OFFSET(module_module_core_rw) =
>>>> + MEMBER_OFFSET("module", "core_layout") +
>>>> + MEMBER_OFFSET("module_layout", "base_rw");
>>>> + ASSIGN_OFFSET(module_module_core_rx) =
>>>> + MEMBER_OFFSET("module", "core_layout") +
>>>> + MEMBER_OFFSET("module_layout", "base_rx");
>>>> +
>>>> + ASSIGN_OFFSET(module_module_init_rw) =
>>>> + MEMBER_OFFSET("module", "init_layout") +
>>>> + MEMBER_OFFSET("module_layout", "base_rw");
>>>> + ASSIGN_OFFSET(module_module_init_rx) =
>>>> + MEMBER_OFFSET("module", "init_layout") +
>>>> + MEMBER_OFFSET("module_layout", "base_rx");
>>>> } else {
>>>> ASSIGN_OFFSET(module_core_size) =
>>>> MEMBER_OFFSET("module", "core_layout") +
>>>> @@ -3682,10 +3738,10 @@ module_init(void)
>>>> case KALLSYMS_V2:
>>>> if (THIS_KERNEL_VERSION >= LINUX(2,6,27)) {
>>>> numksyms = UINT(modbuf + OFFSET(module_num_symtab));
>>>> - size = UINT(modbuf + OFFSET(module_core_size));
>>>> + size = UINT(modbuf + MODULE_OFFSET2(module_core_size, rx));
>>>> } else {
>>>> numksyms = ULONG(modbuf + OFFSET(module_num_symtab));
>>>> - size = ULONG(modbuf + OFFSET(module_core_size));
>>>> + size = ULONG(modbuf + MODULE_OFFSET2(module_core_size, rx));
>>>> }
>>>>
>>>> if (!size) {
>>>> @@ -3792,7 +3848,7 @@ verify_modules(void)
>>>> break;
>>>> case KMOD_V2:
>>>> mod_base = ULONG(modbuf +
>>>> - OFFSET(module_module_core));
>>>> + MODULE_OFFSET2(module_module_core, rx));
>>>> break;
>>>> }
>>>>
>>>> @@ -3816,10 +3872,10 @@ verify_modules(void)
>>>> OFFSET(module_name);
>>>> if (THIS_KERNEL_VERSION >= LINUX(2,6,27))
>>>> mod_size = UINT(modbuf +
>>>> - OFFSET(module_core_size));
>>>> + MODULE_OFFSET2(module_core_size, rx));
>>>> else
>>>> mod_size = ULONG(modbuf +
>>>> - OFFSET(module_core_size));
>>>> + MODULE_OFFSET2(module_core_size, rx));
>>>> if (strlen(module_name) < MAX_MOD_NAME)
>>>> strcpy(buf, module_name);
>>>> else
>>>> @@ -5997,6 +6053,8 @@ dump_kernel_table(int verbose)
>>>> fprintf(fp, "%sIRQ_DESC_TREE_RADIX", others++ ? "|" : "");
>>>> if (kt->flags2 & IRQ_DESC_TREE_XARRAY)
>>>> fprintf(fp, "%sIRQ_DESC_TREE_XARRAY", others++ ? "|" : "");
>>>> + if (kt->flags2 & KMOD_PAX)
>>>> + fprintf(fp, "%sKMOD_PAX", others++ ? "|" : "");
>>>> fprintf(fp, ")\n");
>>>>
>>>> fprintf(fp, " stext: %lx\n", kt->stext);
>>>> diff --git a/symbols.c b/symbols.c
>>>> index 2fecaee093a2..311fdb7df29e 100644
>>>> --- a/symbols.c
>>>> +++ b/symbols.c
>>>> @@ -1766,17 +1766,17 @@ store_module_symbols_v2(ulong total, int mods_installed)
>>>>
>>>> if (THIS_KERNEL_VERSION >= LINUX(2,6,27)) {
>>>> nksyms = UINT(modbuf + OFFSET(module_num_symtab));
>>>> - size = UINT(modbuf + OFFSET(module_core_size));
>>>> + size = UINT(modbuf + MODULE_OFFSET2(module_core_size, rx));
>>>> } else {
>>>> nksyms = ULONG(modbuf + OFFSET(module_num_symtab));
>>>> - size = ULONG(modbuf + OFFSET(module_core_size));
>>>> + size = ULONG(modbuf + MODULE_OFFSET2(module_core_size, rx));
>>>> }
>>>>
>>>> mod_name = modbuf + OFFSET(module_name);
>>>>
>>>> lm = &st->load_modules[m++];
>>>> BZERO(lm, sizeof(struct load_module));
>>>> - lm->mod_base = ULONG(modbuf + OFFSET(module_module_core));
>>>> + lm->mod_base = ULONG(modbuf + MODULE_OFFSET2(module_module_core, rx));
>>>> lm->module_struct = mod;
>>>> lm->mod_size = size;
>>>> if (strlen(mod_name) < MAX_MOD_NAME)
>>>> @@ -1795,23 +1795,23 @@ store_module_symbols_v2(ulong total, int mods_installed)
>>>> lm->mod_flags = MOD_EXT_SYMS;
>>>> lm->mod_ext_symcnt = mcnt;
>>>> lm->mod_init_module_ptr = ULONG(modbuf +
>>>> - OFFSET(module_module_init));
>>>> + MODULE_OFFSET2(module_module_init, rx));
>>>> if (VALID_MEMBER(module_percpu))
>>>> lm->mod_percpu = ULONG(modbuf + OFFSET(module_percpu));
>>>> if (THIS_KERNEL_VERSION >= LINUX(2,6,27)) {
>>>> lm->mod_etext_guess = lm->mod_base +
>>>> - UINT(modbuf + OFFSET(module_core_text_size));
>>>> + UINT(modbuf + MODULE_OFFSET(module_core_text_size, module_core_size_rx));
>>>> lm->mod_init_size =
>>>> - UINT(modbuf + OFFSET(module_init_size));
>>>> + UINT(modbuf + MODULE_OFFSET2(module_init_size, rx));
>>>> lm->mod_init_text_size =
>>>> - UINT(modbuf + OFFSET(module_init_text_size));
>>>> + UINT(modbuf + MODULE_OFFSET(module_init_text_size, module_init_size_rx));
>>>> } else {
>>>> lm->mod_etext_guess = lm->mod_base +
>>>> - ULONG(modbuf + OFFSET(module_core_text_size));
>>>> + ULONG(modbuf + MODULE_OFFSET(module_core_text_size, module_core_size_rx));
>>>> lm->mod_init_size =
>>>> - ULONG(modbuf + OFFSET(module_init_size));
>>>> + ULONG(modbuf + MODULE_OFFSET2(module_init_size, rx));
>>>> lm->mod_init_text_size =
>>>> - ULONG(modbuf + OFFSET(module_init_text_size));
>>>> + ULONG(modbuf + MODULE_OFFSET(module_init_text_size, module_init_size_rx));
>>>> }
>>>> lm->mod_text_start = lm->mod_base;
>>>>
>>>> @@ -9119,12 +9119,28 @@ dump_offset_table(char *spec, ulong makestruct)
>>>> OFFSET(module_core_size));
>>>> fprintf(fp, " module_core_text_size: %ld\n",
>>>> OFFSET(module_core_text_size));
>>>> - fprintf(fp, " module_init_size: %ld\n",
>>>> + fprintf(fp, " module_init_size: %ld\n",
>>>> OFFSET(module_init_size));
>>>> fprintf(fp, " module_init_text_size: %ld\n",
>>>> OFFSET(module_init_text_size));
>>>> fprintf(fp, " module_module_init: %ld\n",
>>>> OFFSET(module_module_init));
>>>> + fprintf(fp, " module_module_core_rx: %ld\n",
>>>> + OFFSET(module_module_core_rx));
>>>> + fprintf(fp, " module_module_core_rw: %ld\n",
>>>> + OFFSET(module_module_core_rw));
>>>> + fprintf(fp, " module_core_size_rx: %ld\n",
>>>> + OFFSET(module_core_size_rx));
>>>> + fprintf(fp, " module_core_size_rw: %ld\n",
>>>> + OFFSET(module_core_size_rw));
>>>> + fprintf(fp, " module_module_init_rx: %ld\n",
>>>> + OFFSET(module_module_init_rx));
>>>> + fprintf(fp, " module_module_init_rw: %ld\n",
>>>> + OFFSET(module_module_init_rw));
>>>> + fprintf(fp, " module_init_size_rx: %ld\n",
>>>> + OFFSET(module_init_size_rx));
>>>> + fprintf(fp, " module_init_size_rw: %ld\n",
>>>> + OFFSET(module_init_size_rw));
>>>> fprintf(fp, " module_num_symtab: %ld\n",
>>>> OFFSET(module_num_symtab));
>>>> fprintf(fp, " module_symtab: %ld\n",
>>>> --
>>>> 2.20.1
>>>>
>>>>
>>>> --
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>>>> Crash-utility at redhat.com
>>>> https://www.redhat.com/mailman/listinfo/crash-utility
>>>
>>>
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