RE: [linux-next:master 2476/12912] security/integrity/ima/ima_crypto.c:575:12: warning: stack frame size of 1152 bytes in function 'ima_calc_field_array_hash_tfm'

From: kbuild test robot [mailto:lkp@intel.com]
security/integrity/ima/ima_crypto.c:575:12: warning: stack frame size of
1152 bytes in function 'ima_calc_field_array_hash_tfm'

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
master
head:   b0523c7b1c9d0edcd6c0fe6d2cb558a9ad5c60a8
commit: 1ea973df6e2166d1a576cabe5d08925d3261ff9d [2476/12912] ima:
Calculate and extend PCR with digests in ima_template_entry
config: mips-randconfig-r012-20200526 (attached as .config)
compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project
3393cc4cebf9969db94dc424b7a2b6195589c33b)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-
tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        git checkout 1ea973df6e2166d1a576cabe5d08925d3261ff9d
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross
ARCH=mips

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <redacted>

All warnings (new ones prefixed by >>, old ones prefixed by <<):

quoted

quoted

security/integrity/ima/ima_crypto.c:575:12: warning: stack frame size of

1152 bytes in function 'ima_calc_field_array_hash_tfm' [-Wframe-larger-
than=]
static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
^
1 warning generated.

It seems that the problem is caused by the definition of
 SHASH_DESC_ON_STACK:

+#define SHASH_DESC_ON_STACK(shash, ctx)                                  \
+       char __##shash##_desc[sizeof(struct shash_desc) +         \
+               crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \

CRYPTO_MINALIGN_ATTR is equal to __attribute__ ((__aligned__(128))).

It is defined in include/linux/crypto.h:

#define CRYPTO_MINALIGN ARCH_KMALLOC_MINALIGN

#define CRYPTO_MINALIGN_ATTR __attribute__ ((__aligned__(CRYPTO_MINALIGN)))


I found in include/linux/slab.h:

#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
#else
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
#endif

If I set ARCH_KMALLOC_MINALIGN to __alignof__(unsigned long long)
the warning message disappears.

Herbert, can you please have a look?

Thanks

Roberto

HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Li Peng, Li Jian, Shi Yanli

vim +/ima_calc_field_array_hash_tfm +575
security/integrity/ima/ima_crypto.c

3bcced39ea7d1b0 Dmitry Kasatkin 2014-02-26  571
3323eec921efd81 Mimi Zohar      2009-02-04  572  /*
a71dc65d30a4724 Roberto Sassu   2013-06-07  573   * Calculate the hash of
template data
3323eec921efd81 Mimi Zohar      2009-02-04  574   */
a71dc65d30a4724 Roberto Sassu   2013-06-07 @575  static int
ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
7ca79645a1f8837 Roberto Sassu   2020-03-25  576
		 struct ima_template_entry *entry,
6d94809af6b0830 Roberto Sassu   2020-03-25  577
		 int tfm_idx)
3323eec921efd81 Mimi Zohar      2009-02-04  578  {
6d94809af6b0830 Roberto Sassu   2020-03-25  579
	SHASH_DESC_ON_STACK(shash, ima_algo_array[tfm_idx].tfm);
7ca79645a1f8837 Roberto Sassu   2020-03-25  580  	struct
ima_template_desc *td = entry->template_desc;
7ca79645a1f8837 Roberto Sassu   2020-03-25  581  	int num_fields =
entry->template_desc->num_fields;
a71dc65d30a4724 Roberto Sassu   2013-06-07  582  	int rc, i;
3323eec921efd81 Mimi Zohar      2009-02-04  583
6d94809af6b0830 Roberto Sassu   2020-03-25  584  	shash->tfm =
ima_algo_array[tfm_idx].tfm;
3323eec921efd81 Mimi Zohar      2009-02-04  585
357aabed626fe3f Behan Webster   2014-04-04  586  	rc =
crypto_shash_init(shash);
a71dc65d30a4724 Roberto Sassu   2013-06-07  587  	if (rc != 0)
a71dc65d30a4724 Roberto Sassu   2013-06-07  588  		return rc;
a71dc65d30a4724 Roberto Sassu   2013-06-07  589
a71dc65d30a4724 Roberto Sassu   2013-06-07  590  	for (i = 0; i <
num_fields; i++) {
e3b64c268b485f5 Roberto Sassu   2014-02-03  591  		u8
buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
e3b64c268b485f5 Roberto Sassu   2014-02-03  592  		u8
*data_to_hash = field_data[i].data;
e3b64c268b485f5 Roberto Sassu   2014-02-03  593  		u32 datalen
= field_data[i].len;
98e1d55d033eed2 Andreas Steffen 2016-12-19  594  		u32
datalen_to_hash =
98e1d55d033eed2 Andreas Steffen 2016-12-19  595
	    !ima_canonical_fmt ? datalen : cpu_to_le32(datalen);
e3b64c268b485f5 Roberto Sassu   2014-02-03  596
b6f8f16f41d9286 Roberto Sassu   2013-11-08  597  		if
(strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
357aabed626fe3f Behan Webster   2014-04-04  598  			rc =
crypto_shash_update(shash,
98e1d55d033eed2 Andreas Steffen 2016-12-19  599
			(const u8 *) &datalen_to_hash,
98e1d55d033eed2 Andreas Steffen 2016-12-19  600
			sizeof(datalen_to_hash));
b6f8f16f41d9286 Roberto Sassu   2013-11-08  601  			if (rc)
b6f8f16f41d9286 Roberto Sassu   2013-11-08  602
	break;
e3b64c268b485f5 Roberto Sassu   2014-02-03  603  		} else if
(strcmp(td->fields[i]->field_id, "n") == 0) {
e3b64c268b485f5 Roberto Sassu   2014-02-03  604
	memcpy(buffer, data_to_hash, datalen);
e3b64c268b485f5 Roberto Sassu   2014-02-03  605
	data_to_hash = buffer;
e3b64c268b485f5 Roberto Sassu   2014-02-03  606
	datalen = IMA_EVENT_NAME_LEN_MAX + 1;
b6f8f16f41d9286 Roberto Sassu   2013-11-08  607  		}
357aabed626fe3f Behan Webster   2014-04-04  608  		rc =
crypto_shash_update(shash, data_to_hash, datalen);
a71dc65d30a4724 Roberto Sassu   2013-06-07  609  		if (rc)
a71dc65d30a4724 Roberto Sassu   2013-06-07  610
	break;
a71dc65d30a4724 Roberto Sassu   2013-06-07  611  	}
a71dc65d30a4724 Roberto Sassu   2013-06-07  612
a71dc65d30a4724 Roberto Sassu   2013-06-07  613  	if (!rc)
6d94809af6b0830 Roberto Sassu   2020-03-25  614  		rc =
crypto_shash_final(shash, entry->digests[tfm_idx].digest);
a71dc65d30a4724 Roberto Sassu   2013-06-07  615
a71dc65d30a4724 Roberto Sassu   2013-06-07  616  	return rc;
3323eec921efd81 Mimi Zohar      2009-02-04  617  }
3323eec921efd81 Mimi Zohar      2009-02-04  618

:::::: The code at line 575 was first introduced by commit
:::::: a71dc65d30a472409f05d247f4eab91b14acf2f5 ima: switch to new
template management mechanism

:::::: TO: Roberto Sassu [off-list ref]
:::::: CC: Mimi Zohar [off-list ref]

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