Re: [v3 PATCH 7/8] crypto: scomp - Remove support for most non-trivial destination SG lists

[Dan Carpenter <dan.carpenter@linaro.org>]

Hi Herbert,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Herbert-Xu/crypto-api-Add-cra_type-destroy-hook/20250309-104526
base:   https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master
patch link:    https://lore.kernel.org/r/205f05023b5ff0d8cf7deb6e0a5fbb4643f02e00.1741488107.git.herbert%40gondor.apana.org.au
patch subject: [v3 PATCH 7/8] crypto: scomp - Remove support for most non-trivial destination SG lists
config: um-randconfig-r072-20250310 (https://download.01.org/0day-ci/archive/20250311/202503110237.GjZvyi0K-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project e15545cad8297ec7555f26e5ae74a9f0511203e7)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202503110237.GjZvyi0K-lkp@intel.com/

New smatch warnings:
crypto/scompress.c:180 scomp_acomp_comp_decomp() error: we previously assumed 'req->dst' could be null (see line 174)

vim +180 crypto/scompress.c

1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  159  static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  160  {
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  161  	struct crypto_acomp *tfm = crypto_acomp_reqtfm(req);
5b855462cc7e3f3 Herbert Xu                2025-03-09  162  	struct crypto_scomp **tfm_ctx = acomp_tfm_ctx(tfm);
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  163  	struct crypto_scomp *scomp = *tfm_ctx;
e77b9947333baa6 Herbert Xu                2025-03-09  164  	struct crypto_acomp_stream *stream;
71052dcf4be70be Sebastian Andrzej Siewior 2019-03-29  165  	struct scomp_scratch *scratch;
5b855462cc7e3f3 Herbert Xu                2025-03-09  166  	unsigned int slen = req->slen;
5b855462cc7e3f3 Herbert Xu                2025-03-09  167  	unsigned int dlen = req->dlen;
77292bb8ca69c80 Barry Song                2024-03-02  168  	void *src, *dst;
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  169  	int ret;
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  170  
5b855462cc7e3f3 Herbert Xu                2025-03-09  171  	if (!req->src || !slen)
71052dcf4be70be Sebastian Andrzej Siewior 2019-03-29  172  		return -EINVAL;
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  173  
5b855462cc7e3f3 Herbert Xu                2025-03-09 @174  	if (req->dst && !dlen)
                                                                    ^^^^^^^^
Is this check necessary?

71052dcf4be70be Sebastian Andrzej Siewior 2019-03-29  175  		return -EINVAL;
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  176  
5b855462cc7e3f3 Herbert Xu                2025-03-09  177  	if (sg_nents(req->dst) > 1)
5b855462cc7e3f3 Herbert Xu                2025-03-09  178  		return -ENOSYS;
1ab53a77b772bf7 Giovanni Cabiddu          2016-10-21  179  
5b855462cc7e3f3 Herbert Xu                2025-03-09 @180  	if (req->dst->offset >= PAGE_SIZE)
                                                                    ^^^^^^^^^^
Unchecked dereference

5b855462cc7e3f3 Herbert Xu                2025-03-09  181  		return -ENOSYS;
744e1885922a994 Chengming Zhou            2023-12-27  182  
5b855462cc7e3f3 Herbert Xu                2025-03-09  183  	if (req->dst->offset + dlen > PAGE_SIZE)

-- 
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https://github.com/intel/lkp-tests/wiki