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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?xp9NVgGXR9FlqHlaoHaIOoUaRgQQ0iHu/dUS9cXxptNqw8+Psn4iIglJkasT?= =?us-ascii?Q?YefeQSLDOcHNOgz0alTVMS1Ve3ta1IiAmYCqUvlwvto5KQlF4X7M+fll+nCh?= =?us-ascii?Q?T+cFoL82jDxCASFm3u1v1lQDtjcM82SmYj2yexkYC2RQf11yMq4VFLDXJ1KQ?= =?us-ascii?Q?MB4TK+alIUdaH83jXDDKdVpjuQP7DJD4spuDrsGlh8Ho7wICIAyvzbcCnvcP?= =?us-ascii?Q?bMz7j14PJMwcZ7rspsNaMWck2920unvWiKPR/DuuCLxPYmU1N7ng3DsQZG1B?= =?us-ascii?Q?/Et66srIo9oUOhN6MpQEKMjOC0z3DPQ0TdflYhSrZ4WwAPr2tUamQImoIFoz?= =?us-ascii?Q?Eubvuu+2GwTLIQrSFNnfPZemVd6zpxhKeL1CSs/CBmk51Lf7rs19++4bwQU1?= =?us-ascii?Q?jnAQJVz1ODFyP2u0uQW4FWC0zy+4D5A78QX1C4ox4We9NS/g2oQsZJ0WElza?= =?us-ascii?Q?sBeBzYJol8J7ZEnEzI8+CX6tdtUBsAvzmQHF2VRqUkEzUxVmLX4DQjRSU5xm?= =?us-ascii?Q?ZqJ9V/2obxAN+7QNap+jrwNesXNWe/QfKYGw8R1Bc6LInes882X8biLRvoaX?= =?us-ascii?Q?P16GCvdufmRgb+n+W3yylaV3kxJ9ewaiKAE99IBVmmbLuiEHwp+wDAX3qWvl?= =?us-ascii?Q?ItYby639Bxmditq5FMWt6CLDDJOI33BC2l4l+b5Yy7Q9bI2dwDSQlzRvCh6C?= =?us-ascii?Q?WE23FFO0CfKStulqU0mL937iuzVLEeLJPMr5vfRLMf5lpwowM0Az8jlE2m4Y?= =?us-ascii?Q?d8Z2kYBY8OWl7Lu5uCcrlaBs39sWFjXCiVhZW5B8FywiL2Ep9/9HC1I/sYOI?= =?us-ascii?Q?1CwFlujC1OcRL8u2CkI4IAWF/N9YW7VLXWg6OzejSo64PiXEXPzebpIVBtcT?= =?us-ascii?Q?Z5WOMr+zdWcunm5f63NF3oerMLKre5PImU+h7Sk+barQ4l1YXXsXcLP+mrKo?= =?us-ascii?Q?3VFQ3FwioaudAMfALf7geDvzmI7Lb4y14V6yc750YczheUS59XyQ8/Hw5aJG?= =?us-ascii?Q?hpmUlCBXr1FXSfg/Yr0GgpGNA/HYZo01X8C+phElTv/PrrKhPe4BL0OVxGQb?= =?us-ascii?Q?xtmnrJgcDIZCLiNNu5LFysJM9bOCSRT1clM+J2BTfq4pPlcHp4uL5nPPdV7E?= =?us-ascii?Q?a20Eb5Fiv2sGAA5M13C98naK+WElOpEwUG+HPjcgAf0geC0/VSiOF9ubb8UB?= =?us-ascii?Q?bRvEHC9ngQSpZcifqZ936HgGxBH9hmcMjX2P5uPqLn0fqNqBtpp76x0EMNpB?= =?us-ascii?Q?yb13iH7XFNorSxBFvSqYzAT0B+u1kus9nzSk1BhsJVkvsJd45MVWQxy7fm4E?= =?us-ascii?Q?dX8wgLXkSybqq8xV/KvgogRPiZKEZerDwhaT3tHF67LEGKB+yzEun/2HVawI?= =?us-ascii?Q?IdOw9RFod7wHe9J2eIwG+CUrhTuBJrFl/6eaCxxt6gh4rxq4E3ozJG2J7zeQ?= =?us-ascii?Q?pvphbVe8ZKq84H4k5JbNzVDmarEqpSKxkuRV5qOYOMUK13hfyM100hpmuN70?= =?us-ascii?Q?4gmsC5NiJU0llpoJ4kZ8TrXJY0RhlUlY+7o1Uf7GgcI+Zj1SJvuE1xL9aSJm?= =?us-ascii?Q?nkJHswfMlJ3b+5EcM1rYksJ2aMywpiTIZ15bBLZB?= X-MS-Exchange-CrossTenant-Network-Message-Id: e4b3ab60-46ec-4f97-a333-08dac3bf5686 X-MS-Exchange-CrossTenant-AuthSource: MN0PR11MB6304.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Nov 2022 08:32:59.9972 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 5ccFgd5oJm9uqkEauj9Ac4ZHocn1Vw46RsU1glAdT/vl7uSqGo4ZfQ52vMNy2e9YLSMr7XDKjuxVAebb+ixx5A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR11MB4599 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 11, 2022 at 04:16:32PM +0800, Vlastimil Babka wrote: > On 10/21/22 05:24, Feng Tang wrote: > > kmalloc's API family is critical for mm, and one of its nature is that > > it will round up the request size to a fixed one (mostly power of 2). > > When user requests memory for '2^n + 1' bytes, actually 2^(n+1) bytes > > could be allocated, so there is an extra space than what is originally > > requested. > > > > This patchset tries to extend the redzone sanity check to the extra > > kmalloced buffer than requested, to better detect un-legitimate access > > to it. (dependson SLAB_STORE_USER & SLAB_RED_ZONE) > > > > The redzone part has been tested with code below: > > > > for (shift = 3; shift <= 12; shift++) { > > size = 1 << shift; > > buf = kmalloc(size + 4, GFP_KERNEL); > > /* We have 96, 196 kmalloc size, which is not power of 2 */ > > if (size == 64 || size == 128) > > oob_size = 16; > > else > > oob_size = size - 4; > > memset(buf + size + 4, 0xee, oob_size); > > kfree(buf); > > } > > Sounds like a new slub_kunit test would be useful? :) doesn't need to be > that exhaustive wrt all sizes, we could just pick one and check that a write > beyond requested kmalloc size is detected? Just git-grepped out slub_kunit.c :), will try to add a case to it. I'll also check if the case will also be caught by other sanitizer tools like kasan/kfence etc. Thanks, Feng > Thanks! >