Messages in this thread Patch in this message | | | From | Qiuxu Zhuo <> | Subject | [PATCH 1/3] EDAC/igen6: Fix slab-use-after-free in igen6_unregister_mci() | Date | Sun, 8 Oct 2023 16:02:29 +0800 |
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When unloading the igen6_edac driver, the EDAC core wrongly kfreed 'pvt_info,' which was private data and managed by the igen6_edac driver. This resulted in a slab-use-after-free bug. Fix it by adding a flag to indicate whether 'pvt_info' is managed by the EDAC core. The EDAC core will only kfree 'pvt_info' when the flag is set to true.
BUG: KASAN: slab-use-after-free in igen6_unregister_mcis+0x74/0x1f0 [igen6_edac] Read of size 8 at addr ffff88810c10a350 by task modprobe/5137
Call Trace: <TASK> dump_stack_lvl+0x4c/0x70 print_report+0xcf/0x620 ? __virt_addr_valid+0xfc/0x180 ? kasan_complete_mode_report_info+0x80/0x210 ? igen6_unregister_mcis+0x74/0x1f0 [igen6_edac] kasan_report+0xbf/0x100 ? igen6_unregister_mcis+0x74/0x1f0 [igen6_edac] __asan_load8+0x82/0xb0 igen6_unregister_mcis+0x74/0x1f0 [igen6_edac] igen6_remove+0x97/0xc0 [igen6_edac] ... Allocated by task 578: kasan_save_stack+0x2a/0x50 kasan_set_track+0x29/0x40 kasan_save_alloc_info+0x1f/0x30 __kasan_kmalloc+0x88/0xa0 kmalloc_trace+0x4e/0xb0 igen6_probe+0xe5/0x1400 [igen6_edac] local_pci_probe+0x89/0xf0 pci_device_probe+0x18e/0x450 ... Freed by task 5137: kasan_save_stack+0x2a/0x50 kasan_set_track+0x29/0x40 kasan_save_free_info+0x32/0x50 __kasan_slab_free+0x113/0x1b0 slab_free_freelist_hook+0xb1/0x190 __kmem_cache_free+0x15d/0x280 kfree+0x7d/0x120 mci_release+0x24a/0x280 device_release+0x64/0x110 kobject_put+0xfd/0x260 put_device+0x17/0x30 edac_mc_free+0x43/0x50 igen6_unregister_mcis+0x18f/0x1f0 [igen6_edac] igen6_remove+0x97/0xc0 [igen6_edac] pci_device_remove+0x6a/0x100 device_remove+0x6f/0xb0
Fixes: 0bbb265f7089 ("EDAC/mc: Get rid of silly one-shot struct allocation in edac_mc_alloc()") Co-developed-by: Lili Li <lili.li@intel.com> Signed-off-by: Lili Li <lili.li@intel.com> Tested-by: Lili Li <lili.li@intel.com> Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> --- drivers/edac/edac_mc.c | 19 +++++++++++++++---- include/linux/edac.h | 5 +++++ 2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c index 6faeb2ab3960..6a68b0225130 100644 --- a/drivers/edac/edac_mc.c +++ b/drivers/edac/edac_mc.c @@ -201,7 +201,14 @@ static void mci_release(struct device *dev) } kfree(mci->csrows); } - kfree(mci->pvt_info); + + /* + * if !pvt_managed_by_edac_core, the resource, e.g. memory or MMIO-mapped + * registers pointed by pvt_info is managed by the EDAC driver. The EDAC + * core shouldn't kfree it. + */ + if (mci->pvt_managed_by_edac_core) + kfree(mci->pvt_info); kfree(mci->layers); kfree(mci); } @@ -369,9 +376,13 @@ struct mem_ctl_info *edac_mc_alloc(unsigned int mc_num, if (!mci->layers) goto error; - mci->pvt_info = kzalloc(sz_pvt, GFP_KERNEL); - if (!mci->pvt_info) - goto error; + if (sz_pvt) { + mci->pvt_info = kzalloc(sz_pvt, GFP_KERNEL); + if (!mci->pvt_info) + goto error; + + mci->pvt_managed_by_edac_core = true; + } mci->dev.release = mci_release; device_initialize(&mci->dev); diff --git a/include/linux/edac.h b/include/linux/edac.h index fa4bda2a70f6..6f9f4893ba77 100644 --- a/include/linux/edac.h +++ b/include/linux/edac.h @@ -567,6 +567,11 @@ struct mem_ctl_info { const char *ctl_name; const char *dev_name; void *pvt_info; + /* + * Indicate whether the resource pointed by pvt_info is managed by + * the EDAC core. + */ + bool pvt_managed_by_edac_core; unsigned long start_time; /* mci load start time (in jiffies) */ /* -- 2.17.1
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