Messages in this thread Patch in this message | | | From | Qiuxu Zhuo <> | Subject | [PATCH 2/3] EDAC/device: Fix potential slab-use-after-free | Date | Sun, 8 Oct 2023 16:02:30 +0800 |
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From: Lili Li <lili.li@intel.com>
If the EDAC driver invokes edac_device_alloc_ctl_info() with pvt_sz=0, the EDAC driver itself may manage 'pvt_info' and the EDAC core shouldn't kfree it when unloading the EDAC driver. Otherwise it may lead to a slab-use-after-free bug. Fix the potential bug 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.
Fixes: 9fb9ce392aae ("EDAC/device: Get rid of the silly one-shot memory allocation in edac_device_alloc_ctl_info()") Suggested-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> Signed-off-by: Lili Li <lili.li@intel.com> --- drivers/edac/edac_device.c | 1 + drivers/edac/edac_device.h | 8 +++++++- 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c index 0689e1510721..b990431df2eb 100644 --- a/drivers/edac/edac_device.c +++ b/drivers/edac/edac_device.c @@ -100,6 +100,7 @@ edac_device_alloc_ctl_info(unsigned pvt_sz, char *dev_name, unsigned nr_instance goto free; dev_ctl->pvt_info = pvt; + dev_ctl->pvt_managed_by_edac_core = true; } dev_ctl->dev_idx = device_index; diff --git a/drivers/edac/edac_device.h b/drivers/edac/edac_device.h index 3f44e6b9d387..cc6a364a4b83 100644 --- a/drivers/edac/edac_device.h +++ b/drivers/edac/edac_device.h @@ -197,6 +197,11 @@ struct edac_device_ctl_info { const char *dev_name; /* pci/platform/etc... name */ void *pvt_info; /* pointer to 'private driver' 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; /* edac_device load start time (jiffies) */ @@ -355,7 +360,8 @@ extern const char *edac_layer_name[]; static inline void __edac_device_free_ctl_info(struct edac_device_ctl_info *ci) { if (ci) { - kfree(ci->pvt_info); + if (ci->pvt_managed_by_edac_core) + kfree(ci->pvt_info); kfree(ci->attribs); kfree(ci->blocks); kfree(ci->instances); -- 2.17.1
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