From: Jialiang Wang <wangjialiang0806@xxxxxxx> commit 02e1a114fdb71e59ee6770294166c30d437bf86a upstream. area_cache_get() is used to distribute cache->area and set cache->id, and if cache->id is not 0 and cache->area->kref refcount is 0, it will release the cache->area by nfp_cpp_area_release(). area_cache_get() set cache->id before cpp->op->area_init() and nfp_cpp_area_acquire(). But if area_init() or nfp_cpp_area_acquire() fails, the cache->id is is already set but the refcount is not increased as expected. At this time, calling the nfp_cpp_area_release() will cause use-after-free. To avoid the use-after-free, set cache->id after area_init() and nfp_cpp_area_acquire() complete successfully. Note: This vulnerability is triggerable by providing emulated device equipped with specified configuration. BUG: KASAN: use-after-free in nfp6000_area_init (drivers/net/ethernet/netronome/nfp/nfpcore/nfp6000_pcie.c:760) Write of size 4 at addr ffff888005b7f4a0 by task swapper/0/1 Call Trace: <TASK> nfp6000_area_init (drivers/net/ethernet/netronome/nfp/nfpcore/nfp6000_pcie.c:760) area_cache_get.constprop.8 (drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:884) Allocated by task 1: nfp_cpp_area_alloc_with_name (drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:303) nfp_cpp_area_cache_add (drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:802) nfp6000_init (drivers/net/ethernet/netronome/nfp/nfpcore/nfp6000_pcie.c:1230) nfp_cpp_from_operations (drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:1215) nfp_pci_probe (drivers/net/ethernet/netronome/nfp/nfp_main.c:744) Freed by task 1: kfree (mm/slub.c:4562) area_cache_get.constprop.8 (drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:873) nfp_cpp_read (drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:924 drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:973) nfp_cpp_readl (drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpplib.c:48) Signed-off-by: Jialiang Wang <wangjialiang0806@xxxxxxx> Reviewed-by: Yinjun Zhang <yinjun.zhang@xxxxxxxxxxxx> Acked-by: Simon Horman <simon.horman@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220810073057.4032-1-wangjialiang0806@xxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c @@ -874,7 +874,6 @@ area_cache_get(struct nfp_cpp *cpp, u32 } /* Adjust the start address to be cache size aligned */ - cache->id = id; cache->addr = addr & ~(u64)(cache->size - 1); /* Re-init to the new ID and address */ @@ -894,6 +893,8 @@ area_cache_get(struct nfp_cpp *cpp, u32 return NULL; } + cache->id = id; + exit: /* Adjust offset */ *offset = addr - cache->addr;
