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 (/home/user/Kernel/v5.19
/x86_64/src/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 (/home/user/Kernel/v5.19/x86_64/src/drivers/net
/ethernet/netronome/nfp/nfpcore/nfp6000_pcie.c:760)
area_cache_get.constprop.8 (/home/user/Kernel/v5.19/x86_64/src/drivers
/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:884)
Allocated by task 1:
nfp_cpp_area_alloc_with_name (/home/user/Kernel/v5.19/x86_64/src/drivers
/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:303)
nfp_cpp_area_cache_add (/home/user/Kernel/v5.19/x86_64/src/drivers/net
/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:802)
nfp6000_init (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
/netronome/nfp/nfpcore/nfp6000_pcie.c:1230)
nfp_cpp_from_operations (/home/user/Kernel/v5.19/x86_64/src/drivers/net
/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:1215)
nfp_pci_probe (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
/netronome/nfp/nfp_main.c:744)
Freed by task 1:
kfree (/home/user/Kernel/v5.19/x86_64/src/mm/slub.c:4562)
area_cache_get.constprop.8 (/home/user/Kernel/v5.19/x86_64/src/drivers
/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:873)
nfp_cpp_read (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
/netronome/nfp/nfpcore/nfp_cppcore.c:924 /home/user/Kernel/v5.19/x86_64
/src/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:973)
nfp_cpp_readl (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
/netronome/nfp/nfpcore/nfp_cpplib.c:48)
Signed-off-by: Jialiang Wang <[email protected]>
---
drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
index 34c0d2ddf9ef..a83b8ee49062 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
@@ -873,10 +873,6 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
cache->addr = 0;
}
- /* 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 */
if (cpp->op->area_init) {
err = cpp->op->area_init(cache->area,
@@ -894,6 +890,10 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
return NULL;
}
+ /* Adjust the start address to be cache size aligned */
+ cache->id = id;
+ cache->addr = addr & ~(u64)(cache->size - 1);
+
exit:
/* Adjust offset */
*offset = addr - cache->addr;
--
2.17.1
On Wed, 10 Aug 2022 12:04:45 +0800 Jialiang Wang wrote:
> diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
> b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
> index 34c0d2ddf9ef..a83b8ee49062 100644
> --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
> +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c
> @@ -873,10 +873,6 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
> cache->addr = 0;
> }
>
> - /* 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 */
> if (cpp->op->area_init) {
> err = cpp->op->area_init(cache->area,
> @@ -894,6 +890,10 @@ area_cache_get(struct nfp_cpp *cpp, u32 id,
> return NULL;
> }
>
> + /* Adjust the start address to be cache size aligned */
> + cache->id = id;
> + cache->addr = addr & ~(u64)(cache->size - 1);
`cache->addr` is used in `area_init`, so it should be set in advance.
> +
> exit:
> /* Adjust offset */
> *offset = addr - cache->addr;
> --
> 2.17.1