From: Leon Romanovsky leonro@mellanox.com
[ Upstream commit 83a2670212215a569ed133efc10c92055c96cc8c ]
In case of failure to get file, the uobj is overwritten and causes to supply bad pointer as an input to uverbs_uobject_put().
BUG: KASAN: null-ptr-deref in atomic_fetch_sub include/asm-generic/atomic-instrumented.h:199 [inline] BUG: KASAN: null-ptr-deref in refcount_sub_and_test include/linux/refcount.h:253 [inline] BUG: KASAN: null-ptr-deref in refcount_dec_and_test include/linux/refcount.h:281 [inline] BUG: KASAN: null-ptr-deref in kref_put include/linux/kref.h:64 [inline] BUG: KASAN: null-ptr-deref in uverbs_uobject_put+0x22/0x90 drivers/infiniband/core/rdma_core.c:57 Write of size 4 at addr 0000000000000030 by task syz-executor.4/1691
CPU: 1 PID: 1691 Comm: syz-executor.4 Not tainted 5.6.0 #17 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x94/0xce lib/dump_stack.c:118 __kasan_report+0x10c/0x190 mm/kasan/report.c:515 kasan_report+0x32/0x50 mm/kasan/common.c:625 check_memory_region_inline mm/kasan/generic.c:187 [inline] check_memory_region+0x16d/0x1c0 mm/kasan/generic.c:193 atomic_fetch_sub include/asm-generic/atomic-instrumented.h:199 [inline] refcount_sub_and_test include/linux/refcount.h:253 [inline] refcount_dec_and_test include/linux/refcount.h:281 [inline] kref_put include/linux/kref.h:64 [inline] uverbs_uobject_put+0x22/0x90 drivers/infiniband/core/rdma_core.c:57 alloc_begin_fd_uobject+0x1d0/0x250 drivers/infiniband/core/rdma_core.c:486 rdma_alloc_begin_uobject+0xa8/0xf0 drivers/infiniband/core/rdma_core.c:509 __uobj_alloc include/rdma/uverbs_std_types.h:117 [inline] ib_uverbs_create_comp_channel+0x16d/0x230 drivers/infiniband/core/uverbs_cmd.c:982 ib_uverbs_write+0xaa5/0xdf0 drivers/infiniband/core/uverbs_main.c:665 __vfs_write+0x7c/0x100 fs/read_write.c:494 vfs_write+0x168/0x4a0 fs/read_write.c:558 ksys_write+0xc8/0x200 fs/read_write.c:611 do_syscall_64+0x9c/0x390 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x466479 Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007efe9f6a7c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000073bf00 RCX: 0000000000466479 RDX: 0000000000000018 RSI: 0000000020000040 RDI: 0000000000000003 RBP: 00007efe9f6a86bc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005 R13: 0000000000000bf2 R14: 00000000004cb80a R15: 00000000006fefc0
Fixes: 849e149063bd ("RDMA/core: Do not allow alloc_commit to fail") Link: https://lore.kernel.org/r/20200421082929.311931-3-leon@kernel.org Signed-off-by: Leon Romanovsky leonro@mellanox.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/core/rdma_core.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c index 8f480de5596a2..2947f4f83561d 100644 --- a/drivers/infiniband/core/rdma_core.c +++ b/drivers/infiniband/core/rdma_core.c @@ -474,16 +474,15 @@ alloc_begin_fd_uobject(const struct uverbs_api_object *obj, filp = anon_inode_getfile(fd_type->name, fd_type->fops, NULL, fd_type->flags); if (IS_ERR(filp)) { + uverbs_uobject_put(uobj); uobj = ERR_CAST(filp); - goto err_uobj; + goto err_fd; } uobj->object = filp;
uobj->id = new_fd; return uobj;
-err_uobj: - uverbs_uobject_put(uobj); err_fd: put_unused_fd(new_fd); return uobj;