This is a note to let you know that I've just added the patch titled
RDMA/core: Fix overwriting of uobj in case of error
to the 5.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rdma-core-fix-overwriting-of-uobj-in-case-of-error.patch
and it can be found in the queue-5.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8662b92911c15a54710966d731853f7b4a8b91c7
Author: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Date: Tue Apr 21 11:29:29 2020 +0300
RDMA/core: Fix overwriting of uobj in case of error
commit 83a2670212215a569ed133efc10c92055c96cc8c upstream.
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@xxxxxxxxxx
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
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;
