mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-29 13:53:33 +00:00
Code Issues Releases Wiki Activity

RDMA/ucma: Protect mc during concurrent multicast leaves

Browse source 
commit 36e8169ec9 upstream.

Partially revert the commit mentioned in the Fixes line to make sure that
allocation and erasing multicast struct are locked.

  BUG: KASAN: use-after-free in ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]
  BUG: KASAN: use-after-free in ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579
  Read of size 8 at addr ffff88801bb74b00 by task syz-executor.1/25529
  CPU: 0 PID: 25529 Comm: syz-executor.1 Not tainted 5.16.0-rc7-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:88 [inline]
   dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
   print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247
   __kasan_report mm/kasan/report.c:433 [inline]
   kasan_report.cold+0x83/0xdf mm/kasan/report.c:450
   ucma_cleanup_multicast drivers/infiniband/core/ucma.c:491 [inline]
   ucma_destroy_private_ctx+0x914/0xb70 drivers/infiniband/core/ucma.c:579
   ucma_destroy_id+0x1e6/0x280 drivers/infiniband/core/ucma.c:614
   ucma_write+0x25c/0x350 drivers/infiniband/core/ucma.c:1732
   vfs_write+0x28e/0xae0 fs/read_write.c:588
   ksys_write+0x1ee/0x250 fs/read_write.c:643
   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
   do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Currently the xarray search can touch a concurrently freeing mc as the
xa_for_each() is not surrounded by any lock. Rather than hold the lock for
a full scan hold it only for the effected items, which is usually an empty
list.

Fixes: 95fe51096b ("RDMA/ucma: Remove mc_list and rely on xarray")
Link: https://lore.kernel.org/r/1cda5fabb1081e8d16e39a48d3a4f8160cea88b8.1642491047.git.leonro@nvidia.com
Reported-by: syzbot+e3f96c43d19782dd14a7@syzkaller.appspotmail.com
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Leon Romanovsky 2022-01-18 09:35:01 +02:00 committed by Greg Kroah-Hartman
parent 7715682f35
commit 2923948ffe
1 changed files with 23 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
drivers/infiniband/core/ucma.c
View file

@ -95,6 +95,7 @@ struct ucma_context {
u64 uid;
struct list_head list;
struct list_head mc_list;
struct work_struct close_work;
};
@ -105,6 +106,7 @@ struct ucma_multicast {
u64 uid;
u8 join_state;
struct list_head list;
struct sockaddr_storage addr;
};
@ -198,6 +200,7 @@ static struct ucma_context *ucma_alloc_ctx(struct ucma_file *file)
INIT_WORK(&ctx->close_work, ucma_close_id);
init_completion(&ctx->comp);
INIT_LIST_HEAD(&ctx->mc_list);
/* So list_del() will work if we don't do ucma_finish_ctx() */
INIT_LIST_HEAD(&ctx->list);
ctx->file = file;
@ -484,19 +487,19 @@ static ssize_t ucma_create_id(struct ucma_file *file, const char __user *inbuf,
static void ucma_cleanup_multicast(struct ucma_context *ctx)
{
struct ucma_multicast *mc;
unsigned long index;
struct ucma_multicast *mc, *tmp;
xa_for_each(&multicast_table, index, mc) {
if (mc->ctx != ctx)
continue;
xa_lock(&multicast_table);
list_for_each_entry_safe(mc, tmp, &ctx->mc_list, list) {
list_del(&mc->list);
/*
* At this point mc->ctx->ref is 0 so the mc cannot leave the
* lock on the reader and this is enough serialization
*/
xa_erase(&multicast_table, index);
__xa_erase(&multicast_table, mc->id);
kfree(mc);
}
xa_unlock(&multicast_table);
}
static void ucma_cleanup_mc_events(struct ucma_multicast *mc)
@ -1469,12 +1472,16 @@ static ssize_t ucma_process_join(struct ucma_file *file,
mc->uid = cmd->uid;
memcpy(&mc->addr, addr, cmd->addr_size);
if (xa_alloc(&multicast_table, &mc->id, NULL, xa_limit_32b,
xa_lock(&multicast_table);
if (__xa_alloc(&multicast_table, &mc->id, NULL, xa_limit_32b,
GFP_KERNEL)) {
ret = -ENOMEM;
goto err_free_mc;
}
list_add_tail(&mc->list, &ctx->mc_list);
xa_unlock(&multicast_table);
mutex_lock(&ctx->mutex);
ret = rdma_join_multicast(ctx->cm_id, (struct sockaddr *)&mc->addr,
join_state, mc);
@ -1500,8 +1507,11 @@ static ssize_t ucma_process_join(struct ucma_file *file,
mutex_unlock(&ctx->mutex);
ucma_cleanup_mc_events(mc);
err_xa_erase:
xa_erase(&multicast_table, mc->id);
xa_lock(&multicast_table);
list_del(&mc->list);
__xa_erase(&multicast_table, mc->id);
err_free_mc:
xa_unlock(&multicast_table);
kfree(mc);
err_put_ctx:
ucma_put_ctx(ctx);
@ -1569,15 +1579,17 @@ static ssize_t ucma_leave_multicast(struct ucma_file *file,
mc = ERR_PTR(-EINVAL);
else if (!refcount_inc_not_zero(&mc->ctx->ref))
mc = ERR_PTR(-ENXIO);
else
__xa_erase(&multicast_table, mc->id);
xa_unlock(&multicast_table);
if (IS_ERR(mc)) {
xa_unlock(&multicast_table);
ret = PTR_ERR(mc);
goto out;
}
list_del(&mc->list);
__xa_erase(&multicast_table, mc->id);
xa_unlock(&multicast_table);
mutex_lock(&mc->ctx->mutex);
rdma_leave_multicast(mc->ctx->cm_id, (struct sockaddr *) &mc->addr);
mutex_unlock(&mc->ctx->mutex);