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linux/net/unix
Adrian Huang bc23d4e308 af_unix: Fix memory leak in unix_dgram_sendmsg()
After running the 'sendmsg02' program of Linux Test Project (LTP),
kmemleak reports the following memory leak:

  # cat /sys/kernel/debug/kmemleak
  unreferenced object 0xffff888243866800 (size 2048):
    comm "sendmsg02", pid 67, jiffies 4294903166
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 5e 00 00 00 00 00 00 00  ........^.......
      01 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............
    backtrace (crc 7e96a3f2):
      kmemleak_alloc+0x56/0x90
      kmem_cache_alloc_noprof+0x209/0x450
      sk_prot_alloc.constprop.0+0x60/0x160
      sk_alloc+0x32/0xc0
      unix_create1+0x67/0x2b0
      unix_create+0x47/0xa0
      __sock_create+0x12e/0x200
      __sys_socket+0x6d/0x100
      __x64_sys_socket+0x1b/0x30
      x64_sys_call+0x7e1/0x2140
      do_syscall_64+0x54/0x110
      entry_SYSCALL_64_after_hwframe+0x76/0x7e

Commit 689c398885 ("af_unix: Defer sock_put() to clean up path in
unix_dgram_sendmsg().") defers sock_put() in the error handling path.
However, it fails to account for the condition 'msg->msg_namelen != 0',
resulting in a memory leak when the code jumps to the 'lookup' label.

Fix issue by calling sock_put() if 'msg->msg_namelen != 0' is met.

Fixes: 689c398885 ("af_unix: Defer sock_put() to clean up path in unix_dgram_sendmsg().")
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Acked-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250225021457.1824-1-ahuang12@lenovo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-26 19:01:36 -08:00
..
af_unix.c af_unix: Fix memory leak in unix_dgram_sendmsg() 2025-02-26 19:01:36 -08:00
diag.c af_unix: Remove U_LOCK_DIAG. 2024-06-25 11:10:18 +02:00
garbage.c af_unix: Set drop reason in __unix_gc(). 2025-01-20 11:27:41 -08:00
Kconfig af_unix: Add a prompt to CONFIG_AF_UNIX_OOB 2024-12-19 19:16:15 -08:00
Makefile af_unix: Remove CONFIG_UNIX_SCM. 2024-01-31 16:41:16 -08:00
sysctl_net_unix.c net: Remove the now superfluous sentinel elements from ctl_table array 2024-05-03 13:29:41 +01:00
unix_bpf.c af_unix: Disable MSG_OOB handling for sockets in sockmap/sockhash 2024-07-17 22:49:00 +02:00