From cad140d00899e7a9cb6fe93b282051df589e671c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= Date: Wed, 15 Jun 2022 17:38:39 +0200 Subject: [PATCH] selinux: free contexts previously transferred in selinux_add_opt() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit `selinux_add_opt()` stopped taking ownership of the passed context since commit 70f4169ab421 ("selinux: parse contexts for mount options early"). unreferenced object 0xffff888114dfd140 (size 64): comm "mount", pid 15182, jiffies 4295687028 (age 796.340s) hex dump (first 32 bytes): 73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f system_u:object_ 72 3a 74 65 73 74 5f 66 69 6c 65 73 79 73 74 65 r:test_filesyste backtrace: [] kmemdup_nul+0x24/0x80 [] selinux_sb_eat_lsm_opts+0x293/0x560 [] security_sb_eat_lsm_opts+0x58/0x80 [] generic_parse_monolithic+0x82/0x180 [] do_new_mount+0x1f5/0x550 [] path_mount+0x2ab/0x1570 [] __x64_sys_mount+0x20e/0x280 [] do_syscall_64+0x34/0x80 [] entry_SYSCALL_64_after_hwframe+0x46/0xb0 unreferenced object 0xffff888108e71640 (size 64): comm "fsmount", pid 7607, jiffies 4295044974 (age 1601.016s) hex dump (first 32 bytes): 73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f system_u:object_ 72 3a 74 65 73 74 5f 66 69 6c 65 73 79 73 74 65 r:test_filesyste backtrace: [] memdup_user+0x21/0x90 [] strndup_user+0x47/0xa0 [] __do_sys_fsconfig+0x485/0x9f0 [] do_syscall_64+0x34/0x80 [] entry_SYSCALL_64_after_hwframe+0x46/0xb0 Cc: stable@vger.kernel.org Fixes: 70f4169ab421 ("selinux: parse contexts for mount options early") Signed-off-by: Christian Göttsche Signed-off-by: Paul Moore --- security/selinux/hooks.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index beceb89f68d9..1bbd53321d13 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2600,8 +2600,9 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts) } } rc = selinux_add_opt(token, arg, mnt_opts); + kfree(arg); + arg = NULL; if (unlikely(rc)) { - kfree(arg); goto free_opt; } } else { @@ -2792,17 +2793,13 @@ static int selinux_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param) { struct fs_parse_result result; - int opt, rc; + int opt; opt = fs_parse(fc, selinux_fs_parameters, param, &result); if (opt < 0) return opt; - rc = selinux_add_opt(opt, param->string, &fc->security); - if (!rc) - param->string = NULL; - - return rc; + return selinux_add_opt(opt, param->string, &fc->security); } /* inode security operations */