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| author | Casey Schaufler <casey@schaufler-ca.com> | 2022-01-27 04:51:00 +0000 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2022-01-27 20:43:02 -0500 |
| commit | ecff30575b5ad0eda149aadad247b7f75411fd47 (patch) | |
| tree | 5d8e8802ce75d4c3e43d7dd1a4c5d0c300e401a5 /security | |
| parent | cdeea45422f579b9302e377d1ede29133d3fde8e (diff) | |
| download | linux-ecff30575b5ad0eda149aadad247b7f75411fd47.tar.gz linux-ecff30575b5ad0eda149aadad247b7f75411fd47.tar.bz2 linux-ecff30575b5ad0eda149aadad247b7f75411fd47.zip | |
LSM: general protection fault in legacy_parse_param
The usual LSM hook "bail on fail" scheme doesn't work for cases where
a security module may return an error code indicating that it does not
recognize an input. In this particular case Smack sees a mount option
that it recognizes, and returns 0. A call to a BPF hook follows, which
returns -ENOPARAM, which confuses the caller because Smack has processed
its data.
The SELinux hook incorrectly returns 1 on success. There was a time
when this was correct, however the current expectation is that it
return 0 on success. This is repaired.
Reported-by: syzbot+d1e3b1d92d25abf97943@syzkaller.appspotmail.com
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/security.c | 17 | ||||
| -rw-r--r-- | security/selinux/hooks.c | 5 |
2 files changed, 17 insertions, 5 deletions
diff --git a/security/security.c b/security/security.c index 3d4eb474f35b..e649c8691be2 100644 --- a/security/security.c +++ b/security/security.c @@ -884,9 +884,22 @@ int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc) return call_int_hook(fs_context_dup, 0, fc, src_fc); } -int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param) +int security_fs_context_parse_param(struct fs_context *fc, + struct fs_parameter *param) { - return call_int_hook(fs_context_parse_param, -ENOPARAM, fc, param); + struct security_hook_list *hp; + int trc; + int rc = -ENOPARAM; + + hlist_for_each_entry(hp, &security_hook_heads.fs_context_parse_param, + list) { + trc = hp->hook.fs_context_parse_param(fc, param); + if (trc == 0) + rc = 0; + else if (trc != -ENOPARAM) + return trc; + } + return rc; } int security_sb_alloc(struct super_block *sb) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 221e642025f5..9e3658e9e7ca 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2859,10 +2859,9 @@ static int selinux_fs_context_parse_param(struct fs_context *fc, return opt; rc = selinux_add_opt(opt, param->string, &fc->security); - if (!rc) { + if (!rc) param->string = NULL; - rc = 1; - } + return rc; } |