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LSM: general protection fault in legacy_parse_param
[ Upstream commit ecff30575b
]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
28dfe0fc11
commit
cadae7c5e4
2 changed files with 17 additions and 5 deletions
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@ -884,9 +884,22 @@ int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
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return call_int_hook(fs_context_dup, 0, fc, src_fc);
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}
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int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param)
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int security_fs_context_parse_param(struct fs_context *fc,
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struct fs_parameter *param)
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{
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return call_int_hook(fs_context_parse_param, -ENOPARAM, fc, param);
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struct security_hook_list *hp;
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int trc;
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int rc = -ENOPARAM;
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hlist_for_each_entry(hp, &security_hook_heads.fs_context_parse_param,
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list) {
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trc = hp->hook.fs_context_parse_param(fc, param);
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if (trc == 0)
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rc = 0;
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else if (trc != -ENOPARAM)
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return trc;
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}
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return rc;
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}
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int security_sb_alloc(struct super_block *sb)
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@ -2867,10 +2867,9 @@ static int selinux_fs_context_parse_param(struct fs_context *fc,
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return opt;
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rc = selinux_add_opt(opt, param->string, &fc->security);
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if (!rc) {
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if (!rc)
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param->string = NULL;
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rc = 1;
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}
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return rc;
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}
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