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Hallyn" , Khadija Kamran , Casey Schaufler , Ondrej Mosnacek , Kees Cook , John Johansen , Lukas Bulwahn , Roberto Sassu , Shung-Hsi Yu Subject: [PATCH bpf-next v3 02/11] bpf, lsm: Add helper to read lsm hook return value range Date: Thu, 11 Apr 2024 20:27:43 +0800 Message-Id: <20240411122752.2873562-3-xukuohai@huaweicloud.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240411122752.2873562-1-xukuohai@huaweicloud.com> References: <20240411122752.2873562-1-xukuohai@huaweicloud.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgA3h2mJ1hdmZ5R_Jw--.23051S4 X-Coremail-Antispam: 1UD129KBjvJXoWxCF45uFy8AF1xGryxZFWxCrg_yoW5Kr45pF sxAF45ArZ8Aa1agF13AF4rA3W3XF1vqw4UJFy7Gry2ya1Svw1kXa1DGrn8tr93WrWqkw13 CF4jg3yfC347ZaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBYb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij64 vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8G jcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0xvE2I x0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY6xAI w20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x 0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU1sa9DUUUUU== X-CM-SenderInfo: 50xn30hkdlqx5xdzvxpfor3voofrz/ X-Patchwork-Delegate: bpf@iogearbox.net From: Xu Kuohai Add helper to read lsm hook return value range. The following patch will use this information to verify lsm hook return values in bpf verifier. Signed-off-by: Xu Kuohai --- include/linux/bpf_lsm.h | 8 ++++++ kernel/bpf/bpf_lsm.c | 54 ++++++++++++++++++++++++++++++++++++++++- 2 files changed, 61 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h index 1de7ece5d36d..e51c042abf43 100644 --- a/include/linux/bpf_lsm.h +++ b/include/linux/bpf_lsm.h @@ -9,6 +9,7 @@ #include #include +#include #include #ifdef CONFIG_BPF_LSM @@ -45,6 +46,8 @@ void bpf_inode_storage_free(struct inode *inode); void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, bpf_func_t *bpf_func); +int bpf_lsm_get_retval_range(const struct bpf_prog *prog, + struct bpf_retval_range *range); #else /* !CONFIG_BPF_LSM */ static inline bool bpf_lsm_is_sleepable_hook(u32 btf_id) @@ -78,6 +81,11 @@ static inline void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, { } +static inline int bpf_lsm_get_retval_range(const struct bpf_prog *prog, + struct bpf_retval_range *range) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_BPF_LSM */ #endif /* _LINUX_BPF_LSM_H */ diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index ee9d1a795334..4e1a4a333000 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include #include @@ -40,6 +39,29 @@ noinline RET bpf_lsm_##NAME(__VA_ARGS__) \ #undef LSM_RET_INT #undef LSM_RET_VOID +struct lsm_retval_desc { + unsigned long func_addr; + int minval; + int maxval; +}; + +#define LSM_RET_INT(defval, min, max) min, max + +#define LSM_HOOK_RETVAL_int(NAME, ...) \ +{ (unsigned long)&bpf_lsm_##NAME, __VA_ARGS__ }, + +#define LSM_HOOK_RETVAL_void(NAME, ...) + +#define LSM_HOOK(RET, RET_DESCRIPTION, NAME, ...) \ +LSM_HOOK_RETVAL_##RET(NAME, RET_DESCRIPTION) + +static struct lsm_retval_desc lsm_retvalues[] = { +#include +}; +#undef LSM_HOOK +#undef LSM_RET_INT +#undef LSM_RET_VOID + #define LSM_HOOK(RET, DEFAULT, NAME, ...) BTF_ID(func, bpf_lsm_##NAME) BTF_SET_START(bpf_lsm_hooks) #include @@ -399,3 +421,33 @@ const struct bpf_verifier_ops lsm_verifier_ops = { .get_func_proto = bpf_lsm_func_proto, .is_valid_access = btf_ctx_access, }; + +static struct lsm_retval_desc *find_retval_desc(const char *func_name) +{ + unsigned long addr; + struct lsm_retval_desc *desc; + + addr = kallsyms_lookup_name(func_name); + for (unsigned int i = 0U; i < ARRAY_SIZE(lsm_retvalues); i++) { + desc = &lsm_retvalues[i]; + if (addr == desc->func_addr) + return desc; + } + + return NULL; +} + +int bpf_lsm_get_retval_range(const struct bpf_prog *prog, + struct bpf_retval_range *retval_range) +{ + struct lsm_retval_desc *desc; + + desc = find_retval_desc(prog->aux->attach_func_name); + if (desc == NULL) + return -ENODEV; + + retval_range->minval = desc->minval; + retval_range->maxval = desc->maxval; + + return 0; +}